[pypy-commit] pypy default: merge numpy-refactor branch. This branch changes more or less everything

fijal noreply at buildbot.pypy.org
Tue Sep 11 16:04:49 CEST 2012


Author: Maciej Fijalkowski <fijall at gmail.com>
Branch: 
Changeset: r57288:67d9a48f4362
Date: 2012-09-11 16:03 +0200
http://bitbucket.org/pypy/pypy/changeset/67d9a48f4362/

Log:	merge numpy-refactor branch. This branch changes more or less
	everything related to arrays in micronumpy. This means killing lazy
	evaluation, but a lot of complexity as well. Right now the numpy is
	just a thin wrapper around the underlaying implementation. For now
	it's just scalar, concrete array or a view, but this can add virtual
	arrays easily in the future.

diff --git a/lib_pypy/numpypy/core/_methods.py b/lib_pypy/numpypy/core/_methods.py
--- a/lib_pypy/numpypy/core/_methods.py
+++ b/lib_pypy/numpypy/core/_methods.py
@@ -1,62 +1,77 @@
 # Array methods which are called by the both the C-code for the method
 # and the Python code for the NumPy-namespace function
 
+#from numpy.core import multiarray as mu
+#from numpy.core import umath as um
 import _numpypy as mu
 um = mu
-#from numpypy.core import umath as um
-from numpypy.core.numeric import asanyarray
+from numpy.core.numeric import asanyarray
 
-def _amax(a, axis=None, out=None, skipna=False, keepdims=False):
+def _amax(a, axis=None, out=None, keepdims=False):
     return um.maximum.reduce(a, axis=axis,
-                            out=out, skipna=skipna, keepdims=keepdims)
+                            out=out, keepdims=keepdims)
 
-def _amin(a, axis=None, out=None, skipna=False, keepdims=False):
+def _amin(a, axis=None, out=None, keepdims=False):
     return um.minimum.reduce(a, axis=axis,
-                            out=out, skipna=skipna, keepdims=keepdims)
+                            out=out, keepdims=keepdims)
 
-def _sum(a, axis=None, dtype=None, out=None, skipna=False, keepdims=False):
+def _sum(a, axis=None, dtype=None, out=None, keepdims=False):
     return um.add.reduce(a, axis=axis, dtype=dtype,
-                            out=out, skipna=skipna, keepdims=keepdims)
+                            out=out, keepdims=keepdims)
 
-def _prod(a, axis=None, dtype=None, out=None, skipna=False, keepdims=False):
+def _prod(a, axis=None, dtype=None, out=None, keepdims=False):
     return um.multiply.reduce(a, axis=axis, dtype=dtype,
-                            out=out, skipna=skipna, keepdims=keepdims)
+                            out=out, keepdims=keepdims)
 
-def _mean(a, axis=None, dtype=None, out=None, skipna=False, keepdims=False):
+def _any(a, axis=None, dtype=None, out=None, keepdims=False):
+    return um.logical_or.reduce(a, axis=axis, dtype=dtype, out=out,
+                                keepdims=keepdims)
+
+def _all(a, axis=None, dtype=None, out=None, keepdims=False):
+    return um.logical_and.reduce(a, axis=axis, dtype=dtype, out=out,
+                                 keepdims=keepdims)
+
+def _count_reduce_items(arr, axis):
+    if axis is None:
+        axis = tuple(xrange(arr.ndim))
+    if not isinstance(axis, tuple):
+        axis = (axis,)
+    items = 1
+    for ax in axis:
+        items *= arr.shape[ax]
+    return items
+
+def _mean(a, axis=None, dtype=None, out=None, keepdims=False):
     arr = asanyarray(a)
 
     # Upgrade bool, unsigned int, and int to float64
     if dtype is None and arr.dtype.kind in ['b','u','i']:
         ret = um.add.reduce(arr, axis=axis, dtype='f8',
-                            out=out, skipna=skipna, keepdims=keepdims)
+                            out=out, keepdims=keepdims)
     else:
         ret = um.add.reduce(arr, axis=axis, dtype=dtype,
-                            out=out, skipna=skipna, keepdims=keepdims)
-    rcount = mu.count_reduce_items(arr, axis=axis,
-                            skipna=skipna, keepdims=keepdims)
+                            out=out, keepdims=keepdims)
+    rcount = _count_reduce_items(arr, axis)
     if isinstance(ret, mu.ndarray):
         ret = um.true_divide(ret, rcount,
-                        casting='unsafe', subok=False)
+                        out=ret, casting='unsafe', subok=False)
     else:
         ret = ret / float(rcount)
     return ret
 
 def _var(a, axis=None, dtype=None, out=None, ddof=0,
-                            skipna=False, keepdims=False):
+                            keepdims=False):
     arr = asanyarray(a)
 
     # First compute the mean, saving 'rcount' for reuse later
     if dtype is None and arr.dtype.kind in ['b','u','i']:
-        arrmean = um.add.reduce(arr, axis=axis, dtype='f8',
-                            skipna=skipna, keepdims=True)
+        arrmean = um.add.reduce(arr, axis=axis, dtype='f8', keepdims=True)
     else:
-        arrmean = um.add.reduce(arr, axis=axis, dtype=dtype,
-                            skipna=skipna, keepdims=True)
-    rcount = mu.count_reduce_items(arr, axis=axis,
-                            skipna=skipna, keepdims=True)
+        arrmean = um.add.reduce(arr, axis=axis, dtype=dtype, keepdims=True)
+    rcount = _count_reduce_items(arr, axis)
     if isinstance(arrmean, mu.ndarray):
         arrmean = um.true_divide(arrmean, rcount,
-                                  casting='unsafe', subok=False)
+                            out=arrmean, casting='unsafe', subok=False)
     else:
         arrmean = arrmean / float(rcount)
 
@@ -65,13 +80,12 @@
 
     # (arr - arrmean) ** 2
     if arr.dtype.kind == 'c':
-        x = um.multiply(x, um.conjugate(x)).real
+        x = um.multiply(x, um.conjugate(x), out=x).real
     else:
-        x = um.multiply(x, x)
+        x = um.multiply(x, x, out=x)
 
     # add.reduce((arr - arrmean) ** 2, axis)
-    ret = um.add.reduce(x, axis=axis, dtype=dtype, out=out,
-                        skipna=skipna, keepdims=keepdims)
+    ret = um.add.reduce(x, axis=axis, dtype=dtype, out=out, keepdims=keepdims)
 
     # add.reduce((arr - arrmean) ** 2, axis) / (n - ddof)
     if not keepdims and isinstance(rcount, mu.ndarray):
@@ -79,19 +93,18 @@
     rcount -= ddof
     if isinstance(ret, mu.ndarray):
         ret = um.true_divide(ret, rcount,
-                        casting='unsafe', subok=False)
+                        out=ret, casting='unsafe', subok=False)
     else:
         ret = ret / float(rcount)
 
     return ret
 
-def _std(a, axis=None, dtype=None, out=None, ddof=0,
-                            skipna=False, keepdims=False):
+def _std(a, axis=None, dtype=None, out=None, ddof=0, keepdims=False):
     ret = _var(a, axis=axis, dtype=dtype, out=out, ddof=ddof,
-                                skipna=skipna, keepdims=keepdims)
+               keepdims=keepdims)
 
     if isinstance(ret, mu.ndarray):
-        ret = um.sqrt(ret)
+        ret = um.sqrt(ret, out=ret)
     else:
         ret = um.sqrt(ret)
 
diff --git a/lib_pypy/numpypy/core/arrayprint.py b/lib_pypy/numpypy/core/arrayprint.py
--- a/lib_pypy/numpypy/core/arrayprint.py
+++ b/lib_pypy/numpypy/core/arrayprint.py
@@ -14,9 +14,9 @@
 
 import sys
 import _numpypy as _nt
-from _numpypy import maximum, minimum, absolute, not_equal, isinf, isnan, isna
+from _numpypy import maximum, minimum, absolute, not_equal, isnan, isinf
 #from _numpypy import format_longfloat, datetime_as_string, datetime_data
-from .fromnumeric import ravel
+from fromnumeric import ravel
 
 
 def product(x, y): return x*y
@@ -29,7 +29,6 @@
 _line_width = 75
 _nan_str = 'nan'
 _inf_str = 'inf'
-_na_str = 'NA'
 _formatter = None  # formatting function for array elements
 
 if sys.version_info[0] >= 3:
@@ -37,7 +36,7 @@
 
 def set_printoptions(precision=None, threshold=None, edgeitems=None,
                      linewidth=None, suppress=None,
-                     nanstr=None, infstr=None, nastr=None,
+                     nanstr=None, infstr=None,
                      formatter=None):
     """
     Set printing options.
@@ -65,8 +64,6 @@
         String representation of floating point not-a-number (default nan).
     infstr : str, optional
         String representation of floating point infinity (default inf).
-    nastr : str, optional
-        String representation of NA missing value (default NA).
     formatter : dict of callables, optional
         If not None, the keys should indicate the type(s) that the respective
         formatting function applies to.  Callables should return a string.
@@ -144,7 +141,7 @@
 
     global _summaryThreshold, _summaryEdgeItems, _float_output_precision, \
            _line_width, _float_output_suppress_small, _nan_str, _inf_str, \
-           _na_str, _formatter
+           _formatter
     if linewidth is not None:
         _line_width = linewidth
     if threshold is not None:
@@ -159,8 +156,6 @@
         _nan_str = nanstr
     if infstr is not None:
         _inf_str = infstr
-    if nastr is not None:
-        _na_str = nastr
     _formatter = formatter
 
 def get_printoptions():
@@ -195,7 +190,6 @@
              suppress=_float_output_suppress_small,
              nanstr=_nan_str,
              infstr=_inf_str,
-             nastr=_na_str,
              formatter=_formatter)
     return d
 
@@ -219,19 +213,14 @@
     return b
 
 def _boolFormatter(x):
-    if isna(x):
-        return str(x).replace('NA', _na_str, 1)
-    elif x:
+    if x:
         return ' True'
     else:
         return 'False'
 
 
 def repr_format(x):
-    if isna(x):
-        return str(x).replace('NA', _na_str, 1)
-    else:
-        return repr(x)
+    return repr(x)
 
 def _array2string(a, max_line_width, precision, suppress_small, separator=' ',
                   prefix="", formatter=None):
@@ -262,8 +251,8 @@
                   #'complexfloat' : ComplexFormat(data, precision,
                   #                               suppress_small),
                   #'longcomplexfloat' : LongComplexFormat(precision),
-                  #'datetime' : DatetimeFormat(data),
-                  #'timedelta' : TimedeltaFormat(data),
+                  'datetime' : DatetimeFormat(data),
+                  'timedelta' : TimedeltaFormat(data),
                   'numpystr' : repr_format,
                   'str' : str}
 
@@ -309,11 +298,11 @@
             #    format_function = formatdict['longfloat']
             #else:
             format_function = formatdict['float']
-        elif issubclass(dtypeobj, _nt.complexfloating):
-            if issubclass(dtypeobj, _nt.clongfloat):
-                format_function = formatdict['longcomplexfloat']
-            else:
-                format_function = formatdict['complexfloat']
+        #elif issubclass(dtypeobj, _nt.complexfloating):
+        #    if issubclass(dtypeobj, _nt.clongfloat):
+        #        format_function = formatdict['longcomplexfloat']
+        #    else:
+        #        format_function = formatdict['complexfloat']
         elif issubclass(dtypeobj, (_nt.unicode_, _nt.string_)):
             format_function = formatdict['numpystr']
         elif issubclass(dtypeobj, _nt.datetime64):
@@ -437,20 +426,17 @@
 
     if a.shape == ():
         x = a.item()
-        if isna(x):
-            lst = str(x).replace('NA', _na_str, 1)
-        else:
-            try:
-                lst = a._format(x)
-                msg = "The `_format` attribute is deprecated in Numpy " \
-                      "2.0 and will be removed in 2.1. Use the " \
-                      "`formatter` kw instead."
-                import warnings
-                warnings.warn(msg, DeprecationWarning)
-            except AttributeError:
-                if isinstance(x, tuple):
-                    x = _convert_arrays(x)
-                lst = style(x)
+        try:
+            lst = a._format(x)
+            msg = "The `_format` attribute is deprecated in Numpy " \
+                  "2.0 and will be removed in 2.1. Use the " \
+                  "`formatter` kw instead."
+            import warnings
+            warnings.warn(msg, DeprecationWarning)
+        except AttributeError:
+            if isinstance(x, tuple):
+                x = _convert_arrays(x)
+            lst = style(x)
     elif reduce(product, a.shape) == 0:
         # treat as a null array if any of shape elements == 0
         lst = "[]"
@@ -542,38 +528,33 @@
         self.exp_format = False
         self.large_exponent = False
         self.max_str_len = 0
-        #try:
-        self.fillFormat(data)
-        #except (TypeError, NotImplementedError):
+        try:
+            self.fillFormat(data)
+        except (TypeError, NotImplementedError):
             # if reduce(data) fails, this instance will not be called, just
             # instantiated in formatdict.
-            #pass
+            pass
 
     def fillFormat(self, data):
         import numeric as _nc
-        # XXX pypy unimplemented
-        #errstate = _nc.seterr(all='ignore')
+        errstate = _nc.seterr(all='ignore')
         try:
-            special = isnan(data) | isinf(data) | isna(data)
-            special[isna(data)] = False
+            special = isnan(data) | isinf(data)
             valid = not_equal(data, 0) & ~special
-            valid[isna(data)] = False
             non_zero = absolute(data.compress(valid))
             if len(non_zero) == 0:
                 max_val = 0.
                 min_val = 0.
             else:
-                max_val = maximum.reduce(non_zero, skipna=True)
-                min_val = minimum.reduce(non_zero, skipna=True)
+                max_val = maximum.reduce(non_zero)
+                min_val = minimum.reduce(non_zero)
                 if max_val >= 1.e8:
                     self.exp_format = True
                 if not self.suppress_small and (min_val < 0.0001
                                            or max_val/min_val > 1000.):
                     self.exp_format = True
         finally:
-            pass
-            # XXX pypy unimplemented
-            #_nc.seterr(**errstate)
+            _nc.seterr(**errstate)
 
         if self.exp_format:
             self.large_exponent = 0 < min_val < 1e-99 or max_val >= 1e100
@@ -594,11 +575,10 @@
                 precision = 0
             precision = min(self.precision, precision)
             self.max_str_len = len(str(int(max_val))) + precision + 2
-            if special.any():
+            if _nc.any(special):
                 self.max_str_len = max(self.max_str_len,
                                        len(_nan_str),
-                                       len(_inf_str)+1,
-                                       len(_na_str))
+                                       len(_inf_str)+1)
             if self.sign:
                 format = '%#+'
             else:
@@ -610,11 +590,9 @@
 
     def __call__(self, x, strip_zeros=True):
         import numeric as _nc
-        #err = _nc.seterr(invalid='ignore')
+        err = _nc.seterr(invalid='ignore')
         try:
-            if isna(x):
-                return self.special_fmt % (str(x).replace('NA', _na_str, 1),)
-            elif isnan(x):
+            if isnan(x):
                 if self.sign:
                     return self.special_fmt % ('+' + _nan_str,)
                 else:
@@ -628,8 +606,7 @@
                 else:
                     return self.special_fmt % ('-' + _inf_str,)
         finally:
-            pass
-            #_nc.seterr(**err)
+            _nc.seterr(**err)
 
         s = self.format % x
         if self.large_exponent:
@@ -658,10 +635,10 @@
 class IntegerFormat(object):
     def __init__(self, data):
         try:
-            max_str_len = max(len(str(maximum.reduce(data, skipna=True))),
-                              len(str(minimum.reduce(data, skipna=True))))
+            max_str_len = max(len(str(maximum.reduce(data))),
+                              len(str(minimum.reduce(data))))
             self.format = '%' + str(max_str_len) + 'd'
-        except TypeError, NotImplementedError:
+        except (TypeError, NotImplementedError):
             # if reduce(data) fails, this instance will not be called, just
             # instantiated in formatdict.
             pass
@@ -670,9 +647,7 @@
             pass
 
     def __call__(self, x):
-        if isna(x):
-            return str(x).replace('NA', _na_str, 1)
-        elif _MININT < x < _MAXINT:
+        if _MININT < x < _MAXINT:
             return self.format % x
         else:
             return "%s" % x
@@ -685,9 +660,7 @@
         self.sign = sign
 
     def __call__(self, x):
-        if isna(x):
-            return str(x).replace('NA', _na_str, 1)
-        elif isnan(x):
+        if isnan(x):
             if self.sign:
                 return '+' + _nan_str
             else:
@@ -715,12 +688,9 @@
         self.imag_format = LongFloatFormat(precision, sign=True)
 
     def __call__(self, x):
-        if isna(x):
-            return str(x).replace('NA', _na_str, 1)
-        else:
-            r = self.real_format(x.real)
-            i = self.imag_format(x.imag)
-            return r + i + 'j'
+        r = self.real_format(x.real)
+        i = self.imag_format(x.imag)
+        return r + i + 'j'
 
 
 class ComplexFormat(object):
@@ -730,17 +700,14 @@
                                        sign=True)
 
     def __call__(self, x):
-        if isna(x):
-            return str(x).replace('NA', _na_str, 1)
+        r = self.real_format(x.real, strip_zeros=False)
+        i = self.imag_format(x.imag, strip_zeros=False)
+        if not self.imag_format.exp_format:
+            z = i.rstrip('0')
+            i = z + 'j' + ' '*(len(i)-len(z))
         else:
-            r = self.real_format(x.real, strip_zeros=False)
-            i = self.imag_format(x.imag, strip_zeros=False)
-            if not self.imag_format.exp_format:
-                z = i.rstrip('0')
-                i = z + 'j' + ' '*(len(i)-len(z))
-            else:
-                i = i + 'j'
-            return r + i
+            i = i + 'j'
+        return r + i
 
 class DatetimeFormat(object):
     def __init__(self, x, unit=None,
@@ -765,13 +732,10 @@
         self.casting = casting
 
     def __call__(self, x):
-        if isna(x):
-            return str(x).replace('NA', _na_str, 1)
-        else:
-            return "'%s'" % datetime_as_string(x,
-                                        unit=self.unit,
-                                        timezone=self.timezone,
-                                        casting=self.casting)
+        return "'%s'" % datetime_as_string(x,
+                                    unit=self.unit,
+                                    timezone=self.timezone,
+                                    casting=self.casting)
 
 class TimedeltaFormat(object):
     def __init__(self, data):
@@ -782,8 +746,5 @@
             self.format = '%' + str(max_str_len) + 'd'
 
     def __call__(self, x):
-        if isna(x):
-            return str(x).replace('NA', _na_str, 1)
-        else:
-            return self.format % x.astype('i8')
+        return self.format % x.astype('i8')
 
diff --git a/lib_pypy/numpypy/core/numeric.py b/lib_pypy/numpypy/core/numeric.py
--- a/lib_pypy/numpypy/core/numeric.py
+++ b/lib_pypy/numpypy/core/numeric.py
@@ -1,6 +1,7 @@
 
 from _numpypy import array, ndarray, int_, float_, bool_ #, complex_# , longlong
 from _numpypy import concatenate
+from .fromnumeric import any
 import math
 import sys
 import _numpypy as multiarray # ARGH
@@ -8,7 +9,11 @@
 
 newaxis = None
 
-def asanyarray(a, dtype=None, order=None, maskna=None, ownmaskna=False):
+# XXX this file to be reviewed
+def seterr(**args):
+    return args
+
+def asanyarray(a, dtype=None, order=None):
     """
     Convert the input to an ndarray, but pass ndarray subclasses through.
 
@@ -23,13 +28,6 @@
     order : {'C', 'F'}, optional
         Whether to use row-major ('C') or column-major ('F') memory
         representation.  Defaults to 'C'.
-   maskna : bool or None, optional
-        If this is set to True, it forces the array to have an NA mask.
-        If this is set to False, it forces the array to not have an NA
-        mask.
-    ownmaskna : bool, optional
-        If this is set to True, forces the array to have a mask which
-        it owns.
 
     Returns
     -------
@@ -65,8 +63,7 @@
     True
 
     """
-    return array(a, dtype, copy=False, order=order, subok=True,
-                                maskna=maskna, ownmaskna=ownmaskna)
+    return array(a, dtype, copy=False, order=order, subok=True)
 
 def base_repr(number, base=2, padding=0):
     """
@@ -347,7 +344,7 @@
         return False
     return bool((a1 == a2).all())
 
-def asarray(a, dtype=None, order=None, maskna=None, ownmaskna=False):
+def asarray(a, dtype=None, order=None):
     """
     Convert the input to an array.
 
@@ -362,13 +359,6 @@
     order : {'C', 'F'}, optional
         Whether to use row-major ('C') or column-major ('F' for FORTRAN)
         memory representation.  Defaults to 'C'.
-   maskna : bool or None, optional
-        If this is set to True, it forces the array to have an NA mask.
-        If this is set to False, it forces the array to not have an NA
-        mask.
-    ownmaskna : bool, optional
-        If this is set to True, forces the array to have a mask which
-        it owns.
 
     Returns
     -------
@@ -422,8 +412,7 @@
     True
 
     """
-    return array(a, dtype, copy=False, order=order,
-                            maskna=maskna, ownmaskna=ownmaskna)
+    return array(a, dtype, copy=False, order=order)
 
 set_string_function(array_str, 0)
 set_string_function(array_repr, 1)
diff --git a/pypy/module/micronumpy/__init__.py b/pypy/module/micronumpy/__init__.py
--- a/pypy/module/micronumpy/__init__.py
+++ b/pypy/module/micronumpy/__init__.py
@@ -25,18 +25,16 @@
         'zeros': 'interp_numarray.zeros',
         'empty': 'interp_numarray.zeros',
         'ones': 'interp_numarray.ones',
-        'dot': 'interp_numarray.dot',
+        'dot': 'interp_arrayops.dot',
         'fromstring': 'interp_support.fromstring',
-        'flatiter': 'interp_numarray.W_FlatIterator',
-        'isna': 'interp_numarray.isna',
-        'concatenate': 'interp_numarray.concatenate',
-        'repeat': 'interp_numarray.repeat',
+        'flatiter': 'interp_flatiter.W_FlatIterator',
+        'concatenate': 'interp_arrayops.concatenate',
+        'repeat': 'interp_arrayops.repeat',
         'where': 'interp_arrayops.where',
+        'count_nonzero': 'interp_arrayops.count_nonzero',
 
         'set_string_function': 'appbridge.set_string_function',
 
-        'count_reduce_items': 'interp_numarray.count_reduce_items',
-
         'True_': 'types.Bool.True',
         'False_': 'types.Bool.False',
 
@@ -166,5 +164,4 @@
         'eye': 'app_numpy.eye',
         'max': 'app_numpy.max',
         'arange': 'app_numpy.arange',
-        'count_nonzero': 'app_numpy.count_nonzero',
     }
diff --git a/pypy/module/micronumpy/app_numpy.py b/pypy/module/micronumpy/app_numpy.py
--- a/pypy/module/micronumpy/app_numpy.py
+++ b/pypy/module/micronumpy/app_numpy.py
@@ -2,11 +2,6 @@
 
 import _numpypy
 
-def count_nonzero(a):
-    if not hasattr(a, 'count_nonzero'):
-        a = _numpypy.array(a)
-    return a.count_nonzero()
-
 def average(a):
     # This implements a weighted average, for now we don't implement the
     # weighting, just the average part!
diff --git a/pypy/module/micronumpy/arrayimpl/__init__.py b/pypy/module/micronumpy/arrayimpl/__init__.py
new file mode 100644
diff --git a/pypy/module/micronumpy/arrayimpl/base.py b/pypy/module/micronumpy/arrayimpl/base.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/micronumpy/arrayimpl/base.py
@@ -0,0 +1,14 @@
+
+class BaseArrayImplementation(object):
+    def is_scalar(self):
+        return False
+
+class BaseArrayIterator(object):
+    def next(self):
+        raise NotImplementedError # purely abstract base class
+
+    def setitem(self, elem):
+        raise NotImplementedError
+
+    def set_scalar_object(self, value):
+        raise NotImplementedError # works only on scalars
diff --git a/pypy/module/micronumpy/arrayimpl/concrete.py b/pypy/module/micronumpy/arrayimpl/concrete.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/micronumpy/arrayimpl/concrete.py
@@ -0,0 +1,430 @@
+
+from pypy.module.micronumpy.arrayimpl import base
+from pypy.module.micronumpy import support, loop
+from pypy.module.micronumpy.base import convert_to_array, W_NDimArray
+from pypy.module.micronumpy.strides import calc_new_strides, shape_agreement,\
+     calculate_broadcast_strides, calculate_dot_strides
+from pypy.module.micronumpy.iter import Chunk, Chunks, NewAxisChunk, RecordChunk
+from pypy.interpreter.error import OperationError, operationerrfmt
+from pypy.rpython.lltypesystem import rffi, lltype
+from pypy.rlib import jit
+from pypy.rlib.rawstorage import free_raw_storage
+
+class ConcreteArrayIterator(base.BaseArrayIterator):
+    def __init__(self, array):
+        self.array = array
+        self.offset = 0
+        self.dtype = array.dtype
+        self.skip = self.dtype.itemtype.get_element_size()
+        self.size = array.size
+
+    def setitem(self, elem):
+        self.array.setitem(self.offset, elem)
+
+    def getitem(self):
+        return self.array.getitem(self.offset)
+
+    def getitem_bool(self):
+        return self.dtype.getitem_bool(self.array, self.offset)
+
+    def next(self):
+        self.offset += self.skip
+
+    def next_skip_x(self, x):
+        self.offset += self.skip * x
+
+    def done(self):
+        return self.offset >= self.size
+
+    def reset(self):
+        self.offset %= self.size
+
+class OneDimViewIterator(ConcreteArrayIterator):
+    def __init__(self, array):
+        self.array = array
+        self.offset = array.start
+        self.skip = array.strides[0]
+        self.dtype = array.dtype
+        self.index = 0
+        self.size = array.shape[0]
+
+    def next(self):
+        self.offset += self.skip
+        self.index += 1
+
+    def next_skip_x(self, x):
+        self.offset += self.skip * x
+        self.index += x
+
+    def done(self):
+        return self.index >= self.size
+
+    def reset(self):
+        self.offset %= self.size
+
+class MultiDimViewIterator(ConcreteArrayIterator):
+    def __init__(self, array, start, strides, backstrides, shape):
+        self.indexes = [0] * len(shape)
+        self.array = array
+        self.shape = shape
+        self.offset = start
+        self.shapelen = len(shape)
+        self._done = False
+        self.strides = strides
+        self.backstrides = backstrides
+        self.size = array.size
+
+    @jit.unroll_safe
+    def next(self):
+        offset = self.offset
+        for i in range(self.shapelen - 1, -1, -1):
+            if self.indexes[i] < self.shape[i] - 1:
+                self.indexes[i] += 1
+                offset += self.strides[i]
+                break
+            else:
+                self.indexes[i] = 0
+                offset -= self.backstrides[i]
+        else:
+            self._done = True
+        self.offset = offset
+
+    @jit.unroll_safe
+    def next_skip_x(self, step):
+        for i in range(len(self.shape) - 1, -1, -1):
+            if self.indexes[i] < self.shape[i] - step:
+                self.indexes[i] += step
+                self.offset += self.strides[i] * step
+                break
+            else:
+                remaining_step = (self.indexes[i] + step) // self.shape[i]
+                this_i_step = step - remaining_step * self.shape[i]
+                self.offset += self.strides[i] * this_i_step
+                self.indexes[i] = self.indexes[i] +  this_i_step
+                step = remaining_step
+        else:
+            self._done = True
+
+    def done(self):
+        return self._done
+
+    def reset(self):
+        self.offset %= self.size
+
+class AxisIterator(base.BaseArrayIterator):
+    def __init__(self, array, shape, dim):
+        self.shape = shape
+        strides = array.strides
+        backstrides = array.backstrides
+        if len(shape) == len(strides):
+            # keepdims = True
+            self.strides = strides[:dim] + [0] + strides[dim + 1:]
+            self.backstrides = backstrides[:dim] + [0] + backstrides[dim + 1:]
+        else:
+            self.strides = strides[:dim] + [0] + strides[dim:]
+            self.backstrides = backstrides[:dim] + [0] + backstrides[dim:]
+        self.first_line = True
+        self.indices = [0] * len(shape)
+        self._done = False
+        self.offset = array.start
+        self.dim = dim
+        self.array = array
+        
+    def setitem(self, elem):
+        self.array.setitem(self.offset, elem)
+
+    def getitem(self):
+        return self.array.getitem(self.offset)
+
+    @jit.unroll_safe
+    def next(self):
+        for i in range(len(self.shape) - 1, -1, -1):
+            if self.indices[i] < self.shape[i] - 1:
+                if i == self.dim:
+                    self.first_line = False
+                self.indices[i] += 1
+                self.offset += self.strides[i]
+                break
+            else:
+                if i == self.dim:
+                    self.first_line = True
+                self.indices[i] = 0
+                self.offset -= self.backstrides[i]
+        else:
+            self._done = True
+
+    def done(self):
+        return self._done
+
+def int_w(space, w_obj):
+    try:
+        return space.int_w(space.index(w_obj))
+    except OperationError:
+        return space.int_w(space.int(w_obj))
+
+class BaseConcreteArray(base.BaseArrayImplementation):
+    start = 0
+    parent = None
+    
+    def get_shape(self):
+        return self.shape
+
+    def getitem(self, index):
+        return self.dtype.getitem(self, index)
+
+    def setitem(self, index, value):
+        self.dtype.setitem(self, index, value)
+
+    def setslice(self, space, arr):
+        impl = arr.implementation
+        if impl.is_scalar():
+            self.fill(impl.get_scalar_value())
+            return
+        shape = shape_agreement(space, self.shape, arr)
+        if impl.storage == self.storage:
+            impl = impl.copy()
+        loop.setslice(shape, self, impl)
+
+    def get_size(self):
+        return self.size // self.dtype.itemtype.get_element_size()
+
+    def reshape(self, space, new_shape):
+        # Since we got to here, prod(new_shape) == self.size
+        new_strides = None
+        if self.size > 0:
+            new_strides = calc_new_strides(new_shape, self.shape,
+                                           self.strides, self.order)
+        if new_strides:
+            # We can create a view, strides somehow match up.
+            ndims = len(new_shape)
+            new_backstrides = [0] * ndims
+            for nd in range(ndims):
+                new_backstrides[nd] = (new_shape[nd] - 1) * new_strides[nd]
+            return SliceArray(self.start, new_strides, new_backstrides,
+                              new_shape, self)
+        else:
+            return None
+
+    # -------------------- applevel get/setitem -----------------------
+
+    @jit.unroll_safe
+    def _lookup_by_index(self, space, view_w):
+        item = self.start
+        for i, w_index in enumerate(view_w):
+            if space.isinstance_w(w_index, space.w_slice):
+                raise IndexError
+            idx = int_w(space, w_index)
+            if idx < 0:
+                idx = self.shape[i] + idx
+            if idx < 0 or idx >= self.shape[i]:
+                raise operationerrfmt(space.w_IndexError,
+                      "index (%d) out of range (0<=index<%d", i, self.shape[i],
+                )
+            item += idx * self.strides[i]
+        return item
+
+    def _single_item_index(self, space, w_idx):
+        """ Return an index of single item if possible, otherwise raises
+        IndexError
+        """
+        if (space.isinstance_w(w_idx, space.w_str) or
+            space.isinstance_w(w_idx, space.w_slice) or
+            space.is_w(w_idx, space.w_None)):
+            raise IndexError
+        shape_len = len(self.shape)
+        if shape_len == 0:
+            raise OperationError(space.w_IndexError, space.wrap(
+                "0-d arrays can't be indexed"))
+        if space.isinstance_w(w_idx, space.w_tuple):
+            view_w = space.fixedview(w_idx)
+            if len(view_w) < shape_len:
+                raise IndexError
+            if len(view_w) > shape_len:
+                # we can allow for one extra None
+                count = len(view_w)
+                for w_item in view_w:
+                    if space.is_w(w_item, space.w_None):
+                        count -= 1
+                if count == shape_len:
+                    raise IndexError # but it's still not a single item
+                raise OperationError(space.w_IndexError,
+                                     space.wrap("invalid index"))
+            return self._lookup_by_index(space, view_w)
+        if shape_len > 1:
+            raise IndexError
+        idx = int_w(space, w_idx)
+        return self._lookup_by_index(space, [space.wrap(idx)])
+
+    @jit.unroll_safe
+    def _prepare_slice_args(self, space, w_idx):
+        if space.isinstance_w(w_idx, space.w_str):
+            idx = space.str_w(w_idx)
+            dtype = self.dtype
+            if not dtype.is_record_type() or idx not in dtype.fields:
+                raise OperationError(space.w_ValueError, space.wrap(
+                    "field named %s not defined" % idx))
+            return RecordChunk(idx)
+        if (space.isinstance_w(w_idx, space.w_int) or
+            space.isinstance_w(w_idx, space.w_slice)):
+            return Chunks([Chunk(*space.decode_index4(w_idx, self.shape[0]))])
+        elif space.is_w(w_idx, space.w_None):
+            return Chunks([NewAxisChunk()])
+        result = []
+        i = 0
+        for w_item in space.fixedview(w_idx):
+            if space.is_w(w_item, space.w_None):
+                result.append(NewAxisChunk())
+            else:
+                result.append(Chunk(*space.decode_index4(w_item,
+                                                         self.shape[i])))
+                i += 1
+        return Chunks(result)
+
+    def descr_getitem(self, space, w_index):
+        try:
+            item = self._single_item_index(space, w_index)
+            return self.getitem(item)
+        except IndexError:
+            # not a single result
+            chunks = self._prepare_slice_args(space, w_index)
+            return chunks.apply(self)
+
+    def descr_setitem(self, space, w_index, w_value):
+        try:
+            item = self._single_item_index(space, w_index)
+            self.setitem(item, self.dtype.coerce(space, w_value))
+        except IndexError:
+            w_value = convert_to_array(space, w_value)
+            chunks = self._prepare_slice_args(space, w_index)
+            view = chunks.apply(self)
+            view.implementation.setslice(space, w_value)
+
+    def transpose(self):
+        if len(self.shape) < 2:
+            return self
+        strides = []
+        backstrides = []
+        shape = []
+        for i in range(len(self.shape) - 1, -1, -1):
+            strides.append(self.strides[i])
+            backstrides.append(self.backstrides[i])
+            shape.append(self.shape[i])
+        return SliceArray(self.start, strides,
+                          backstrides, shape, self)
+
+    def copy(self):
+        strides, backstrides = support.calc_strides(self.shape, self.dtype,
+                                                    self.order)
+        impl = ConcreteArray(self.shape, self.dtype, self.order, strides,
+                             backstrides)
+        return loop.setslice(self.shape, impl, self)
+
+    def create_axis_iter(self, shape, dim):
+        return AxisIterator(self, shape, dim)
+
+    def create_dot_iter(self, shape, skip):
+        r = calculate_dot_strides(self.strides, self.backstrides,
+                                  shape, skip)
+        return MultiDimViewIterator(self, self.start, r[0], r[1], shape)
+
+    def swapaxes(self, axis1, axis2):
+        shape = self.shape[:]
+        strides = self.strides[:]
+        backstrides = self.backstrides[:]
+        shape[axis1], shape[axis2] = shape[axis2], shape[axis1]   
+        strides[axis1], strides[axis2] = strides[axis2], strides[axis1]
+        backstrides[axis1], backstrides[axis2] = backstrides[axis2], backstrides[axis1] 
+        return W_NDimArray.new_slice(self.start, strides, 
+                                     backstrides, shape, self)
+
+    def get_storage_as_int(self, space):
+        return rffi.cast(lltype.Signed, self.storage)
+
+class ConcreteArray(BaseConcreteArray):
+    def __init__(self, shape, dtype, order, strides, backstrides):
+        self.shape = shape
+        self.size = support.product(shape) * dtype.get_size()
+        self.storage = dtype.itemtype.malloc(self.size)
+        self.order = order
+        self.dtype = dtype
+        self.strides = strides
+        self.backstrides = backstrides
+
+    def create_iter(self, shape):
+        if shape == self.shape:
+            return ConcreteArrayIterator(self)
+        r = calculate_broadcast_strides(self.strides, self.backstrides,
+                                        self.shape, shape)
+        return MultiDimViewIterator(self, 0, r[0], r[1], shape)
+
+    def fill(self, box):
+        self.dtype.fill(self.storage, box, 0, self.size)
+
+    def __del__(self):
+        free_raw_storage(self.storage, track_allocation=False)
+
+    def set_shape(self, space, new_shape):
+        strides, backstrides = support.calc_strides(new_shape, self.dtype,
+                                                    self.order)
+        return SliceArray(0, strides, backstrides, new_shape, self)
+
+class SliceArray(BaseConcreteArray):
+    def __init__(self, start, strides, backstrides, shape, parent, dtype=None):
+        self.strides = strides
+        self.backstrides = backstrides
+        self.shape = shape
+        if isinstance(parent, SliceArray):
+            parent = parent.parent # one level only
+        self.parent = parent
+        self.storage = parent.storage
+        self.order = parent.order
+        if dtype is None:
+            dtype = parent.dtype
+        self.dtype = dtype
+        self.size = support.product(shape) * self.dtype.itemtype.get_element_size()
+        self.start = start
+
+    def fill(self, box):
+        loop.fill(self, box.convert_to(self.dtype))
+
+    def create_iter(self, shape):
+        if shape != self.shape:
+            r = calculate_broadcast_strides(self.strides, self.backstrides,
+                                            self.shape, shape)
+            return MultiDimViewIterator(self.parent,
+                                        self.start, r[0], r[1], shape)
+        if len(self.shape) == 1:
+            return OneDimViewIterator(self)
+        return MultiDimViewIterator(self.parent, self.start, self.strides,
+                                    self.backstrides, self.shape)
+
+    def set_shape(self, space, new_shape):
+        if len(self.shape) < 2 or self.size == 0:
+            # TODO: this code could be refactored into calc_strides
+            # but then calc_strides would have to accept a stepping factor
+            strides = []
+            backstrides = []
+            dtype = self.dtype
+            s = self.strides[0] // dtype.get_size()
+            if self.order == 'C':
+                new_shape.reverse()
+            for sh in new_shape:
+                strides.append(s * dtype.get_size())
+                backstrides.append(s * (sh - 1) * dtype.get_size())
+                s *= max(1, sh)
+            if self.order == 'C':
+                strides.reverse()
+                backstrides.reverse()
+                new_shape.reverse()
+            return SliceArray(self.start, strides, backstrides, new_shape,
+                              self)
+        new_strides = calc_new_strides(new_shape, self.shape, self.strides,
+                                       self.order)
+        if new_strides is None:
+            raise OperationError(space.w_AttributeError, space.wrap(
+                          "incompatible shape for a non-contiguous array"))
+        new_backstrides = [0] * len(new_shape)
+        for nd in range(len(new_shape)):
+            new_backstrides[nd] = (new_shape[nd] - 1) * new_strides[nd]
+        return SliceArray(self.start, new_strides, new_backstrides, new_shape,
+                          self)
diff --git a/pypy/module/micronumpy/arrayimpl/scalar.py b/pypy/module/micronumpy/arrayimpl/scalar.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/micronumpy/arrayimpl/scalar.py
@@ -0,0 +1,90 @@
+
+from pypy.module.micronumpy.arrayimpl import base
+from pypy.module.micronumpy.base import W_NDimArray
+from pypy.module.micronumpy import support
+from pypy.interpreter.error import OperationError
+
+class ScalarIterator(base.BaseArrayIterator):
+    def __init__(self, v):
+        self.v = v
+
+    def next(self):
+        pass
+
+    def getitem(self):
+        return self.v
+
+    def setitem(self, v):
+        raise Exception("Don't call setitem on scalar iterators")
+
+    def done(self):
+        raise Exception("should not call done on scalar")
+
+    def reset(self):
+        pass
+
+class Scalar(base.BaseArrayImplementation):
+    def __init__(self, dtype, value=None):
+        self.dtype = dtype
+        self.value = value
+
+    def is_scalar(self):
+        return True
+
+    def get_shape(self):
+        return []
+
+    def create_iter(self, shape):
+        return ScalarIterator(self.value)
+
+    def get_scalar_value(self):
+        return self.value
+
+    def set_scalar_value(self, w_val):
+        self.value = w_val.convert_to(self.dtype)
+
+    def copy(self):
+        scalar = Scalar(self.dtype)
+        scalar.value = self.value
+        return scalar
+
+    def get_size(self):
+        return 1
+
+    def transpose(self):
+        return self
+
+    def descr_getitem(self, space, w_idx):
+        raise OperationError(space.w_IndexError,
+                             space.wrap("scalars cannot be indexed"))
+
+    def descr_setitem(self, space, w_idx, w_val):
+        raise OperationError(space.w_IndexError,
+                             space.wrap("scalars cannot be indexed"))
+        
+    def set_shape(self, space, new_shape):
+        if not new_shape:
+            return self
+        if support.product(new_shape) == 1:
+            arr = W_NDimArray.from_shape(new_shape, self.dtype)
+            arr_iter = arr.create_iter(new_shape)
+            arr_iter.setitem(self.value)
+            return arr.implementation
+        raise OperationError(space.w_ValueError, space.wrap(
+            "total size of the array must be unchanged"))
+
+    def reshape(self, space, new_shape):
+        return self.set_shape(space, new_shape)
+        
+    def create_axis_iter(self, shape, dim):
+        raise Exception("axis iter should not happen on scalar")
+
+    def swapaxes(self, axis1, axis2):
+        raise Exception("should not be called")
+
+    def fill(self, w_value):
+        self.value = w_value
+
+    def get_storage_as_int(self, space):
+        raise OperationError(space.w_ValueError,
+                             space.wrap("scalars have no address"))
diff --git a/pypy/module/micronumpy/arrayimpl/voidbox.py b/pypy/module/micronumpy/arrayimpl/voidbox.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/micronumpy/arrayimpl/voidbox.py
@@ -0,0 +1,11 @@
+
+from pypy.module.micronumpy.arrayimpl.base import BaseArrayImplementation
+from pypy.rlib.rawstorage import free_raw_storage, alloc_raw_storage
+
+class VoidBoxStorage(BaseArrayImplementation):
+    def __init__(self, size, dtype):
+        self.storage = alloc_raw_storage(size)
+        self.dtype = dtype
+
+    def __del__(self):
+        free_raw_storage(self.storage)
diff --git a/pypy/module/micronumpy/base.py b/pypy/module/micronumpy/base.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/micronumpy/base.py
@@ -0,0 +1,50 @@
+
+from pypy.interpreter.baseobjspace import Wrappable
+from pypy.tool.pairtype import extendabletype
+from pypy.module.micronumpy.support import calc_strides
+
+class W_NDimArray(Wrappable):
+    __metaclass__ = extendabletype
+
+    def __init__(self, implementation):
+        self.implementation = implementation
+    
+    @staticmethod
+    def from_shape(shape, dtype, order='C'):
+        from pypy.module.micronumpy.arrayimpl import concrete
+
+        assert shape
+        strides, backstrides = calc_strides(shape, dtype, order)
+        impl = concrete.ConcreteArray(shape, dtype, order, strides,
+                                      backstrides)
+        return W_NDimArray(impl)
+
+    @staticmethod
+    def new_slice(offset, strides, backstrides, shape, parent, dtype=None):
+        from pypy.module.micronumpy.arrayimpl import concrete
+
+        impl = concrete.SliceArray(offset, strides, backstrides, shape, parent,
+                                   dtype)
+        return W_NDimArray(impl)
+
+    @staticmethod
+    def new_scalar(space, dtype, w_val=None):
+        from pypy.module.micronumpy.arrayimpl import scalar
+
+        if w_val is not None:
+            w_val = dtype.coerce(space, w_val)
+        return W_NDimArray(scalar.Scalar(dtype, w_val))
+
+def convert_to_array(space, w_obj):
+    from pypy.module.micronumpy.interp_numarray import array
+    from pypy.module.micronumpy import interp_ufuncs
+    
+    if isinstance(w_obj, W_NDimArray):
+        return w_obj
+    elif space.issequence_w(w_obj):
+        # Convert to array.
+        return array(space, w_obj, w_order=None)
+    else:
+        # If it's a scalar
+        dtype = interp_ufuncs.find_dtype_for_scalar(space, w_obj)
+        return W_NDimArray.new_scalar(space, dtype, w_obj)
diff --git a/pypy/module/micronumpy/dot.py b/pypy/module/micronumpy/dot.py
--- a/pypy/module/micronumpy/dot.py
+++ b/pypy/module/micronumpy/dot.py
@@ -1,85 +1,23 @@
-from pypy.module.micronumpy.strides import calculate_dot_strides
 from pypy.interpreter.error import OperationError
-from pypy.module.micronumpy.interp_iter import ViewIterator
-from pypy.rlib import jit
-
-def dot_printable_location(shapelen):
-    return 'numpy dot [%d]' % shapelen
-
-dot_driver = jit.JitDriver(
-    greens=['shapelen'],
-    reds=['lefti', 'righti', 'outi', 'result', 'right', 'dtype',
-          'left'],
-    get_printable_location=dot_printable_location,
-    name='dot',
-)
 
 def match_dot_shapes(space, left, right):
-    my_critical_dim_size = left.shape[-1]
-    right_critical_dim_size = right.shape[0]
+    left_shape = left.get_shape()
+    right_shape = right.get_shape()
+    my_critical_dim_size = left_shape[-1]
+    right_critical_dim_size = right_shape[0]
     right_critical_dim = 0
     out_shape = []
-    if len(right.shape) > 1:
-        right_critical_dim = len(right.shape) - 2
-        right_critical_dim_size = right.shape[right_critical_dim]
+    if len(right_shape) > 1:
+        right_critical_dim = len(right_shape) - 2
+        right_critical_dim_size = right_shape[right_critical_dim]
         assert right_critical_dim >= 0
-        out_shape += left.shape[:-1] + \
-                     right.shape[0:right_critical_dim] + \
-                     right.shape[right_critical_dim + 1:]
-    elif len(right.shape) > 0:
+        out_shape += left_shape[:-1] + \
+                     right_shape[0:right_critical_dim] + \
+                     right_shape[right_critical_dim + 1:]
+    elif len(right_shape) > 0:
         #dot does not reduce for scalars
-        out_shape += left.shape[:-1]
+        out_shape += left_shape[:-1]
     if my_critical_dim_size != right_critical_dim_size:
         raise OperationError(space.w_ValueError, space.wrap(
                                         "objects are not aligned"))
     return out_shape, right_critical_dim
-
-def multidim_dot(space, left, right, result, dtype, right_critical_dim):
-    ''' assumes left, right are concrete arrays
-    given left.shape == [3, 5, 7],
-          right.shape == [2, 7, 4]
-    then
-     result.shape == [3, 5, 2, 4]
-     broadcast shape should be [3, 5, 2, 7, 4]
-     result should skip dims 3 which is len(result_shape) - 1
-        (note that if right is 1d, result should 
-                  skip len(result_shape))
-     left should skip 2, 4 which is a.ndims-1 + range(right.ndims)
-          except where it==(right.ndims-2)
-     right should skip 0, 1
-    '''
-    broadcast_shape = left.shape[:-1] + right.shape
-    shapelen = len(broadcast_shape)
-    left_skip = [len(left.shape) - 1 + i for i in range(len(right.shape))
-                                         if i != right_critical_dim]
-    right_skip = range(len(left.shape) - 1)
-    result_skip = [len(result.shape) - (len(right.shape) > 1)]
-    _r = calculate_dot_strides(result.strides, result.backstrides,
-                                  broadcast_shape, result_skip)
-    outi = ViewIterator(result.start, _r[0], _r[1], broadcast_shape)
-    _r = calculate_dot_strides(left.strides, left.backstrides,
-                                  broadcast_shape, left_skip)
-    lefti = ViewIterator(left.start, _r[0], _r[1], broadcast_shape)
-    _r = calculate_dot_strides(right.strides, right.backstrides,
-                                  broadcast_shape, right_skip)
-    righti = ViewIterator(right.start, _r[0], _r[1], broadcast_shape)
-    while not outi.done():
-        dot_driver.jit_merge_point(left=left,
-                                   right=right,
-                                   shapelen=shapelen,
-                                   lefti=lefti,
-                                   righti=righti,
-                                   outi=outi,
-                                   result=result,
-                                   dtype=dtype,
-                                  )
-        lval = left.getitem(lefti.offset).convert_to(dtype) 
-        rval = right.getitem(righti.offset).convert_to(dtype) 
-        outval = result.getitem(outi.offset).convert_to(dtype) 
-        v = dtype.itemtype.mul(lval, rval)
-        value = dtype.itemtype.add(v, outval).convert_to(dtype)
-        result.setitem(outi.offset, value)
-        outi = outi.next(shapelen)
-        righti = righti.next(shapelen)
-        lefti = lefti.next(shapelen)
-    return result
diff --git a/pypy/module/micronumpy/interp_arrayops.py b/pypy/module/micronumpy/interp_arrayops.py
--- a/pypy/module/micronumpy/interp_arrayops.py
+++ b/pypy/module/micronumpy/interp_arrayops.py
@@ -1,30 +1,12 @@
 
-from pypy.module.micronumpy.interp_numarray import convert_to_array,\
-     VirtualArray
-from pypy.module.micronumpy import signature
+from pypy.module.micronumpy.base import convert_to_array, W_NDimArray
+from pypy.module.micronumpy import loop, interp_ufuncs
+from pypy.module.micronumpy.iter import Chunk, Chunks
+from pypy.module.micronumpy.strides import shape_agreement
+from pypy.interpreter.error import OperationError, operationerrfmt
+from pypy.interpreter.gateway import unwrap_spec
 
-class WhereArray(VirtualArray):
-    def __init__(self, space, arr, x, y):
-        self.arr = arr
-        self.x = x
-        self.y = y
-        VirtualArray.__init__(self, 'where', arr.shape[:],
-                              x.find_dtype())
-
-    def create_sig(self):
-        if self.forced_result is not None:
-            return self.forced_result.create_sig()
-        return signature.WhereSignature(self.res_dtype, self.arr.find_dtype(),
-                                        self.arr.create_sig(),
-                                        self.x.create_sig(),
-                                        self.y.create_sig())
-
-    def _del_sources(self):
-        self.arr = None
-        self.x = None
-        self.y = None
-
-def where(space, w_arr, w_x, w_y):
+def where(space, w_arr, w_x=None, w_y=None):
     """where(condition, [x, y])
 
     Return elements, either from `x` or `y`, depending on `condition`.
@@ -84,7 +66,87 @@
     
     NOTE: support for not passing x and y is unsupported
     """
+    if space.is_w(w_y, space.w_None):
+        if space.is_w(w_x, space.w_None):
+            raise OperationError(space.w_NotImplementedError, space.wrap(
+                "1-arg where unsupported right now"))
+        raise OperationError(space.w_ValueError, space.wrap(
+            "Where should be called with either 1 or 3 arguments"))
     arr = convert_to_array(space, w_arr)
     x = convert_to_array(space, w_x)
     y = convert_to_array(space, w_y)
-    return WhereArray(space, arr, x, y)
+    if x.is_scalar() and y.is_scalar() and arr.is_scalar():
+        if arr.get_dtype().itemtype.bool(arr.get_scalar_value()):
+            return x
+        return y
+    dtype = interp_ufuncs.find_binop_result_dtype(space, x.get_dtype(),
+                                                  y.get_dtype())
+    shape = shape_agreement(space, arr.get_shape(), x)
+    shape = shape_agreement(space, shape, y)
+    out = W_NDimArray.from_shape(shape, dtype)
+    return loop.where(out, shape, arr, x, y, dtype)
+
+def dot(space, w_obj1, w_obj2):
+    w_arr = convert_to_array(space, w_obj1)
+    if w_arr.is_scalar():
+        return convert_to_array(space, w_obj2).descr_dot(space, w_arr)
+    return w_arr.descr_dot(space, w_obj2)
+
+
+ at unwrap_spec(axis=int)
+def concatenate(space, w_args, axis=0):
+    args_w = space.listview(w_args)
+    if len(args_w) == 0:
+        raise OperationError(space.w_ValueError, space.wrap("need at least one array to concatenate"))
+    args_w = [convert_to_array(space, w_arg) for w_arg in args_w]
+    dtype = args_w[0].get_dtype()
+    shape = args_w[0].get_shape()[:]
+    if len(shape) <= axis:
+        raise operationerrfmt(space.w_IndexError, "axis %d out of bounds [0, %d)", axis, len(shape))
+    for arr in args_w[1:]:
+        dtype = interp_ufuncs.find_binop_result_dtype(space, dtype,
+                                                      arr.get_dtype())
+        if len(arr.get_shape()) <= axis:
+            raise operationerrfmt(space.w_IndexError, "axis %d out of bounds [0, %d)", axis, len(shape))
+        for i, axis_size in enumerate(arr.get_shape()):
+            if len(arr.get_shape()) != len(shape) or (i != axis and axis_size != shape[i]):
+                raise OperationError(space.w_ValueError, space.wrap(
+                    "all the input arrays must have same number of dimensions"))
+            elif i == axis:
+                shape[i] += axis_size
+    res = W_NDimArray.from_shape(shape, dtype, 'C')
+    chunks = [Chunk(0, i, 1, i) for i in shape]
+    axis_start = 0
+    for arr in args_w:
+        chunks[axis] = Chunk(axis_start, axis_start + arr.get_shape()[axis], 1,
+                             arr.get_shape()[axis])
+        Chunks(chunks).apply(res.implementation).implementation.setslice(space, arr)
+        axis_start += arr.get_shape()[axis]
+    return res
+
+ at unwrap_spec(repeats=int)
+def repeat(space, w_arr, repeats, w_axis=None):
+    arr = convert_to_array(space, w_arr)
+    if space.is_w(w_axis, space.w_None):
+        arr = arr.descr_flatten(space)
+        orig_size = arr.get_shape()[0]
+        shape = [arr.get_shape()[0] * repeats]
+        res = W_NDimArray.from_shape(shape, arr.get_dtype())
+        for i in range(repeats):
+            Chunks([Chunk(i, shape[0] - repeats + i, repeats,
+                          orig_size)]).apply(res.implementation).implementation.setslice(space, arr)
+    else:
+        axis = space.int_w(w_axis)
+        shape = arr.get_shape()[:]
+        chunks = [Chunk(0, i, 1, i) for i in shape]
+        orig_size = shape[axis]
+        shape[axis] *= repeats
+        res = W_NDimArray.from_shape(shape, arr.get_dtype())
+        for i in range(repeats):
+            chunks[axis] = Chunk(i, shape[axis] - repeats + i, repeats,
+                                 orig_size)
+            Chunks(chunks).apply(res.implementation).implementation.setslice(space, arr)
+    return res
+
+def count_nonzero(space, w_obj):
+    return space.wrap(loop.count_all_true(convert_to_array(space, w_obj)))
diff --git a/pypy/module/micronumpy/interp_boxes.py b/pypy/module/micronumpy/interp_boxes.py
--- a/pypy/module/micronumpy/interp_boxes.py
+++ b/pypy/module/micronumpy/interp_boxes.py
@@ -8,6 +8,7 @@
 from pypy.objspace.std.inttype import int_typedef
 from pypy.rlib.rarithmetic import LONG_BIT
 from pypy.tool.sourcetools import func_with_new_name
+from pypy.module.micronumpy.arrayimpl.voidbox import VoidBoxStorage
 
 MIXIN_32 = (int_typedef,) if LONG_BIT == 32 else ()
 MIXIN_64 = (int_typedef,) if LONG_BIT == 64 else ()
@@ -33,7 +34,6 @@
     def convert_to(self, dtype):
         return dtype.box(self.value)
 
-
 class W_GenericBox(Wrappable):
     _attrs_ = ()
 
@@ -142,7 +142,6 @@
     def item(self, space):
         return self.get_dtype(space).itemtype.to_builtin_type(space, self)
 
-
 class W_BoolBox(W_GenericBox, PrimitiveBox):
     descr__new__, _get_dtype = new_dtype_getter("bool")
 
@@ -246,11 +245,10 @@
 
 class W_StringBox(W_CharacterBox):
     def descr__new__string_box(space, w_subtype, w_arg):
-        from pypy.module.micronumpy.interp_numarray import W_NDimArray
         from pypy.module.micronumpy.interp_dtype import new_string_dtype
 
         arg = space.str_w(space.str(w_arg))
-        arr = W_NDimArray([1], new_string_dtype(space, len(arg)))
+        arr = VoidBoxStorage(len(arg), new_string_dtype(space, len(arg)))
         for i in range(len(arg)):
             arr.storage[i] = arg[i]
         return W_StringBox(arr, 0, arr.dtype)
@@ -258,11 +256,11 @@
 
 class W_UnicodeBox(W_CharacterBox):
     def descr__new__unicode_box(space, w_subtype, w_arg):
-        from pypy.module.micronumpy.interp_numarray import W_NDimArray
         from pypy.module.micronumpy.interp_dtype import new_unicode_dtype
 
         arg = space.unicode_w(unicode_from_object(space, w_arg))
-        arr = W_NDimArray([1], new_unicode_dtype(space, len(arg)))
+        # XXX size computations, we need tests anyway
+        arr = VoidBoxStorage(len(arg), new_unicode_dtype(space, len(arg)))
         # XXX not this way, we need store
         #for i in range(len(arg)):
         #    arr.storage[i] = arg[i]
diff --git a/pypy/module/micronumpy/interp_dtype.py b/pypy/module/micronumpy/interp_dtype.py
--- a/pypy/module/micronumpy/interp_dtype.py
+++ b/pypy/module/micronumpy/interp_dtype.py
@@ -18,6 +18,12 @@
 STRINGLTR = 'S'
 UNICODELTR = 'U'
 
+def decode_w_dtype(space, w_dtype):
+    if w_dtype is None or space.is_w(w_dtype, space.w_None):
+        return None
+    return space.interp_w(W_Dtype,
+          space.call_function(space.gettypefor(W_Dtype), w_dtype))
+
 class W_Dtype(Wrappable):
     _immutable_fields_ = ["itemtype", "num", "kind"]
 
diff --git a/pypy/module/micronumpy/interp_flatiter.py b/pypy/module/micronumpy/interp_flatiter.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/micronumpy/interp_flatiter.py
@@ -0,0 +1,83 @@
+
+from pypy.module.micronumpy.base import W_NDimArray, convert_to_array
+from pypy.module.micronumpy import loop
+from pypy.module.micronumpy.arrayimpl.base import BaseArrayImplementation
+from pypy.interpreter.error import OperationError
+
+class FakeArrayImplementation(BaseArrayImplementation):
+    """ The sole purpose of this class is to W_FlatIterator can behave
+    like a real array for descr_eq and friends
+    """
+    def __init__(self, base):
+        self.base = base
+        self.dtype = base.get_dtype()
+        self.shape = [base.get_size()]
+
+    def get_shape(self):
+        return self.shape
+
+    def create_iter(self, shape=None):
+        return self.base.create_iter()
+
+class W_FlatIterator(W_NDimArray):
+    def __init__(self, arr):
+        self.base = arr
+        # this is needed to support W_NDimArray interface
+        self.implementation = FakeArrayImplementation(self.base)
+        self.reset()
+
+    def reset(self):
+        self.iter = self.base.create_iter()
+        self.index = 0
+
+    def descr_len(self, space):
+        return space.wrap(self.base.get_size())
+
+    def descr_next(self, space):
+        if self.iter.done():
+            raise OperationError(space.w_StopIteration, space.w_None)
+        w_res = self.iter.getitem()
+        self.iter.next()
+        self.index += 1
+        return w_res
+
+    def descr_index(self, space):
+        return space.wrap(self.index)
+
+    def descr_coords(self, space):
+        coords = self.base.to_coords(space, space.wrap(self.index))
+        return space.newtuple([space.wrap(c) for c in coords])
+
+    def descr_getitem(self, space, w_idx):
+        if not (space.isinstance_w(w_idx, space.w_int) or
+            space.isinstance_w(w_idx, space.w_slice)):
+            raise OperationError(space.w_IndexError,
+                                 space.wrap('unsupported iterator index'))
+        self.reset()
+        base = self.base
+        start, stop, step, length = space.decode_index4(w_idx, base.get_size())
+        base_iter = base.create_iter()
+        base_iter.next_skip_x(start)
+        if length == 1:
+            return base_iter.getitem()
+        res = W_NDimArray.from_shape([length], base.get_dtype(),
+                                     base.get_order())
+        return loop.flatiter_getitem(res, base_iter, step)
+
+    def descr_setitem(self, space, w_idx, w_value):
+        if not (space.isinstance_w(w_idx, space.w_int) or
+            space.isinstance_w(w_idx, space.w_slice)):
+            raise OperationError(space.w_IndexError,
+                                 space.wrap('unsupported iterator index'))
+        base = self.base
+        start, stop, step, length = space.decode_index4(w_idx, base.get_size())
+        arr = convert_to_array(space, w_value)
+        loop.flatiter_setitem(self.base, arr, start, step, length)
+
+    def descr_iter(self):
+        return self
+
+    def descr_base(self, space):
+        return space.wrap(self.base)
+
+# typedef is in interp_numarray, so we see the additional arguments
diff --git a/pypy/module/micronumpy/interp_iter.py b/pypy/module/micronumpy/interp_iter.py
deleted file mode 100644
--- a/pypy/module/micronumpy/interp_iter.py
+++ /dev/null
@@ -1,359 +0,0 @@
-
-from pypy.rlib import jit
-from pypy.rlib.objectmodel import instantiate
-from pypy.module.micronumpy.strides import calculate_broadcast_strides,\
-     calculate_slice_strides, calculate_dot_strides, enumerate_chunks
-
-""" This is a mini-tutorial on iterators, strides, and
-memory layout. It assumes you are familiar with the terms, see
-http://docs.scipy.org/doc/numpy/reference/arrays.ndarray.html
-for a more gentle introduction.
-
-Given an array x: x.shape == [5,6],
-
-At which byte in x.data does the item x[3,4] begin?
-if x.strides==[1,5]:
-    pData = x.pData + (x.start + 3*1 + 4*5)*sizeof(x.pData[0])
-    pData = x.pData + (x.start + 24) * sizeof(x.pData[0])
-so the offset of the element is 24 elements after the first
-
-What is the next element in x after coordinates [3,4]?
-if x.order =='C':
-   next == [3,5] => offset is 28
-if x.order =='F':
-   next == [4,4] => offset is 24
-so for the strides [1,5] x is 'F' contiguous
-likewise, for the strides [6,1] x would be 'C' contiguous.
-
-Iterators have an internal representation of the current coordinates
-(indices), the array, strides, and backstrides. A short digression to
-explain backstrides: what is the coordinate and offset after [3,5] in
-the example above?
-if x.order == 'C':
-   next == [4,0] => offset is 4
-if x.order == 'F':
-   next == [4,5] => offset is 25
-Note that in 'C' order we stepped BACKWARDS 24 while 'overflowing' a
-shape dimension
-  which is back 25 and forward 1,
-  which is x.strides[1] * (x.shape[1] - 1) + x.strides[0]
-so if we precalculate the overflow backstride as 
-[x.strides[i] * (x.shape[i] - 1) for i in range(len(x.shape))]
-we can go faster.
-All the calculations happen in next()
-
-next_skip_x() tries to do the iteration for a number of steps at once,
-but then we cannot gaurentee that we only overflow one single shape 
-dimension, perhaps we could overflow times in one big step.
-"""
-
-# structures to describe slicing
-
-class BaseChunk(object):
-    pass
-
-class RecordChunk(BaseChunk):
-    def __init__(self, name):
-        self.name = name
-
-    def apply(self, arr):
-        from pypy.module.micronumpy.interp_numarray import W_NDimSlice
-
-        arr = arr.get_concrete()
-        ofs, subdtype = arr.dtype.fields[self.name]
-        # strides backstrides are identical, ofs only changes start
-        return W_NDimSlice(arr.start + ofs, arr.strides[:], arr.backstrides[:],
-                           arr.shape[:], arr, subdtype)
-
-class Chunks(BaseChunk):
-    def __init__(self, l):
-        self.l = l
-
-    @jit.unroll_safe
-    def extend_shape(self, old_shape):
-        shape = []
-        i = -1
-        for i, c in enumerate_chunks(self.l):
-            if c.step != 0:
-                shape.append(c.lgt)
-        s = i + 1
-        assert s >= 0
-        return shape[:] + old_shape[s:]
-
-    def apply(self, arr):
-        from pypy.module.micronumpy.interp_numarray import W_NDimSlice,\
-             VirtualSlice, ConcreteArray
-
-        shape = self.extend_shape(arr.shape)
-        if not isinstance(arr, ConcreteArray):
-            return VirtualSlice(arr, self, shape)
-        r = calculate_slice_strides(arr.shape, arr.start, arr.strides,
-                                    arr.backstrides, self.l)
-        _, start, strides, backstrides = r
-        return W_NDimSlice(start, strides[:], backstrides[:],
-                           shape[:], arr)
-
-
-class Chunk(BaseChunk):
-    axis_step = 1
-
-    def __init__(self, start, stop, step, lgt):
-        self.start = start
-        self.stop = stop
-        self.step = step
-        self.lgt = lgt
-
-    def __repr__(self):
-        return 'Chunk(%d, %d, %d, %d)' % (self.start, self.stop, self.step,
-                                          self.lgt)
-
-class NewAxisChunk(Chunk):
-    start = 0
-    stop = 1
-    step = 1
-    lgt = 1
-    axis_step = 0
-
-    def __init__(self):
-        pass
-
-class BaseTransform(object):
-    pass
-
-class ViewTransform(BaseTransform):
-    def __init__(self, chunks):
-        # 4-tuple specifying slicing
-        self.chunks = chunks
-
-class BroadcastTransform(BaseTransform):
-    def __init__(self, res_shape):
-        self.res_shape = res_shape
-
-
-class BaseIterator(object):
-    def next(self, shapelen):
-        raise NotImplementedError
-
-    def done(self):
-        raise NotImplementedError
-
-    def apply_transformations(self, arr, transformations):
-        v = self
-        if transformations is not None:
-            for transform in transformations:
-                v = v.transform(arr, transform)
-        return v
-
-    def transform(self, arr, t):
-        raise NotImplementedError
-
-class ArrayIterator(BaseIterator):
-    def __init__(self, size, element_size):
-        self.offset = 0
-        self.size = size
-        self.element_size = element_size
-
-    def next(self, shapelen):
-        return self.next_skip_x(1)
-
-    def next_skip_x(self, x):
-        arr = instantiate(ArrayIterator)
-        arr.size = self.size
-        arr.offset = self.offset + x * self.element_size
-        arr.element_size = self.element_size
-        return arr
-
-    def next_no_increase(self, shapelen):
-        # a hack to make JIT believe this is always virtual
-        return self.next_skip_x(0)
-
-    def done(self):
-        return self.offset >= self.size
-
-    def transform(self, arr, t):
-        return ViewIterator(arr.start, arr.strides, arr.backstrides,
-                            arr.shape).transform(arr, t)
-
-class OneDimIterator(BaseIterator):
-    def __init__(self, start, step, stop):
-        self.offset = start
-        self.step = step
-        self.size = stop * step + start
-
-    def next(self, shapelen):
-        arr = instantiate(OneDimIterator)
-        arr.size = self.size
-        arr.step = self.step
-        arr.offset = self.offset + self.step
-        return arr
-
-    def done(self):
-        return self.offset == self.size
-
-class ViewIterator(BaseIterator):
-    def __init__(self, start, strides, backstrides, shape):
-        self.offset  = start
-        self._done   = False
-        self.strides = strides
-        self.backstrides = backstrides
-        self.res_shape = shape
-        self.indices = [0] * len(self.res_shape)
-
-    def transform(self, arr, t):
-        if isinstance(t, BroadcastTransform):
-            r = calculate_broadcast_strides(self.strides, self.backstrides,
-                                            self.res_shape, t.res_shape)
-            return ViewIterator(self.offset, r[0], r[1], t.res_shape)
-        elif isinstance(t, ViewTransform):
-            r = calculate_slice_strides(self.res_shape, self.offset,
-                                        self.strides,
-                                        self.backstrides, t.chunks.l)
-            return ViewIterator(r[1], r[2], r[3], r[0])
-
-    @jit.unroll_safe
-    def next(self, shapelen):
-        shapelen = jit.promote(len(self.res_shape))
-        offset = self.offset
-        indices = [0] * shapelen
-        for i in range(shapelen):
-            indices[i] = self.indices[i]
-        done = False
-        for i in range(shapelen - 1, -1, -1):
-            if indices[i] < self.res_shape[i] - 1:
-                indices[i] += 1
-                offset += self.strides[i]
-                break
-            else:
-                indices[i] = 0
-                offset -= self.backstrides[i]
-        else:
-            done = True
-        res = instantiate(ViewIterator)
-        res.offset = offset
-        res.indices = indices
-        res.strides = self.strides
-        res.backstrides = self.backstrides
-        res.res_shape = self.res_shape
-        res._done = done
-        return res
-
-    @jit.unroll_safe
-    def next_skip_x(self, shapelen, step):
-        shapelen = jit.promote(len(self.res_shape))
-        offset = self.offset
-        indices = [0] * shapelen
-        for i in range(shapelen):
-            indices[i] = self.indices[i]
-        done = False
-        for i in range(shapelen - 1, -1, -1):
-            if indices[i] < self.res_shape[i] - step:
-                indices[i] += step
-                offset += self.strides[i] * step
-                break
-            else:
-                remaining_step = (indices[i] + step) // self.res_shape[i]
-                this_i_step = step - remaining_step * self.res_shape[i]
-                offset += self.strides[i] * this_i_step
-                indices[i] = indices[i] +  this_i_step
-                step = remaining_step
-        else:
-            done = True
-        res = instantiate(ViewIterator)
-        res.offset = offset
-        res.indices = indices
-        res.strides = self.strides
-        res.backstrides = self.backstrides
-        res.res_shape = self.res_shape
-        res._done = done
-        return res
-
-    def apply_transformations(self, arr, transformations):
-        v = BaseIterator.apply_transformations(self, arr, transformations)
-        if len(arr.shape) == 1 and len(v.res_shape) == 1:
-            return OneDimIterator(self.offset, self.strides[0],
-                                  self.res_shape[0])
-        return v
-
-    def done(self):
-        return self._done
-
-class ConstantIterator(BaseIterator):
-    def next(self, shapelen):
-        return self
-
-    def transform(self, arr, t):
-        pass
-
-
-class AxisIterator(BaseIterator):
-    def __init__(self, start, dim, shape, strides, backstrides):
-        self.res_shape = shape[:]
-        if len(shape) == len(strides):
-            # keepdims = True
-            self.strides = strides[:dim] + [0] + strides[dim + 1:]
-            self.backstrides = backstrides[:dim] + [0] + backstrides[dim + 1:]
-        else:
-            self.strides = strides[:dim] + [0] + strides[dim:]
-            self.backstrides = backstrides[:dim] + [0] + backstrides[dim:]
-        self.first_line = True
-        self.indices = [0] * len(shape)
-        self._done = False
-        self.offset = start
-        self.dim = dim
-
-    @jit.unroll_safe
-    def next(self, shapelen):
-        offset = self.offset
-        first_line = self.first_line
-        indices = [0] * shapelen
-        for i in range(shapelen):
-            indices[i] = self.indices[i]
-        done = False
-        for i in range(shapelen - 1, -1, -1):
-            if indices[i] < self.res_shape[i] - 1:
-                if i == self.dim:
-                    first_line = False
-                indices[i] += 1
-                offset += self.strides[i]
-                break
-            else:
-                if i == self.dim:
-                    first_line = True
-                indices[i] = 0
-                offset -= self.backstrides[i]
-        else:
-            done = True
-        res = instantiate(AxisIterator)
-        res.offset = offset
-        res.indices = indices
-        res.strides = self.strides
-        res.backstrides = self.backstrides
-        res.res_shape = self.res_shape
-        res._done = done
-        res.first_line = first_line
-        res.dim = self.dim
-        return res        
-
-    def done(self):
-        return self._done
-
-# ------ other iterators that are not part of the computation frame ----------
-    
-class SkipLastAxisIterator(object):
-    def __init__(self, arr):
-        self.arr = arr
-        self.indices = [0] * (len(arr.shape) - 1)
-        self.done = False
-        self.offset = arr.start
-
-    def next(self):
-        for i in range(len(self.arr.shape) - 2, -1, -1):
-            if self.indices[i] < self.arr.shape[i] - 1:
-                self.indices[i] += 1
-                self.offset += self.arr.strides[i]
-                break
-            else:
-                self.indices[i] = 0
-                self.offset -= self.arr.backstrides[i]
-        else:
-            self.done = True
diff --git a/pypy/module/micronumpy/interp_numarray.py b/pypy/module/micronumpy/interp_numarray.py
--- a/pypy/module/micronumpy/interp_numarray.py
+++ b/pypy/module/micronumpy/interp_numarray.py
@@ -1,88 +1,299 @@
-from pypy.interpreter.baseobjspace import Wrappable
-from pypy.interpreter.error import OperationError, operationerrfmt
+
+from pypy.interpreter.error import operationerrfmt, OperationError
+from pypy.interpreter.typedef import TypeDef, GetSetProperty
 from pypy.interpreter.gateway import interp2app, unwrap_spec
-from pypy.interpreter.typedef import TypeDef, GetSetProperty
-from pypy.module.micronumpy import (interp_ufuncs, interp_dtype, interp_boxes,
-    signature, support, loop)
+from pypy.module.micronumpy.base import W_NDimArray, convert_to_array
+from pypy.module.micronumpy import interp_dtype, interp_ufuncs, interp_boxes
+from pypy.module.micronumpy.strides import find_shape_and_elems,\
+     get_shape_from_iterable, to_coords
+from pypy.module.micronumpy.interp_flatiter import W_FlatIterator
+from pypy.module.micronumpy.interp_support import unwrap_axis_arg
 from pypy.module.micronumpy.appbridge import get_appbridge_cache
-from pypy.module.micronumpy.dot import multidim_dot, match_dot_shapes
-from pypy.module.micronumpy.interp_iter import (ArrayIterator,
-    SkipLastAxisIterator, Chunk, ViewIterator, Chunks, RecordChunk,
-    NewAxisChunk)
-from pypy.module.micronumpy.strides import (shape_agreement,
-    find_shape_and_elems, get_shape_from_iterable, calc_new_strides, to_coords)
+from pypy.module.micronumpy import loop
+from pypy.module.micronumpy.dot import match_dot_shapes
+from pypy.module.micronumpy.interp_arrayops import repeat
+from pypy.tool.sourcetools import func_with_new_name
 from pypy.rlib import jit
 from pypy.rlib.rstring import StringBuilder
-from pypy.rlib.rawstorage import free_raw_storage
-from pypy.rpython.lltypesystem import lltype, rffi
-from pypy.tool.sourcetools import func_with_new_name
-from pypy.module.micronumpy.interp_support import unwrap_axis_arg
 
-count_driver = jit.JitDriver(
-    greens=['shapelen'],
-    virtualizables=['frame'],
-    reds=['s', 'frame', 'iter', 'arr'],
-    name='numpy_count'
-)
-filter_driver = jit.JitDriver(
-    greens=['shapelen', 'sig'],
-    virtualizables=['frame'],
-    reds=['concr', 'argi', 'ri', 'frame', 'v', 'res', 'self'],
-    name='numpy_filter',
-)
-filter_set_driver = jit.JitDriver(
-    greens=['shapelen', 'sig'],
-    virtualizables=['frame'],
-    reds=['idx', 'idxi', 'frame', 'arr'],
-    name='numpy_filterset',
-)
-take_driver = jit.JitDriver(
-    greens=['shapelen', 'sig'],
-    reds=['index_i', 'res_i', 'concr', 'index', 'res'],
-    name='numpy_take',
-)
-flat_get_driver = jit.JitDriver(
-    greens=['shapelen', 'base'],
-    reds=['step', 'ri', 'basei', 'res'],
-    name='numpy_flatget',
-)
-flat_set_driver = jit.JitDriver(
-    greens=['shapelen', 'base'],
-    reds=['step', 'lngth', 'ri', 'arr', 'basei'],
-    name='numpy_flatset',
-)
+def _find_shape(space, w_size):
+    if space.isinstance_w(w_size, space.w_int):
+        return [space.int_w(w_size)]
+    shape = []
+    for w_item in space.fixedview(w_size):
+        shape.append(space.int_w(w_item))
+    return shape
 
-class BaseArray(Wrappable):
-    _attrs_ = ["invalidates", "shape", 'size']
+class __extend__(W_NDimArray):
+    @jit.unroll_safe
+    def descr_get_shape(self, space):
+        shape = self.get_shape()
+        return space.newtuple([space.wrap(i) for i in shape])
 
-    _immutable_fields_ = []
+    def get_shape(self):
+        return self.implementation.get_shape()
 
-    strides = None
-    start = 0
+    def descr_set_shape(self, space, w_new_shape):
+        self.implementation = self.implementation.set_shape(space,
+            get_shape_from_iterable(space, self.get_size(), w_new_shape))
 
-    def __init__(self, shape):
-        self.invalidates = []
-        self.shape = shape
+    def get_dtype(self):
+        return self.implementation.dtype
 
-    def invalidated(self):
-        if self.invalidates:
-            self._invalidated()
+    def get_order(self):
+        return self.implementation.order
 
-    def _invalidated(self):
-        for arr in self.invalidates:
-            arr.force_if_needed()
-        del self.invalidates[:]
+    def descr_get_dtype(self, space):
+        return self.implementation.dtype
 
-    def add_invalidates(self, space, other):
-        if get_numarray_cache(space).enable_invalidation:
-            self.invalidates.append(other)
-        
-    def descr__new__(space, w_subtype, w_size, w_dtype=None):
-        dtype = space.interp_w(interp_dtype.W_Dtype,
-            space.call_function(space.gettypefor(interp_dtype.W_Dtype), w_dtype)
-        )
-        shape = _find_shape(space, w_size)
-        return space.wrap(W_NDimArray(shape[:], dtype=dtype))
+    def descr_get_ndim(self, space):
+        return space.wrap(len(self.get_shape()))
+
+    def descr_get_itemsize(self, space):
+        return space.wrap(self.get_dtype().itemtype.get_element_size())
+
+    def descr_get_nbytes(self, space):
+        return space.wrap(self.get_size() * self.get_dtype().itemtype.get_element_size())
+
+    def descr_fill(self, space, w_value):
+        self.fill(self.get_dtype().coerce(space, w_value))
+
+    def descr_tostring(self, space):
+        return space.wrap(loop.tostring(space, self))
+
+    def getitem_filter(self, space, arr):
+        if arr.get_size() > self.get_size():
+            raise OperationError(space.w_IndexError,
+                                 space.wrap("index out of range for array"))
+        size = loop.count_all_true(arr)
+        res = W_NDimArray.from_shape([size], self.get_dtype())
+        return loop.getitem_filter(res, self, arr)
+
+    def setitem_filter(self, space, idx, val):
+        loop.setitem_filter(self, idx, val)
+
+    def descr_getitem(self, space, w_idx):
+        if (isinstance(w_idx, W_NDimArray) and w_idx.get_shape() == self.get_shape() and
+            w_idx.get_dtype().is_bool_type()):
+            return self.getitem_filter(space, w_idx)
+        try:
+            return self.implementation.descr_getitem(space, w_idx)
+        except OperationError:
+            raise OperationError(space.w_IndexError, space.wrap("wrong index"))
+
+    def descr_setitem(self, space, w_idx, w_value):
+        if (isinstance(w_idx, W_NDimArray) and w_idx.get_shape() == self.get_shape() and
+            w_idx.get_dtype().is_bool_type()):
+            return self.setitem_filter(space, w_idx,
+                                       convert_to_array(space, w_value))
+        self.implementation.descr_setitem(space, w_idx, w_value)
+
+    def descr_len(self, space):
+        shape = self.get_shape()
+        if len(shape):
+            return space.wrap(shape[0])
+        raise OperationError(space.w_TypeError, space.wrap(
+            "len() of unsized object"))
+
+    def descr_repr(self, space):
+        cache = get_appbridge_cache(space)
+        if cache.w_array_repr is None:
+            return space.wrap(self.dump_data())
+        return space.call_function(cache.w_array_repr, self)
+
+    def descr_str(self, space):
+        cache = get_appbridge_cache(space)
+        if cache.w_array_str is None:
+            return space.wrap(self.dump_data())
+        return space.call_function(cache.w_array_str, self)
+
+    def dump_data(self):
+        i = self.create_iter(self.get_shape())
+        first = True
+        dtype = self.get_dtype()
+        s = StringBuilder()
+        s.append('array([')
+        while not i.done():
+            if first:
+                first = False
+            else:
+                s.append(', ')
+            s.append(dtype.itemtype.str_format(i.getitem()))
+            i.next()
+        s.append('])')
+        return s.build()
+
+    def create_iter(self, shape=None):
+        if shape is None:
+            shape = self.get_shape()
+        return self.implementation.create_iter(shape)
+
+    def create_axis_iter(self, shape, dim):
+        return self.implementation.create_axis_iter(shape, dim)
+
+    def create_dot_iter(self, shape, skip):
+        return self.implementation.create_dot_iter(shape, skip)
+
+    def is_scalar(self):
+        return self.implementation.is_scalar()
+
+    def set_scalar_value(self, w_val):
+        self.implementation.set_scalar_value(w_val)
+
+    def fill(self, box):
+        self.implementation.fill(box)
+
+    def descr_get_size(self, space):
+        return space.wrap(self.get_size())
+
+    def get_size(self):
+        return self.implementation.get_size()
+
+    def get_scalar_value(self):
+        return self.implementation.get_scalar_value()
+
+    def descr_copy(self, space):
+        return W_NDimArray(self.implementation.copy())
+
+    def descr_reshape(self, space, args_w):
+        """reshape(...)
+        a.reshape(shape)
+
+        Returns an array containing the same data with a new shape.
+
+        Refer to `numpypy.reshape` for full documentation.
+
+        See Also
+        --------
+        numpypy.reshape : equivalent function
+        """
+        if len(args_w) == 1:
+            w_shape = args_w[0]
+        else:
+            w_shape = space.newtuple(args_w)
+        new_shape = get_shape_from_iterable(space, self.get_size(), w_shape)
+        new_impl = self.implementation.reshape(space, new_shape)
+        if new_impl is not None:
+            return W_NDimArray(new_impl)
+        # Create copy with contiguous data
+        arr = self.descr_copy(space)
+        if arr.get_size() > 0:
+            arr.implementation = arr.implementation.reshape(space, new_shape)
+            assert arr.implementation
+        else:
+            arr.implementation.shape = new_shape
+        return arr
+
+    def descr_get_transpose(self, space):
+        return W_NDimArray(self.implementation.transpose())
+
+    @unwrap_spec(axis1=int, axis2=int)
+    def descr_swapaxes(self, space, axis1, axis2):
+        """a.swapaxes(axis1, axis2)
+    
+        Return a view of the array with `axis1` and `axis2` interchanged.
+    
+        Refer to `numpy.swapaxes` for full documentation.
+    
+        See Also
+        --------
+        numpy.swapaxes : equivalent function
+        """
+        if self.is_scalar():
+            return self
+        return self.implementation.swapaxes(axis1, axis2)
+
+    def descr_tolist(self, space):
+        if len(self.get_shape()) == 0:
+            return self.get_scalar_value().item(space)
+        l_w = []
+        for i in range(self.get_shape()[0]):
+            l_w.append(space.call_method(self.descr_getitem(space,
+                                         space.wrap(i)), "tolist"))
+        return space.newlist(l_w)
+
+    def descr_ravel(self, space, w_order=None):
+        if w_order is None or space.is_w(w_order, space.w_None):
+            order = 'C'
+        else:
+            order = space.str_w(w_order)
+        if order != 'C':
+            raise OperationError(space.w_NotImplementedError, space.wrap(
+                "order not implemented"))
+        return self.descr_reshape(space, [space.wrap(-1)])
+
+    def descr_take(self, space, w_obj, w_axis=None, w_out=None):
+        # if w_axis is None and w_out is Nont this is an equivalent to
+        # fancy indexing
+        raise Exception("unsupported for now")
+        if not space.is_w(w_axis, space.w_None):
+            raise OperationError(space.w_NotImplementedError,
+                                 space.wrap("axis unsupported for take"))
+        if not space.is_w(w_out, space.w_None):
+            raise OperationError(space.w_NotImplementedError,
+                                 space.wrap("out unsupported for take"))
+        return self.getitem_int(space, convert_to_array(space, w_obj))
+
+    def descr_compress(self, space, w_obj, w_axis=None):
+        index = convert_to_array(space, w_obj)
+        return self.getitem_filter(space, index)
+
+    def descr_flatten(self, space, w_order=None):
+        if self.is_scalar():
+            # scalars have no storage
+            return self.descr_reshape(space, [space.wrap(1)])
+        w_res = self.descr_ravel(space, w_order)
+        if w_res.implementation.storage == self.implementation.storage:
+            return w_res.descr_copy(space)
+        return w_res
+
+    @unwrap_spec(repeats=int)
+    def descr_repeat(self, space, repeats, w_axis=None):
+        return repeat(space, self, repeats, w_axis)
+
+    def descr_get_flatiter(self, space):
+        return space.wrap(W_FlatIterator(self))
+
+    def to_coords(self, space, w_index):
+        coords, _, _ = to_coords(space, self.get_shape(),
+                                 self.get_size(), self.get_order(),
+                                 w_index)
+        return coords
+
+    def descr_item(self, space, w_arg=None):
+        if space.is_w(w_arg, space.w_None):
+            if self.is_scalar():
+                return self.get_scalar_value().item(space)
+            if self.get_size() == 1:
+                w_obj = self.descr_getitem(space,
+                                           space.newtuple([space.wrap(0) for i
+                                      in range(len(self.get_shape()))]))
+                assert isinstance(w_obj, interp_boxes.W_GenericBox)
+                return w_obj.item(space)
+            raise OperationError(space.w_IndexError,
+                                 space.wrap("index out of bounds"))
+        if space.isinstance_w(w_arg, space.w_int):
+            if self.is_scalar():
+                raise OperationError(space.w_IndexError,
+                                     space.wrap("index out of bounds"))
+            i = self.to_coords(space, w_arg)
+            item = self.descr_getitem(space, space.newtuple([space.wrap(x)
+                                             for x in i]))
+            assert isinstance(item, interp_boxes.W_GenericBox)
+            return item.item(space)
+        raise OperationError(space.w_NotImplementedError, space.wrap(
+            "non-int arg not supported"))
+
+    def descr_array_iface(self, space):
+        addr = self.implementation.get_storage_as_int(space)
+        # will explode if it can't
+        w_d = space.newdict()
+        space.setitem_str(w_d, 'data', space.newtuple([space.wrap(addr),
+                                                       space.w_False]))
+        return w_d
+
+
+    # --------------------- operations ----------------------------
 
     def _unaryop_impl(ufunc_name):
         def impl(self, space, w_out=None):
@@ -95,6 +306,13 @@
     descr_abs = _unaryop_impl("absolute")
     descr_invert = _unaryop_impl("invert")
 
+    def descr_nonzero(self, space):
+        if self.get_size() > 1:
+            raise OperationError(space.w_ValueError, space.wrap(
+                "The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()"))
+        iter = self.create_iter(self.get_shape())
+        return space.wrap(space.is_true(iter.getitem()))
+
     def _binop_impl(ufunc_name):
         def impl(self, space, w_other, w_out=None):
             return getattr(interp_ufuncs.get(space), ufunc_name).call(space,
@@ -115,6 +333,11 @@
     descr_or = _binop_impl("bitwise_or")
     descr_xor = _binop_impl("bitwise_xor")
 
+    def descr_divmod(self, space, w_other):
+        w_quotient = self.descr_div(space, w_other)
+        w_remainder = self.descr_mod(space, w_other)
+        return space.newtuple([w_quotient, w_remainder])
+
     descr_eq = _binop_impl("equal")
     descr_ne = _binop_impl("not_equal")
     descr_lt = _binop_impl("less")
@@ -122,17 +345,11 @@
     descr_gt = _binop_impl("greater")
     descr_ge = _binop_impl("greater_equal")
 
-    def descr_divmod(self, space, w_other):
-        w_quotient = self.descr_div(space, w_other)
-        w_remainder = self.descr_mod(space, w_other)
-        return space.newtuple([w_quotient, w_remainder])
-
     def _binop_right_impl(ufunc_name):
         def impl(self, space, w_other, w_out=None):
-            w_other = scalar_w(space,
-                interp_ufuncs.find_dtype_for_scalar(space, w_other, self.find_dtype()),
-                w_other
-            )
+            dtype = interp_ufuncs.find_dtype_for_scalar(space, w_other,
+                                                        self.get_dtype())
+            w_other = W_NDimArray.new_scalar(space, dtype, w_other)
             return getattr(interp_ufuncs.get(space), ufunc_name).call(space, [w_other, self, w_out])
         return func_with_new_name(impl, "binop_right_%s_impl" % ufunc_name)
 
@@ -155,18 +372,49 @@
         w_remainder = self.descr_rmod(space, w_other)
         return space.newtuple([w_quotient, w_remainder])
 
+    def descr_dot(self, space, w_other):
+        other = convert_to_array(space, w_other)
+        if other.is_scalar():
+            #Note: w_out is not modified, this is numpy compliant.
+            return self.descr_mul(space, other)
+        elif len(self.get_shape()) < 2 and len(other.get_shape()) < 2:
+            w_res = self.descr_mul(space, other)
+            assert isinstance(w_res, W_NDimArray)
+            return w_res.descr_sum(space, space.wrap(-1))
+        dtype = interp_ufuncs.find_binop_result_dtype(space,
+                                     self.get_dtype(), other.get_dtype())
+        if self.get_size() < 1 and other.get_size() < 1:
+            # numpy compatability
+            return W_NDimArray.new_scalar(space, dtype, space.wrap(0))
+        # Do the dims match?
+        out_shape, other_critical_dim = match_dot_shapes(space, self, other)
+        result = W_NDimArray.from_shape(out_shape, dtype)
+        # This is the place to add fpypy and blas
+        return loop.multidim_dot(space, self, other,  result, dtype,
+                                 other_critical_dim)
+
+    def descr_var(self, space, w_axis=None):
+        return get_appbridge_cache(space).call_method(space, '_var', self,
+                                                      w_axis)
+
+    def descr_std(self, space, w_axis=None):
+        return get_appbridge_cache(space).call_method(space, '_std', self,
+                                                      w_axis)
+
+    # ----------------------- reduce -------------------------------
+
     def _reduce_ufunc_impl(ufunc_name, promote_to_largest=False):
-        def impl(self, space, w_axis=None, w_out=None):
+        def impl(self, space, w_axis=None, w_out=None, w_dtype=None):
             if space.is_w(w_out, space.w_None) or not w_out:
                 out = None
-            elif not isinstance(w_out, BaseArray):
+            elif not isinstance(w_out, W_NDimArray):
                 raise OperationError(space.w_TypeError, space.wrap( 
                         'output must be an array'))
             else:
                 out = w_out
             return getattr(interp_ufuncs.get(space), ufunc_name).reduce(space,
                                         self, True, promote_to_largest, w_axis,
-                                                                   False, out)
+                                                         False, out, w_dtype)
         return func_with_new_name(impl, "reduce_%s_impl" % ufunc_name)
 
     descr_sum = _reduce_ufunc_impl("add")
@@ -177,1088 +425,162 @@
     descr_all = _reduce_ufunc_impl('logical_and')
     descr_any = _reduce_ufunc_impl('logical_or')
 
+    def descr_mean(self, space, w_axis=None, w_out=None):
+        if space.is_w(w_axis, space.w_None):
+            w_denom = space.wrap(self.get_size())
+        else:
+            axis = unwrap_axis_arg(space, len(self.get_shape()), w_axis)
+            w_denom = space.wrap(self.get_shape()[axis])
+        return space.div(self.descr_sum_promote(space, w_axis, w_out), w_denom)
+
     def _reduce_argmax_argmin_impl(op_name):
-        reduce_driver = jit.JitDriver(
-            greens=['shapelen', 'sig'],
-            reds=['result', 'idx', 'frame', 'self', 'cur_best', 'dtype'],
-            get_printable_location=signature.new_printable_location(op_name),
-            name='numpy_' + op_name,
-        )
-        def loop(self):
-            sig = self.find_sig()
-            frame = sig.create_frame(self)
-            cur_best = sig.eval(frame, self)
-            shapelen = len(self.shape)
-            frame.next(shapelen)
-            dtype = self.find_dtype()
-            result = 0
-            idx = 1
-            while not frame.done():
-                reduce_driver.jit_merge_point(sig=sig,
-                                              shapelen=shapelen,
-                                              self=self, dtype=dtype,
-                                              frame=frame, result=result,
-                                              idx=idx,
-                                              cur_best=cur_best)
-                new_best = getattr(dtype.itemtype, op_name)(cur_best, sig.eval(frame, self))
-                if dtype.itemtype.ne(new_best, cur_best):
-                    result = idx
-                    cur_best = new_best
-                frame.next(shapelen)
-                idx += 1
-            return result
-
         def impl(self, space):
-            if self.size == 0:
+            if self.get_size() == 0:
                 raise OperationError(space.w_ValueError,
                     space.wrap("Can't call %s on zero-size arrays" % op_name))
-            return space.wrap(loop(self))
+            return space.wrap(loop.argmin_argmax(op_name, self))
         return func_with_new_name(impl, "reduce_arg%s_impl" % op_name)
 
     descr_argmax = _reduce_argmax_argmin_impl("max")
     descr_argmin = _reduce_argmax_argmin_impl("min")
 
-    def descr_dot(self, space, w_other):
-        other = convert_to_array(space, w_other)
-        if isinstance(other, Scalar):
-            #Note: w_out is not modified, this is numpy compliant.
-            return self.descr_mul(space, other)
-        elif len(self.shape) < 2 and len(other.shape) < 2:
-            w_res = self.descr_mul(space, other)
-            assert isinstance(w_res, BaseArray)
-            return w_res.descr_sum(space, space.wrap(-1))
-        dtype = interp_ufuncs.find_binop_result_dtype(space,
-                                     self.find_dtype(), other.find_dtype())
-        if self.size < 1 and other.size < 1:
-            # numpy compatability
-            return scalar_w(space, dtype, space.wrap(0))
-        # Do the dims match?
-        out_shape, other_critical_dim = match_dot_shapes(space, self, other)
-        result = W_NDimArray(out_shape, dtype)
-        # This is the place to add fpypy and blas
-        return multidim_dot(space, self.get_concrete(),
-                            other.get_concrete(), result, dtype,
-                            other_critical_dim)
 
-    def get_concrete(self):
-        raise NotImplementedError
+ at unwrap_spec(offset=int)
+def descr_new_array(space, w_subtype, w_shape, w_dtype=None, w_buffer=None,
+                    offset=0, w_strides=None, w_order=None):
+    if (offset != 0 or not space.is_w(w_strides, space.w_None) or
+        not space.is_w(w_order, space.w_None) or
+        not space.is_w(w_buffer, space.w_None)):
+        raise OperationError(space.w_NotImplementedError,
+                             space.wrap("unsupported param"))
+    dtype = space.interp_w(interp_dtype.W_Dtype,
+          space.call_function(space.gettypefor(interp_dtype.W_Dtype), w_dtype))
+    shape = _find_shape(space, w_shape)
+    if not shape:
+        return W_NDimArray.new_scalar(space, dtype)
+    return W_NDimArray.from_shape(shape, dtype)
 
-    def descr_get_dtype(self, space):
-        return space.wrap(self.find_dtype())
+W_NDimArray.typedef = TypeDef(
+    "ndarray",
+    __new__ = interp2app(descr_new_array),
 
-    def descr_get_ndim(self, space):
-        return space.wrap(len(self.shape))
+    __len__ = interp2app(W_NDimArray.descr_len),
+    __getitem__ = interp2app(W_NDimArray.descr_getitem),
+    __setitem__ = interp2app(W_NDimArray.descr_setitem),
 
-    def descr_get_itemsize(self, space):
-        return space.wrap(self.find_dtype().itemtype.get_element_size())
+    __repr__ = interp2app(W_NDimArray.descr_repr),
+    __str__ = interp2app(W_NDimArray.descr_str),
 
-    def descr_get_nbytes(self, space):
-        return space.wrap(self.size)
+    __pos__ = interp2app(W_NDimArray.descr_pos),
+    __neg__ = interp2app(W_NDimArray.descr_neg),
+    __abs__ = interp2app(W_NDimArray.descr_abs),
+    __invert__ = interp2app(W_NDimArray.descr_invert),
+    __nonzero__ = interp2app(W_NDimArray.descr_nonzero),
 
-    @jit.unroll_safe
-    def descr_get_shape(self, space):
-        return space.newtuple([space.wrap(i) for i in self.shape])
+    __add__ = interp2app(W_NDimArray.descr_add),
+    __sub__ = interp2app(W_NDimArray.descr_sub),
+    __mul__ = interp2app(W_NDimArray.descr_mul),
+    __div__ = interp2app(W_NDimArray.descr_div),
+    __truediv__ = interp2app(W_NDimArray.descr_truediv),
+    __floordiv__ = interp2app(W_NDimArray.descr_floordiv),
+    __mod__ = interp2app(W_NDimArray.descr_mod),
+    __divmod__ = interp2app(W_NDimArray.descr_divmod),
+    __pow__ = interp2app(W_NDimArray.descr_pow),
+    __lshift__ = interp2app(W_NDimArray.descr_lshift),
+    __rshift__ = interp2app(W_NDimArray.descr_rshift),
+    __and__ = interp2app(W_NDimArray.descr_and),
+    __or__ = interp2app(W_NDimArray.descr_or),
+    __xor__ = interp2app(W_NDimArray.descr_xor),
 
-    def descr_set_shape(self, space, w_iterable):
-        new_shape = get_shape_from_iterable(space,
-                            support.product(self.shape), w_iterable)
-        if isinstance(self, Scalar):
-            return
-        self.get_concrete().setshape(space, new_shape)
+    __radd__ = interp2app(W_NDimArray.descr_radd),
+    __rsub__ = interp2app(W_NDimArray.descr_rsub),
+    __rmul__ = interp2app(W_NDimArray.descr_rmul),
+    __rdiv__ = interp2app(W_NDimArray.descr_rdiv),
+    __rtruediv__ = interp2app(W_NDimArray.descr_rtruediv),
+    __rfloordiv__ = interp2app(W_NDimArray.descr_rfloordiv),
+    __rmod__ = interp2app(W_NDimArray.descr_rmod),
+    __rdivmod__ = interp2app(W_NDimArray.descr_rdivmod),
+    __rpow__ = interp2app(W_NDimArray.descr_rpow),
+    __rlshift__ = interp2app(W_NDimArray.descr_rlshift),
+    __rrshift__ = interp2app(W_NDimArray.descr_rrshift),
+    __rand__ = interp2app(W_NDimArray.descr_rand),
+    __ror__ = interp2app(W_NDimArray.descr_ror),
+    __rxor__ = interp2app(W_NDimArray.descr_rxor),
 
-    def descr_get_size(self, space):
-        return space.wrap(self.get_size())
+    __eq__ = interp2app(W_NDimArray.descr_eq),
+    __ne__ = interp2app(W_NDimArray.descr_ne),
+    __lt__ = interp2app(W_NDimArray.descr_lt),
+    __le__ = interp2app(W_NDimArray.descr_le),
+    __gt__ = interp2app(W_NDimArray.descr_gt),
+    __ge__ = interp2app(W_NDimArray.descr_ge),
 
-    def get_size(self):
-        return self.size // self.find_dtype().get_size()
+    dtype = GetSetProperty(W_NDimArray.descr_get_dtype),
+    shape = GetSetProperty(W_NDimArray.descr_get_shape,
+                           W_NDimArray.descr_set_shape),
+    ndim = GetSetProperty(W_NDimArray.descr_get_ndim),
+    size = GetSetProperty(W_NDimArray.descr_get_size),
+    itemsize = GetSetProperty(W_NDimArray.descr_get_itemsize),
+    nbytes = GetSetProperty(W_NDimArray.descr_get_nbytes),
 
-    def descr_copy(self, space):
-        return self.copy(space)
+    fill = interp2app(W_NDimArray.descr_fill),
+    tostring = interp2app(W_NDimArray.descr_tostring),
 
-    def descr_flatten(self, space, w_order=None):
-        if isinstance(self, Scalar):
-            # scalars have no storage
-            return self.descr_reshape(space, [space.wrap(1)])
-        concr = self.get_concrete()
-        w_res = concr.descr_ravel(space, w_order)
-        if w_res.storage == concr.storage:
-            return w_res.copy(space)
-        return w_res
+    mean = interp2app(W_NDimArray.descr_mean),
+    sum = interp2app(W_NDimArray.descr_sum),
+    prod = interp2app(W_NDimArray.descr_prod),
+    max = interp2app(W_NDimArray.descr_max),
+    min = interp2app(W_NDimArray.descr_min),
+    argmax = interp2app(W_NDimArray.descr_argmax),
+    argmin = interp2app(W_NDimArray.descr_argmin),
+    all = interp2app(W_NDimArray.descr_all),
+    any = interp2app(W_NDimArray.descr_any),
+    dot = interp2app(W_NDimArray.descr_dot),
+    var = interp2app(W_NDimArray.descr_var),
+    std = interp2app(W_NDimArray.descr_std),
 
-    def copy(self, space):
-        return self.get_concrete().copy(space)
+    copy = interp2app(W_NDimArray.descr_copy),
+    reshape = interp2app(W_NDimArray.descr_reshape),
+    T = GetSetProperty(W_NDimArray.descr_get_transpose),
+    transpose = interp2app(W_NDimArray.descr_get_transpose),
+    tolist = interp2app(W_NDimArray.descr_tolist),
+    flatten = interp2app(W_NDimArray.descr_flatten),
+    ravel = interp2app(W_NDimArray.descr_ravel),
+    take = interp2app(W_NDimArray.descr_take),
+    compress = interp2app(W_NDimArray.descr_compress),
+    repeat = interp2app(W_NDimArray.descr_repeat),
+    swapaxes = interp2app(W_NDimArray.descr_swapaxes),
+    flat = GetSetProperty(W_NDimArray.descr_get_flatiter),
+    item = interp2app(W_NDimArray.descr_item),
 
-    def empty_copy(self, space, dtype):
-        shape = self.shape
-        return W_NDimArray(shape[:], dtype, 'C')
+    __array_interface__ = GetSetProperty(W_NDimArray.descr_array_iface),
+)
 
-    def descr_len(self, space):
-        if len(self.shape):
-            return space.wrap(self.shape[0])
-        raise OperationError(space.w_TypeError, space.wrap(
-            "len() of unsized object"))
-
-    def descr_repr(self, space):
-        cache = get_appbridge_cache(space)
-        if cache.w_array_repr is None:
-            return space.wrap(self.dump_data())
-        return space.call_function(cache.w_array_repr, self)
-
-    def dump_data(self):
-        concr = self.get_concrete()
-        i = concr.create_iter()
-        first = True
-        s = StringBuilder()
-        s.append('array([')
-        while not i.done():
-            if first:
-                first = False
-            else:
-                s.append(', ')
-            s.append(concr.dtype.itemtype.str_format(concr.getitem(i.offset)))
-            i = i.next(len(concr.shape))
-        s.append('])')
-        return s.build()
-
-    def descr_str(self, space):
-        cache = get_appbridge_cache(space)
-        if cache.w_array_str is None:
-            return space.wrap(self.dump_data())
-        return space.call_function(cache.w_array_str, self)
-
-    @jit.unroll_safe
-    def _single_item_result(self, space, w_idx):
-        """ The result of getitem/setitem is a single item if w_idx
-        is a list of scalars that match the size of shape
-        """
-        if space.isinstance_w(w_idx, space.w_str):
-            return False
-        shape_len = len(self.shape)
-        if space.isinstance_w(w_idx, space.w_tuple):
-            for w_item in space.fixedview(w_idx):
-                if (space.isinstance_w(w_item, space.w_slice) or
-                    space.is_w(w_item, space.w_None)):
-                    return False
-        elif space.is_w(w_idx, space.w_None):
-            return False
-        if shape_len == 0:
-            raise OperationError(space.w_IndexError, space.wrap(
-                "0-d arrays can't be indexed"))
-        if shape_len == 1:
-            if space.isinstance_w(w_idx, space.w_int):
-                return True
-
-            try:
-                value = space.int_w(space.index(w_idx))
-                return True
-            except OperationError:
-                pass
-
-            try:
-                value = space.int_w(w_idx)
-                return True
-            except OperationError:
-                pass
-
-            if space.isinstance_w(w_idx, space.w_slice):
-                return False
-        elif (space.isinstance_w(w_idx, space.w_slice) or
-              space.isinstance_w(w_idx, space.w_int)):
-            return False
-
-        try:
-            lgt = space.len_w(w_idx)
-        except OperationError:
-            raise OperationError(space.w_IndexError,
-                                 space.wrap("index must be either an int or a sequence."))
-
-        if lgt > shape_len:
-            raise OperationError(space.w_IndexError,
-                                 space.wrap("invalid index"))
-        return lgt == shape_len
-
-    @jit.unroll_safe
-    def _prepare_slice_args(self, space, w_idx):
-        if space.isinstance_w(w_idx, space.w_str):
-            idx = space.str_w(w_idx)
-            dtype = self.find_dtype()
-            if not dtype.is_record_type() or idx not in dtype.fields:
-                raise OperationError(space.w_ValueError, space.wrap(
-                    "field named %s not defined" % idx))
-            return RecordChunk(idx)
-        if (space.isinstance_w(w_idx, space.w_int) or
-            space.isinstance_w(w_idx, space.w_slice)):
-            return Chunks([Chunk(*space.decode_index4(w_idx, self.shape[0]))])
-        elif space.is_w(w_idx, space.w_None):
-            return Chunks([NewAxisChunk()])
-        result = []
-        i = 0
-        for w_item in space.fixedview(w_idx):
-            if space.is_w(w_item, space.w_None):
-                result.append(NewAxisChunk())
-            else:
-                result.append(Chunk(*space.decode_index4(w_item,
-                                                         self.shape[i])))
-                i += 1
-        return Chunks(result)
-
-    def descr_count_nonzero(self, space):
-        concr = self.get_concrete()
-        res = concr.count_all_true()
-        return space.wrap(res)
-
-    def count_all_true(self):
-        sig = self.find_sig()
-        frame = sig.create_frame(self)
-        shapelen = len(self.shape)
-        s = 0
-        iter = None
-        while not frame.done():
-            count_driver.jit_merge_point(arr=self, frame=frame, iter=iter, s=s,
-                                         shapelen=shapelen)
-            iter = frame.get_final_iter()
-            s += self.dtype.getitem_bool(self, iter.offset)
-            frame.next(shapelen)
-        return s
-
-    def getitem_filter(self, space, arr):
-        concr = arr.get_concrete()
-        if concr.get_size() > self.get_size():
-            raise OperationError(space.w_IndexError,
-                                 space.wrap("index out of range for array"))
-        size = concr.count_all_true()
-        res = W_NDimArray([size], self.find_dtype())
-        ri = res.create_iter()
-        shapelen = len(self.shape)
-        argi = concr.create_iter()
-        sig = self.find_sig()
-        frame = sig.create_frame(self)
-        v = None
-        while not ri.done():
-            filter_driver.jit_merge_point(concr=concr, argi=argi, ri=ri,
-                                          frame=frame, v=v, res=res, sig=sig,
-                                          shapelen=shapelen, self=self)
-            if concr.dtype.getitem_bool(concr, argi.offset):
-                v = sig.eval(frame, self)
-                res.setitem(ri.offset, v)
-                ri = ri.next(1)
-            else:
-                ri = ri.next_no_increase(1)
-            argi = argi.next(shapelen)
-            frame.next(shapelen)
-        return res
-
-    def descr_getitem(self, space, w_idx):
-        if (isinstance(w_idx, BaseArray) and w_idx.shape == self.shape and
-            w_idx.find_dtype().is_bool_type()):
-            return self.getitem_filter(space, w_idx)
-        if self._single_item_result(space, w_idx):
-            concrete = self.get_concrete()
-            item = concrete._index_of_single_item(space, w_idx)
-            return concrete.getitem(item)
-        chunks = self._prepare_slice_args(space, w_idx)
-        return chunks.apply(self)
-
-    def setitem_filter(self, space, idx, val):
-        size = idx.count_all_true()
-        arr = SliceArray([size], self.dtype, self, val)
-        sig = arr.find_sig()
-        shapelen = len(self.shape)
-        frame = sig.create_frame(arr)
-        idxi = idx.create_iter()
-        while not frame.done():
-            filter_set_driver.jit_merge_point(idx=idx, idxi=idxi, sig=sig,
-                                              frame=frame, arr=arr,
-                                              shapelen=shapelen)
-            if idx.dtype.getitem_bool(idx, idxi.offset):
-                sig.eval(frame, arr)
-                frame.next_from_second(1)
-            frame.next_first(shapelen)
-            idxi = idxi.next(shapelen)
-
-    def descr_setitem(self, space, w_idx, w_value):
-        self.invalidated()
-        if (isinstance(w_idx, BaseArray) and w_idx.shape == self.shape and
-            w_idx.find_dtype().is_bool_type()):
-            return self.get_concrete().setitem_filter(space,
-                                                      w_idx.get_concrete(),
-                                             convert_to_array(space, w_value))
-        if self._single_item_result(space, w_idx):
-            concrete = self.get_concrete()
-            item = concrete._index_of_single_item(space, w_idx)
-            dtype = concrete.find_dtype()
-            concrete.setitem(item, dtype.coerce(space, w_value))
-            return
-        if not isinstance(w_value, BaseArray):
-            w_value = convert_to_array(space, w_value)
-        chunks = self._prepare_slice_args(space, w_idx)
-        view = chunks.apply(self).get_concrete()
-        view.setslice(space, w_value)
-
-    def descr_reshape(self, space, args_w):
-        """reshape(...)
-        a.reshape(shape)
-
-        Returns an array containing the same data with a new shape.
-
-        Refer to `numpypy.reshape` for full documentation.
-
-        See Also
-        --------
-        numpypy.reshape : equivalent function
-        """
-        if len(args_w) == 1:
-            w_shape = args_w[0]
-        else:
-            w_shape = space.newtuple(args_w)
-        new_shape = get_shape_from_iterable(space, support.product(self.shape),
-                                            w_shape)
-        return self.reshape(space, new_shape)
-
-    def reshape(self, space, new_shape):
-        concrete = self.get_concrete()
-        # Since we got to here, prod(new_shape) == self.size
-        new_strides = None
-        if self.size > 0:
-            new_strides = calc_new_strides(new_shape, concrete.shape,
-                                     concrete.strides, concrete.order)
-        if new_strides:
-            # We can create a view, strides somehow match up.
-            ndims = len(new_shape)
-            new_backstrides = [0] * ndims
-            for nd in range(ndims):
-                new_backstrides[nd] = (new_shape[nd] - 1) * new_strides[nd]
-            arr = W_NDimSlice(concrete.start, new_strides, new_backstrides,
-                              new_shape, concrete)
-        else:
-            # Create copy with contiguous data
-            arr = concrete.copy(space)
-            arr.setshape(space, new_shape)
-        return arr
-       
-    @unwrap_spec(axis1=int, axis2=int)
-    def descr_swapaxes(self, space, axis1, axis2):
-        """a.swapaxes(axis1, axis2)
-    
-        Return a view of the array with `axis1` and `axis2` interchanged.
-    
-        Refer to `numpy.swapaxes` for full documentation.
-    
-        See Also
-        --------
-        numpy.swapaxes : equivalent function
-        """
-        concrete = self.get_concrete()
-        shape = concrete.shape[:]
-        strides = concrete.strides[:]
-        backstrides = concrete.backstrides[:]
-        shape[axis1], shape[axis2] = shape[axis2], shape[axis1]   
-        strides[axis1], strides[axis2] = strides[axis2], strides[axis1]
-        backstrides[axis1], backstrides[axis2] = backstrides[axis2], backstrides[axis1] 
-        arr = W_NDimSlice(concrete.start, strides, 
-                           backstrides, shape, concrete)
-        return space.wrap(arr)   
-                                      
-    def descr_tolist(self, space):
-        if len(self.shape) == 0:
-            assert isinstance(self, Scalar)
-            return self.value.item(space)
-        w_result = space.newlist([])
-        for i in range(self.shape[0]):
-            space.call_method(w_result, "append",
-                space.call_method(self.descr_getitem(space, space.wrap(i)), "tolist")
-            )
-        return w_result
-
-    def descr_mean(self, space, w_axis=None, w_out=None):
-        if space.is_w(w_axis, space.w_None):
-            w_denom = space.wrap(support.product(self.shape))
-        else:
-            axis = unwrap_axis_arg(space, len(self.shape), w_axis)
-            w_denom = space.wrap(self.shape[axis])
-        return space.div(self.descr_sum_promote(space, w_axis, w_out), w_denom)
-
-    def descr_var(self, space, w_axis=None):
-        return get_appbridge_cache(space).call_method(space, '_var', self,
-                                                      w_axis)
-
-    def descr_std(self, space, w_axis=None):
-        return get_appbridge_cache(space).call_method(space, '_std', self,
-                                                      w_axis)
-
-    def descr_fill(self, space, w_value):
-        concr = self.get_concrete_or_scalar()
-        concr.fill(space, w_value)
-
-    def descr_nonzero(self, space):
-        if self.get_size() > 1:
-            raise OperationError(space.w_ValueError, space.wrap(
-                "The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()"))
-        concr = self.get_concrete_or_scalar()
-        sig = concr.find_sig()
-        frame = sig.create_frame(self)
-        return space.wrap(space.is_true(
-            sig.eval(frame, concr)))
-
-    def get_concrete_or_scalar(self):
-        return self.get_concrete()
-
-    def descr_get_transpose(self, space):
-        concrete = self.get_concrete()
-        if len(concrete.shape) < 2:
-            return space.wrap(self)
-        strides = []
-        backstrides = []
-        shape = []
-        for i in range(len(concrete.shape) - 1, -1, -1):
-            strides.append(concrete.strides[i])
-            backstrides.append(concrete.backstrides[i])
-            shape.append(concrete.shape[i])
-        return space.wrap(W_NDimSlice(concrete.start, strides,
-                                      backstrides, shape, concrete))
-
-    def descr_ravel(self, space, w_order=None):
-        if w_order is None or space.is_w(w_order, space.w_None):
-            order = 'C'
-        else:
-            order = space.str_w(w_order)
-        if order != 'C':
-            raise OperationError(space.w_NotImplementedError, space.wrap(
-                "order not implemented"))
-        return self.descr_reshape(space, [space.wrap(-1)])
-
-    def descr_get_flatiter(self, space):
-        return space.wrap(W_FlatIterator(self))
-
-    def getitem(self, item):
-        raise NotImplementedError
-
-    def find_sig(self, res_shape=None, arr=None):
-        """ find a correct signature for the array
-        """
-        res_shape = res_shape or self.shape
-        arr = arr or self
-        return signature.find_sig(self.create_sig(), arr)
-
-    def descr_array_iface(self, space):
-        if not self.shape:
-            raise OperationError(space.w_TypeError,
-                space.wrap("can't get the array data of a 0-d array for now")
-            )
-        concrete = self.get_concrete()
-        storage = concrete.storage
-        addr = rffi.cast(lltype.Signed, storage)
-        w_d = space.newdict()
-        space.setitem_str(w_d, 'data', space.newtuple([space.wrap(addr),
-                                                       space.w_False]))
-        return w_d
-
-    def supports_fast_slicing(self):
-        return False
-
-    def descr_compress(self, space, w_obj, w_axis=None):
-        index = convert_to_array(space, w_obj)
-        return self.getitem_filter(space, index)
-
-    def descr_take(self, space, w_obj, w_axis=None):
-        index = convert_to_array(space, w_obj).get_concrete()
-        concr = self.get_concrete()
-        if space.is_w(w_axis, space.w_None):
-            concr = concr.descr_ravel(space)
-        else:
-            raise OperationError(space.w_NotImplementedError,
-                                 space.wrap("axis unsupported for take"))
-        index_i = index.create_iter()
-        res_shape = index.shape
-        res = W_NDimArray(res_shape[:], concr.dtype, concr.order)
-        res_i = res.create_iter()
-        shapelen = len(index.shape)
-        sig = concr.find_sig()
-        while not index_i.done():
-            take_driver.jit_merge_point(index_i=index_i, index=index,
-                                        res_i=res_i, concr=concr,
-                                        res=res,
-                                        shapelen=shapelen, sig=sig)
-            w_item = index._getitem_long(space, index_i.offset)
-            res.setitem(res_i.offset, concr.descr_getitem(space, w_item))
-            index_i = index_i.next(shapelen)
-            res_i = res_i.next(shapelen)
-        return res
-
-    def _getitem_long(self, space, offset):
-        # an obscure hack to not have longdtype inside a jitted loop
-        longdtype = interp_dtype.get_dtype_cache(space).w_longdtype
-        return self.getitem(offset).convert_to(longdtype).item(
-            space)
-
-    @jit.unroll_safe
-    def descr_item(self, space, w_arg=None):
-        if space.is_w(w_arg, space.w_None):
-            if isinstance(self, Scalar):
-                return self.value.item(space)
-            if support.product(self.shape) == 1:
-                return self.descr_getitem(space,
-                                          space.newtuple([space.wrap(0) for i
-                                                   in range(len(self.shape))]))
-            raise OperationError(space.w_ValueError,
-                                 space.wrap("index out of bounds"))
-        if space.isinstance_w(w_arg, space.w_int):
-            if isinstance(self, Scalar):
-                raise OperationError(space.w_ValueError, space.wrap("index out of bounds"))
-            concr = self.get_concrete()
-            i = to_coords(space, self.shape, concr.size, concr.order, w_arg)[0]
-            # XXX a bit around
-            item = self.descr_getitem(space, space.newtuple([space.wrap(x)
-                                             for x in i]))
-            assert isinstance(item, interp_boxes.W_GenericBox)
-            return item.item(space)
-        raise OperationError(space.w_NotImplementedError, space.wrap(
-            "non-int arg not supported"))
-
-    def descr_tostring(self, space):
-        ra = ToStringArray(self)
-        loop.compute(ra)
-        return space.wrap(ra.s.build())
-
-    def compute_first_step(self, sig, frame):
-        pass
-
-    @unwrap_spec(repeats=int)
-    def descr_repeat(self, space, repeats, w_axis=None):
-        return repeat(space, self, repeats, w_axis)
-
-def convert_to_array(space, w_obj):
-    if isinstance(w_obj, BaseArray):
-        return w_obj
-    elif space.issequence_w(w_obj):
-        # Convert to array.
-        return array(space, w_obj, w_order=None)
-    else:
-        # If it's a scalar
-        dtype = interp_ufuncs.find_dtype_for_scalar(space, w_obj)
-        return scalar_w(space, dtype, w_obj)
-
-def scalar_w(space, dtype, w_obj):
-    return Scalar(dtype, dtype.coerce(space, w_obj))
-
-class Scalar(BaseArray):
-    """
-    Intermediate class representing a literal.
-    """
-    _attrs_ = ["dtype", "value", "shape", "size"]
-
-    def __init__(self, dtype, value):
-        self.shape = []
-        BaseArray.__init__(self, [])
-        self.dtype = dtype
-        assert isinstance(value, interp_boxes.W_GenericBox)
-        self.value = value
-        self.size = dtype.get_size()
-
-    def find_dtype(self):
-        return self.dtype
-
-    def copy(self, space):
-        return Scalar(self.dtype, self.value)
-
-    def fill(self, space, w_value):
-        self.value = self.dtype.coerce(space, w_value)
-
-    def create_sig(self):
-        return signature.ScalarSignature(self.dtype)
-
-    def get_concrete_or_scalar(self):
-        return self
-
-    def reshape(self, space, new_shape):
-        res = W_NDimArray(new_shape, self.dtype, 'C')
-        res.setitem(0, self.value)
-        return res
-
-class VirtualArray(BaseArray):
-    """
-    Class for representing virtual arrays, such as binary ops or ufuncs
-    """
-    def __init__(self, name, shape, res_dtype, out_arg=None):
-        BaseArray.__init__(self, shape)
-        self.forced_result = None
-        self.res_dtype = res_dtype
-        self.name = name
-        self.res = out_arg
-        self.size = support.product(self.shape) * res_dtype.get_size()
-
-    def _del_sources(self):
-        # Function for deleting references to source arrays,
-        # to allow garbage-collecting them
-        raise NotImplementedError
-
-    def compute(self):
-        ra = ResultArray(self, self.shape, self.res_dtype, self.res)
-        loop.compute(ra)
-        if self.res:
-            broadcast_dims = len(self.res.shape) - len(self.shape)
-            chunks = [Chunk(0,0,0,0)] * broadcast_dims + \
-                     [Chunk(0, i, 1, i) for i in self.shape]
-            return Chunks(chunks).apply(self.res)
-        return ra.left
-
-    def force_if_needed(self):
-        if self.forced_result is None:
-            self.forced_result = self.compute().get_concrete()
-            self._del_sources()
-
-    def get_concrete(self):
-        self.force_if_needed()
-        res = self.forced_result
-        assert isinstance(res, ConcreteArray)
-        return res
-
-    def getitem(self, item):
-        return self.get_concrete().getitem(item)
-
-    def setitem(self, item, value):
-        return self.get_concrete().setitem(item, value)
-
-    def find_dtype(self):
-        return self.res_dtype
-
-class VirtualSlice(VirtualArray):
-    def __init__(self, child, chunks, shape):
-        self.child = child
-        self.chunks = chunks
-        VirtualArray.__init__(self, 'slice', shape, child.find_dtype())
-
-    def create_sig(self):
-        if self.forced_result is not None:
-            return self.forced_result.create_sig()
-        return signature.VirtualSliceSignature(
-            self.child.create_sig())
-
-    def force_if_needed(self):
-        if self.forced_result is None:
-            concr = self.child.get_concrete()
-            self.forced_result = self.chunks.apply(concr)
-
-    def _del_sources(self):
-        self.child = None
-
-
-class Call1(VirtualArray):
-    def __init__(self, ufunc, name, shape, calc_dtype, res_dtype, values,
-                                                            out_arg=None):
-        VirtualArray.__init__(self, name, shape, res_dtype, out_arg)
-        self.values = values
-        self.ufunc = ufunc
-        self.calc_dtype = calc_dtype
-
-    def _del_sources(self):
-        self.values = None
-
-    def create_sig(self):
-        if self.forced_result is not None:
-            return self.forced_result.create_sig()
-        if self.shape != self.values.shape:
-            #This happens if out arg is used
-            return signature.BroadcastUfunc(self.ufunc, self.name,
-                                            self.calc_dtype,
-                                            self.values.create_sig(),
-                                            self.res.create_sig())
-        return signature.Call1(self.ufunc, self.name, self.calc_dtype,
-                               self.values.create_sig())
-
-class Call2(VirtualArray):
-    """
-    Intermediate class for performing binary operations.
-    """
-    def __init__(self, ufunc, name, shape, calc_dtype, res_dtype, left, right,
-            out_arg=None):
-        VirtualArray.__init__(self, name, shape, res_dtype, out_arg)
-        self.ufunc = ufunc
-        self.left = left
-        self.right = right
-        self.calc_dtype = calc_dtype
-
-    def _del_sources(self):
-        self.left = None
-        self.right = None
-
-    def create_sig(self):
-        if self.forced_result is not None:
-            return self.forced_result.create_sig()
-        if self.shape != self.left.shape and self.shape != self.right.shape:
-            return signature.BroadcastBoth(self.ufunc, self.name,
-                                           self.calc_dtype,
-                                           self.left.create_sig(),
-                                           self.right.create_sig())
-        elif self.shape != self.left.shape:
-            return signature.BroadcastLeft(self.ufunc, self.name,
-                                           self.calc_dtype,
-                                           self.left.create_sig(),
-                                           self.right.create_sig())
-        elif self.shape != self.right.shape:
-            return signature.BroadcastRight(self.ufunc, self.name,
-                                            self.calc_dtype,
-                                            self.left.create_sig(),
-                                            self.right.create_sig())
-        return signature.Call2(self.ufunc, self.name, self.calc_dtype,
-                               self.left.create_sig(), self.right.create_sig())
-
-class ResultArray(Call2):
-    def __init__(self, child, shape, dtype, res=None, order='C'):
-        if res is None:
-            res = W_NDimArray(shape, dtype, order)
-        Call2.__init__(self, None, 'assign', shape, dtype, dtype, res, child)
-
-    def create_sig(self):
-        if self.left.shape != self.right.shape:
-            sig = signature.BroadcastResultSignature(self.res_dtype,
-                        self.left.create_sig(), self.right.create_sig())
-        else:
-            sig = signature.ResultSignature(self.res_dtype, 
-                        self.left.create_sig(), self.right.create_sig())
-        return sig
-
-class ToStringArray(Call1):
-    def __init__(self, child):
-        dtype = child.find_dtype()
-        self.item_size = dtype.itemtype.get_element_size()
-        self.s = StringBuilder(child.size * self.item_size)
-        Call1.__init__(self, None, 'tostring', child.shape, dtype, dtype,
-                       child)
-        self.res_str = W_NDimArray([1], dtype, order='C')
-        self.res_str_casted = rffi.cast(rffi.CArrayPtr(lltype.Char),
-                                    self.res_str.storage)
-
-    def create_sig(self):
-        return signature.ToStringSignature(self.calc_dtype,
-                                           self.values.create_sig())
-
-def done_if_true(dtype, val):
-    return dtype.itemtype.bool(val)
-
-def done_if_false(dtype, val):
-    return not dtype.itemtype.bool(val)
-
-class ReduceArray(Call2):
-    def __init__(self, func, name, identity, child, dtype):
-        self.identity = identity
-        Call2.__init__(self, func, name, [1], dtype, dtype, None, child)
-
-    def compute_first_step(self, sig, frame):
-        assert isinstance(sig, signature.ReduceSignature)
-        if self.identity is None:
-            frame.cur_value = sig.right.eval(frame, self.right).convert_to(
-                self.calc_dtype)
-            frame.next(len(self.right.shape))
-        else:
-            frame.cur_value = self.identity.convert_to(self.calc_dtype)
-
-    def create_sig(self):
-        if self.name == 'logical_and':
-            done_func = done_if_false
-        elif self.name == 'logical_or':
-            done_func = done_if_true
-        else:
-            done_func = None
-        return signature.ReduceSignature(self.ufunc, self.name, self.res_dtype,
-                                 signature.ScalarSignature(self.res_dtype),
-                                         self.right.create_sig(), done_func)
-
-class AxisReduce(Call2):
-    def __init__(self, ufunc, name, identity, shape, dtype, left, right, dim):
-        Call2.__init__(self, ufunc, name, shape, dtype, dtype,
-                       left, right)
-        self.dim = dim
-        self.identity = identity
-
-    def compute_first_step(self, sig, frame):
-        if self.identity is not None:
-            frame.identity = self.identity.convert_to(self.calc_dtype)
-
-    def create_sig(self):
-        return signature.AxisReduceSignature(self.ufunc, self.name,
-                                             self.res_dtype,
-                                 signature.ScalarSignature(self.res_dtype),
-                                             self.right.create_sig())
-
-class SliceArray(Call2):
-    def __init__(self, shape, dtype, left, right, no_broadcast=False):
-        self.no_broadcast = no_broadcast
-        Call2.__init__(self, None, 'sliceloop', shape, dtype, dtype, left,
-                       right)
-
-    def create_sig(self):
-        lsig = self.left.create_sig()
-        rsig = self.right.create_sig()
-        if not self.no_broadcast and self.shape != self.right.shape:
-            return signature.SliceloopBroadcastSignature(self.ufunc,
-                                                         self.name,
-                                                         self.calc_dtype,
-                                                         lsig, rsig)
-        return signature.SliceloopSignature(self.ufunc, self.name,
-                                            self.calc_dtype,
-                                            lsig, rsig)
-
-class ConcreteArray(BaseArray):
-    """ An array that have actual storage, whether owned or not
-    """
-    _immutable_fields_ = ['storage']
-
-    def __init__(self, shape, dtype, order='C', parent=None):
-        self.parent = parent
-        self.size = support.product(shape) * dtype.get_size()
-        if parent is not None:
-            self.storage = parent.storage
-        else:
-            self.storage = dtype.itemtype.malloc(self.size)
-        self.order = order
-        self.dtype = dtype
-        if self.strides is None:
-            self.calc_strides(shape)
-        BaseArray.__init__(self, shape)
-        if parent is not None:
-            self.invalidates = parent.invalidates
-
-    def get_concrete(self):
-        return self
-
-    def supports_fast_slicing(self):
-        return self.order == 'C' and self.strides[-1] == 1
-
-    def find_dtype(self):
-        return self.dtype
-
-    def getitem(self, item):
-        return self.dtype.getitem(self, item)
-
-    def setitem(self, item, value):
-        self.invalidated()
-        self.dtype.setitem(self, item, value.convert_to(self.dtype))
-
-    def calc_strides(self, shape):
-        dtype = self.find_dtype()
-        strides = []
-        backstrides = []
-        s = 1
-        shape_rev = shape[:]
-        if self.order == 'C':
-            shape_rev.reverse()
-        for sh in shape_rev:
-            strides.append(s * dtype.get_size())
-            backstrides.append(s * (sh - 1) * dtype.get_size())
-            s *= sh
-        if self.order == 'C':
-            strides.reverse()
-            backstrides.reverse()
-        self.strides = strides
-        self.backstrides = backstrides
-
-    @jit.unroll_safe
-    def _index_of_single_item(self, space, w_idx):
-        is_valid = False
-        try:
-            idx = space.int_w(space.index(w_idx))
-            is_valid = True
-        except OperationError:
-            pass
-
-        if not is_valid:
-            try:
-                idx = space.int_w(w_idx)
-                is_valid = True
-            except OperationError:
-                pass
-
-        if is_valid:
-            if idx < 0:
-                idx = self.shape[0] + idx
-            if idx < 0 or idx >= self.shape[0]:
-                raise OperationError(space.w_IndexError,
-                                     space.wrap("index out of range"))
-            return self.start + idx * self.strides[0]
-        index = [space.int_w(w_item)
-                 for w_item in space.fixedview(w_idx)]
-        item = self.start
-        for i in range(len(index)):
-            v = index[i]
-            if v < 0:
-                v += self.shape[i]
-            if v < 0 or v >= self.shape[i]:
-                raise operationerrfmt(space.w_IndexError,
-                    "index (%d) out of range (0<=index<%d", i, self.shape[i],
-                )
-            item += v * self.strides[i]
-        return item
-
-    def setslice(self, space, w_value):
-        res_shape = shape_agreement(space, self.shape, w_value.shape)
-        if (res_shape == w_value.shape and self.supports_fast_slicing() and
-            w_value.supports_fast_slicing() and
-            self.dtype is w_value.find_dtype()):
-            self._fast_setslice(space, w_value)
-        else:
-            arr = SliceArray(self.shape, self.dtype, self, w_value)
-            loop.compute(arr)
-
-    def _fast_setslice(self, space, w_value):
-        assert isinstance(w_value, ConcreteArray)
-        itemsize = self.dtype.itemtype.get_element_size()
-        shapelen = len(self.shape)
-        if shapelen == 1:
-            rffi.c_memcpy(
-                rffi.ptradd(self.storage, self.start),
-                rffi.ptradd(w_value.storage, w_value.start),
-                self.size
-            )
-        else:
-            dest = SkipLastAxisIterator(self)
-            source = SkipLastAxisIterator(w_value)
-            while not dest.done:
-                rffi.c_memcpy(
-                    rffi.ptradd(self.storage, dest.offset * itemsize),
-                    rffi.ptradd(w_value.storage, source.offset * itemsize),
-                    self.shape[-1] * itemsize
-                )
-                source.next()
-                dest.next()
-
-    def copy(self, space):
-        array = W_NDimArray(self.shape[:], self.dtype, self.order)
-        array.setslice(space, self)
-        return array
-
-    def fill(self, space, w_value):
-        self.setslice(space, scalar_w(space, self.dtype, w_value))
-
-
-class ViewArray(ConcreteArray):
-    def create_sig(self):
-        return signature.ViewSignature(self.dtype)
-
-
-class W_NDimSlice(ViewArray):
-    def __init__(self, start, strides, backstrides, shape, parent, dtype=None):
-        assert isinstance(parent, ConcreteArray)
-        if isinstance(parent, W_NDimSlice):
-            parent = parent.parent
-        self.strides = strides
-        self.backstrides = backstrides
-        if dtype is None:
-            dtype = parent.dtype
-        ViewArray.__init__(self, shape, dtype, parent.order, parent)
-        self.start = start
-
-    def create_iter(self, transforms=None):
-        return ViewIterator(self.start, self.strides, self.backstrides,
-                            self.shape).apply_transformations(self, transforms)
-
-    def setshape(self, space, new_shape):
-        if len(self.shape) < 1:
-            return
-        elif len(self.shape) < 2 or self.size < 1:
-            # TODO: this code could be refactored into calc_strides
-            # but then calc_strides would have to accept a stepping factor
-            strides = []
-            backstrides = []
-            dtype = self.find_dtype()
-            s = self.strides[0] // dtype.get_size()
-            if self.order == 'C':
-                new_shape.reverse()
-            for sh in new_shape:
-                strides.append(s * dtype.get_size())
-                backstrides.append(s * (sh - 1) * dtype.get_size())
-                s *= max(1, sh)
-            if self.order == 'C':
-                strides.reverse()
-                backstrides.reverse()
-                new_shape.reverse()
-            self.strides = strides
-            self.backstrides = backstrides
-            self.shape = new_shape
-            return
-        new_strides = calc_new_strides(new_shape, self.shape, self.strides,
-                                                   self.order)
-        if new_strides is None:
-            raise OperationError(space.w_AttributeError, space.wrap(
-                          "incompatible shape for a non-contiguous array"))
-        new_backstrides = [0] * len(new_shape)
-        for nd in range(len(new_shape)):
-            new_backstrides[nd] = (new_shape[nd] - 1) * new_strides[nd]
-        self.strides = new_strides[:]
-        self.backstrides = new_backstrides
-        self.shape = new_shape[:]
-
-class W_NDimArray(ConcreteArray):
-    """ A class representing contiguous array. We know that each iteration
-    by say ufunc will increase the data index by one
-    """
-    def setitem(self, item, value):
-        self.invalidated()
-        self.dtype.setitem(self, item, value)
-
-    def setshape(self, space, new_shape):
-        self.shape = new_shape
-        self.calc_strides(new_shape)
-
-    def create_iter(self, transforms=None):
-        esize = self.find_dtype().get_size()
-        return ArrayIterator(self.size, esize).apply_transformations(self,
-                                                                     transforms)
-
-    def create_sig(self):
-        return signature.ArraySignature(self.dtype)
-
-    def __del__(self):
-        free_raw_storage(self.storage, track_allocation=False)
-
-def _find_shape(space, w_size):
-    if space.isinstance_w(w_size, space.w_int):
-        return [space.int_w(w_size)]
-    shape = []
-    for w_item in space.fixedview(w_size):
-        shape.append(space.int_w(w_item))
-    return shape
-
- at unwrap_spec(subok=bool, copy=bool, ownmaskna=bool)
-def array(space, w_item_or_iterable, w_dtype=None, w_order=None,
-          subok=True, copy=True, w_maskna=None, ownmaskna=False,
-          w_ndmin=None):
-    # find scalar
-    if w_maskna is None:
-        w_maskna = space.w_None
-    if (not subok or not space.is_w(w_maskna, space.w_None) or
-        ownmaskna):
-        raise OperationError(space.w_NotImplementedError, space.wrap("Unsupported args"))
-    if not space.issequence_w(w_item_or_iterable):
+ at unwrap_spec(ndmin=int, copy=bool, subok=bool)
+def array(space, w_object, w_dtype=None, copy=True, w_order=None, subok=False,
+          ndmin=0):
+    if not space.issequence_w(w_object):
         if w_dtype is None or space.is_w(w_dtype, space.w_None):
-            w_dtype = interp_ufuncs.find_dtype_for_scalar(space,
-                                                          w_item_or_iterable)
+            w_dtype = interp_ufuncs.find_dtype_for_scalar(space, w_object)
         dtype = space.interp_w(interp_dtype.W_Dtype,
-            space.call_function(space.gettypefor(interp_dtype.W_Dtype), w_dtype)
-        )
-        return scalar_w(space, dtype, w_item_or_iterable)
-    if space.is_w(w_order, space.w_None) or w_order is None:
+          space.call_function(space.gettypefor(interp_dtype.W_Dtype), w_dtype))
+        return W_NDimArray.new_scalar(space, dtype, w_object)
+    if w_order is None or space.is_w(w_order, space.w_None):
         order = 'C'
     else:
         order = space.str_w(w_order)
         if order != 'C':  # or order != 'F':
             raise operationerrfmt(space.w_ValueError, "Unknown order: %s",
                                   order)
-    if isinstance(w_item_or_iterable, BaseArray):
+    if isinstance(w_object, W_NDimArray):
         if (not space.is_w(w_dtype, space.w_None) and
-            w_item_or_iterable.find_dtype() is not w_dtype):
+            w_object.get_dtype() is not w_dtype):
             raise OperationError(space.w_NotImplementedError, space.wrap(
-                "copying over different dtypes unsupported"))
+                                  "copying over different dtypes unsupported"))
         if copy:
-            return w_item_or_iterable.copy(space)
-        return w_item_or_iterable
-    if w_dtype is None or space.is_w(w_dtype, space.w_None):
-        dtype = None
-    else:
-        dtype = space.interp_w(interp_dtype.W_Dtype,
-           space.call_function(space.gettypefor(interp_dtype.W_Dtype), w_dtype))
-    shape, elems_w = find_shape_and_elems(space, w_item_or_iterable, dtype)
-    # they come back in C order
+            return w_object.descr_copy(space)
+        return w_object
+    dtype = interp_dtype.decode_w_dtype(space, w_dtype)
+    shape, elems_w = find_shape_and_elems(space, w_object, dtype)
     if dtype is None:
         for w_elem in elems_w:
             dtype = interp_ufuncs.find_dtype_for_scalar(space, w_elem,
@@ -1267,378 +589,54 @@
                 break
         if dtype is None:
             dtype = interp_dtype.get_dtype_cache(space).w_float64dtype
-    shapelen = len(shape)
-    if w_ndmin is not None and not space.is_w(w_ndmin, space.w_None):
-        ndmin = space.int_w(w_ndmin)
-        if ndmin > shapelen:
-            shape = [1] * (ndmin - shapelen) + shape
-            shapelen = ndmin
-    arr = W_NDimArray(shape[:], dtype=dtype, order=order)
-    arr_iter = arr.create_iter()
-    # XXX we might want to have a jitdriver here
-    for i in range(len(elems_w)):
-        w_elem = elems_w[i]
-        dtype.setitem(arr, arr_iter.offset,
-                      dtype.coerce(space, w_elem))
-        arr_iter = arr_iter.next(shapelen)
+    if ndmin > len(shape):
+        shape = [1] * (ndmin - len(shape)) + shape
+    arr = W_NDimArray.from_shape(shape, dtype, order=order)
+    arr_iter = arr.create_iter(arr.get_shape())
+    for w_elem in elems_w:
+        arr_iter.setitem(dtype.coerce(space, w_elem))
+        arr_iter.next()
     return arr
 
-def zeros(space, w_size, w_dtype=None):
+ at unwrap_spec(order=str)
+def zeros(space, w_shape, w_dtype=None, order='C'):
     dtype = space.interp_w(interp_dtype.W_Dtype,
         space.call_function(space.gettypefor(interp_dtype.W_Dtype), w_dtype)
     )
-    shape = _find_shape(space, w_size)
+    shape = _find_shape(space, w_shape)
     if not shape:
-        return scalar_w(space, dtype, space.wrap(0))
-    return space.wrap(W_NDimArray(shape[:], dtype=dtype))
+        return W_NDimArray.new_scalar(space, dtype, space.wrap(0))
+    return space.wrap(W_NDimArray.from_shape(shape, dtype=dtype, order=order))
 
-def ones(space, w_size, w_dtype=None):
+ at unwrap_spec(order=str)
+def ones(space, w_shape, w_dtype=None, order='C'):
     dtype = space.interp_w(interp_dtype.W_Dtype,
         space.call_function(space.gettypefor(interp_dtype.W_Dtype), w_dtype)
     )
-
-    shape = _find_shape(space, w_size)
+    shape = _find_shape(space, w_shape)
     if not shape:
-        return scalar_w(space, dtype, space.wrap(1))
-    arr = W_NDimArray(shape[:], dtype=dtype)
+        return W_NDimArray.new_scalar(space, dtype, space.wrap(0))
+    arr = W_NDimArray.from_shape(shape, dtype=dtype, order=order)
     one = dtype.box(1)
-    arr.dtype.fill(arr.storage, one, 0, arr.size)
+    arr.fill(one)
     return space.wrap(arr)
 
- at unwrap_spec(arr=BaseArray, skipna=bool, keepdims=bool)
-def count_reduce_items(space, arr, w_axis=None, skipna=False, keepdims=True):
-    if not keepdims:
-        raise OperationError(space.w_NotImplementedError, space.wrap("unsupported"))
-    if space.is_w(w_axis, space.w_None):
-        return space.wrap(support.product(arr.shape))
-    shapelen = len(arr.shape)
-    if space.isinstance_w(w_axis, space.w_int):
-        axis = space.int_w(w_axis)
-        if axis < -shapelen or axis>= shapelen:
-            raise operationerrfmt(space.w_ValueError,
-                "axis entry %d is out of bounds [%d, %d)", axis,
-                -shapelen, shapelen)
-        return space.wrap(arr.shape[axis])    
-    # numpy as of June 2012 does not implement this 
-    s = 1
-    elems = space.fixedview(w_axis)
-    for w_elem in elems:
-        axis = space.int_w(w_elem)
-        if axis < -shapelen or axis>= shapelen:
-            raise operationerrfmt(space.w_ValueError,
-                "axis entry %d is out of bounds [%d, %d)", axis,
-                -shapelen, shapelen)
-        s *= arr.shape[axis]
-    return space.wrap(s)
-
-def dot(space, w_obj, w_obj2):
-    '''see numpypy.dot. Does not exist as an ndarray method in numpy.
-    '''
-    w_arr = convert_to_array(space, w_obj)
-    if isinstance(w_arr, Scalar):
-        return convert_to_array(space, w_obj2).descr_dot(space, w_arr)
-    return w_arr.descr_dot(space, w_obj2)
-
- at unwrap_spec(repeats=int)
-def repeat(space, w_arr, repeats, w_axis=None):
-    arr = convert_to_array(space, w_arr)
-    if space.is_w(w_axis, space.w_None):
-        arr = arr.descr_flatten(space).get_concrete()
-        orig_size = arr.shape[0]
-        shape = [arr.shape[0] * repeats]
-        res = W_NDimArray(shape, arr.find_dtype())
-        for i in range(repeats):
-            Chunks([Chunk(i, shape[0] - repeats + i, repeats,
-                          orig_size)]).apply(res).setslice(space, arr)
-    else:
-        arr = arr.get_concrete()
-        axis = space.int_w(w_axis)
-        shape = arr.shape[:]
-        chunks = [Chunk(0, i, 1, i) for i in shape]
-        orig_size = shape[axis]
-        shape[axis] *= repeats
-        res = W_NDimArray(shape, arr.find_dtype())
-        for i in range(repeats):
-            chunks[axis] = Chunk(i, shape[axis] - repeats + i, repeats,
-                                 orig_size)
-            Chunks(chunks).apply(res).setslice(space, arr)
-    return res
-
- at unwrap_spec(axis=int)
-def concatenate(space, w_args, axis=0):
-    args_w = space.listview(w_args)
-    if len(args_w) == 0:
-        raise OperationError(space.w_ValueError, space.wrap("concatenation of zero-length sequences is impossible"))
-    args_w = [convert_to_array(space, w_arg) for w_arg in args_w]
-    dtype = args_w[0].find_dtype()
-    shape = args_w[0].shape[:]
-    if len(shape) <= axis:
-        raise OperationError(space.w_ValueError,
-                             space.wrap("bad axis argument"))
-    for arr in args_w[1:]:
-        dtype = interp_ufuncs.find_binop_result_dtype(space, dtype,
-                                                      arr.find_dtype())
-        if len(arr.shape) <= axis:
-            raise OperationError(space.w_ValueError,
-                                 space.wrap("bad axis argument"))
-        for i, axis_size in enumerate(arr.shape):
-            if len(arr.shape) != len(shape) or (i != axis and axis_size != shape[i]):
-                raise OperationError(space.w_ValueError, space.wrap(
-                    "array dimensions must agree except for axis being concatenated"))
-            elif i == axis:
-                shape[i] += axis_size
-    res = W_NDimArray(shape, dtype, 'C')
-    chunks = [Chunk(0, i, 1, i) for i in shape]
-    axis_start = 0
-    for arr in args_w:
-        chunks[axis] = Chunk(axis_start, axis_start + arr.shape[axis], 1,
-                             arr.shape[axis])
-        Chunks(chunks).apply(res).setslice(space, arr)
-        axis_start += arr.shape[axis]
-    return res
-
-BaseArray.typedef = TypeDef(
-    'ndarray',
-    __module__ = "numpypy",
-    __new__ = interp2app(BaseArray.descr__new__.im_func),
-
-    __len__ = interp2app(BaseArray.descr_len),
-    __getitem__ = interp2app(BaseArray.descr_getitem),
-    __setitem__ = interp2app(BaseArray.descr_setitem),
-
-    __pos__ = interp2app(BaseArray.descr_pos),
-    __neg__ = interp2app(BaseArray.descr_neg),
-    __abs__ = interp2app(BaseArray.descr_abs),
-    __invert__ = interp2app(BaseArray.descr_invert),
-    __nonzero__ = interp2app(BaseArray.descr_nonzero),
-
-    __add__ = interp2app(BaseArray.descr_add),
-    __sub__ = interp2app(BaseArray.descr_sub),
-    __mul__ = interp2app(BaseArray.descr_mul),
-    __div__ = interp2app(BaseArray.descr_div),
-    __truediv__ = interp2app(BaseArray.descr_truediv),
-    __floordiv__ = interp2app(BaseArray.descr_floordiv),
-    __mod__ = interp2app(BaseArray.descr_mod),
-    __divmod__ = interp2app(BaseArray.descr_divmod),
-    __pow__ = interp2app(BaseArray.descr_pow),
-    __lshift__ = interp2app(BaseArray.descr_lshift),
-    __rshift__ = interp2app(BaseArray.descr_rshift),
-    __and__ = interp2app(BaseArray.descr_and),
-    __or__ = interp2app(BaseArray.descr_or),
-    __xor__ = interp2app(BaseArray.descr_xor),
-
-    __radd__ = interp2app(BaseArray.descr_radd),
-    __rsub__ = interp2app(BaseArray.descr_rsub),
-    __rmul__ = interp2app(BaseArray.descr_rmul),
-    __rdiv__ = interp2app(BaseArray.descr_rdiv),
-    __rtruediv__ = interp2app(BaseArray.descr_rtruediv),
-    __rfloordiv__ = interp2app(BaseArray.descr_rfloordiv),
-    __rmod__ = interp2app(BaseArray.descr_rmod),
-    __rdivmod__ = interp2app(BaseArray.descr_rdivmod),
-    __rpow__ = interp2app(BaseArray.descr_rpow),
-    __rlshift__ = interp2app(BaseArray.descr_rlshift),
-    __rrshift__ = interp2app(BaseArray.descr_rrshift),
-    __rand__ = interp2app(BaseArray.descr_rand),
-    __ror__ = interp2app(BaseArray.descr_ror),
-    __rxor__ = interp2app(BaseArray.descr_rxor),
-
-    __eq__ = interp2app(BaseArray.descr_eq),
-    __ne__ = interp2app(BaseArray.descr_ne),
-    __lt__ = interp2app(BaseArray.descr_lt),
-    __le__ = interp2app(BaseArray.descr_le),
-    __gt__ = interp2app(BaseArray.descr_gt),
-    __ge__ = interp2app(BaseArray.descr_ge),
-
-    __repr__ = interp2app(BaseArray.descr_repr),
-    __str__ = interp2app(BaseArray.descr_str),
-    __array_interface__ = GetSetProperty(BaseArray.descr_array_iface),
-
-    dtype = GetSetProperty(BaseArray.descr_get_dtype),
-    shape = GetSetProperty(BaseArray.descr_get_shape,
-                           BaseArray.descr_set_shape),
-    size = GetSetProperty(BaseArray.descr_get_size),
-    ndim = GetSetProperty(BaseArray.descr_get_ndim),
-    itemsize = GetSetProperty(BaseArray.descr_get_itemsize),
-    nbytes = GetSetProperty(BaseArray.descr_get_nbytes),
-
-    T = GetSetProperty(BaseArray.descr_get_transpose),
-    transpose = interp2app(BaseArray.descr_get_transpose),
-    flat = GetSetProperty(BaseArray.descr_get_flatiter),
-    ravel = interp2app(BaseArray.descr_ravel),
-    item = interp2app(BaseArray.descr_item),
-
-    mean = interp2app(BaseArray.descr_mean),
-    sum = interp2app(BaseArray.descr_sum),
-    prod = interp2app(BaseArray.descr_prod),
-    max = interp2app(BaseArray.descr_max),
-    min = interp2app(BaseArray.descr_min),
-    argmax = interp2app(BaseArray.descr_argmax),
-    argmin = interp2app(BaseArray.descr_argmin),
-    all = interp2app(BaseArray.descr_all),
-    any = interp2app(BaseArray.descr_any),
-    dot = interp2app(BaseArray.descr_dot),
-    var = interp2app(BaseArray.descr_var),
-    std = interp2app(BaseArray.descr_std),
-
-    fill = interp2app(BaseArray.descr_fill),
-    tostring = interp2app(BaseArray.descr_tostring),
-
-    copy = interp2app(BaseArray.descr_copy),
-    flatten = interp2app(BaseArray.descr_flatten),
-    reshape = interp2app(BaseArray.descr_reshape),
-    swapaxes = interp2app(BaseArray.descr_swapaxes),
-    tolist = interp2app(BaseArray.descr_tolist),
-    take = interp2app(BaseArray.descr_take),
-    compress = interp2app(BaseArray.descr_compress),
-    repeat = interp2app(BaseArray.descr_repeat),
-    count_nonzero = interp2app(BaseArray.descr_count_nonzero),
-)
-
-
-class W_FlatIterator(ViewArray):
-
-    @jit.unroll_safe
-    def __init__(self, arr):
-        arr = arr.get_concrete()
-        self.strides = [arr.strides[-1]]
-        self.backstrides = [arr.backstrides[-1]]
-        self.shapelen = len(arr.shape)
-        sig = arr.find_sig()
-        self.iter = sig.create_frame(arr).get_final_iter()
-        self.base = arr
-        self.index = 0
-        ViewArray.__init__(self, [arr.get_size()], arr.dtype, arr.order,
-                           arr)
-
-    def descr_next(self, space):
-        if self.iter.done():
-            raise OperationError(space.w_StopIteration, space.w_None)
-        result = self.base.getitem(self.iter.offset)
-        self.iter = self.iter.next(self.shapelen)
-        self.index += 1
-        return result
-
-    def descr_iter(self):
-        return self
-
-    def descr_len(self, space):
-        return space.wrap(self.get_size())
-
-    def descr_index(self, space):
-        return space.wrap(self.index)
-
-    def descr_coords(self, space):
-        coords, step, lngth = to_coords(space, self.base.shape,
-                            self.base.size, self.base.order,
-                            space.wrap(self.index))
-        return space.newtuple([space.wrap(c) for c in coords])
-
-    @jit.unroll_safe
-    def descr_getitem(self, space, w_idx):
-        if not (space.isinstance_w(w_idx, space.w_int) or
-            space.isinstance_w(w_idx, space.w_slice)):
-            raise OperationError(space.w_IndexError,
-                                 space.wrap('unsupported iterator index'))
-        base = self.base
-        start, stop, step, lngth = space.decode_index4(w_idx, base.get_size())
-        # setslice would have been better, but flat[u:v] for arbitrary
-        # shapes of array a cannot be represented as a[x1:x2, y1:y2]
-        basei = ViewIterator(base.start, base.strides,
-                             base.backstrides, base.shape)
-        shapelen = len(base.shape)
-        basei = basei.next_skip_x(shapelen, start)
-        if lngth <2:
-            return base.getitem(basei.offset)
-        res = W_NDimArray([lngth], base.dtype, base.order)
-        ri = res.create_iter()
-        while not ri.done():
-            flat_get_driver.jit_merge_point(shapelen=shapelen,
-                                             base=base,
-                                             basei=basei,
-                                             step=step,
-                                             res=res,
-                                             ri=ri)
-            w_val = base.getitem(basei.offset)
-            res.setitem(ri.offset, w_val)
-            basei = basei.next_skip_x(shapelen, step)
-            ri = ri.next(shapelen)
-        return res
-
-    def descr_setitem(self, space, w_idx, w_value):
-        if not (space.isinstance_w(w_idx, space.w_int) or
-            space.isinstance_w(w_idx, space.w_slice)):
-            raise OperationError(space.w_IndexError,
-                                 space.wrap('unsupported iterator index'))
-        base = self.base
-        start, stop, step, lngth = space.decode_index4(w_idx, base.get_size())
-        arr = convert_to_array(space, w_value)
-        ri = arr.create_iter()
-        basei = ViewIterator(base.start, base.strides,
-                             base.backstrides, base.shape)
-        shapelen = len(base.shape)
-        basei = basei.next_skip_x(shapelen, start)
-        while lngth > 0:
-            flat_set_driver.jit_merge_point(shapelen=shapelen,
-                                            basei=basei,
-                                            base=base,
-                                            step=step,
-                                            arr=arr,
-                                            lngth=lngth,
-                                            ri=ri)
-            v = arr.getitem(ri.offset).convert_to(base.dtype)
-            base.setitem(basei.offset, v)
-            # need to repeat input values until all assignments are done
-            basei = basei.next_skip_x(shapelen, step)
-            ri = ri.next(shapelen)
-            # WTF is numpy thinking?
-            ri.offset %= arr.size
-            lngth -= 1
-
-    def create_sig(self):
-        return signature.FlatSignature(self.base.dtype)
-
-    def create_iter(self, transforms=None):
-        return ViewIterator(self.base.start, self.base.strides,
-                            self.base.backstrides,
-                            self.base.shape).apply_transformations(self.base,
-                                                                   transforms)
-
-    def descr_base(self, space):
-        return space.wrap(self.base)
-
 W_FlatIterator.typedef = TypeDef(
     'flatiter',
     __iter__ = interp2app(W_FlatIterator.descr_iter),
-    __len__ = interp2app(W_FlatIterator.descr_len),
     __getitem__ = interp2app(W_FlatIterator.descr_getitem),
     __setitem__ = interp2app(W_FlatIterator.descr_setitem),
+    __len__ = interp2app(W_FlatIterator.descr_len),
 
-    __eq__ = interp2app(BaseArray.descr_eq),
-    __ne__ = interp2app(BaseArray.descr_ne),
-    __lt__ = interp2app(BaseArray.descr_lt),
-    __le__ = interp2app(BaseArray.descr_le),
-    __gt__ = interp2app(BaseArray.descr_gt),
-    __ge__ = interp2app(BaseArray.descr_ge),
+    __eq__ = interp2app(W_FlatIterator.descr_eq),
+    __ne__ = interp2app(W_FlatIterator.descr_ne),
+    __lt__ = interp2app(W_FlatIterator.descr_lt),
+    __le__ = interp2app(W_FlatIterator.descr_le),
+    __gt__ = interp2app(W_FlatIterator.descr_gt),
+    __ge__ = interp2app(W_FlatIterator.descr_ge),
 
+    next = interp2app(W_FlatIterator.descr_next),
     base = GetSetProperty(W_FlatIterator.descr_base),
     index = GetSetProperty(W_FlatIterator.descr_index),
     coords = GetSetProperty(W_FlatIterator.descr_coords),
-    next = interp2app(W_FlatIterator.descr_next),
-
 )
-W_FlatIterator.acceptable_as_base_class = False
-
-def isna(space, w_obj):
-    if isinstance(w_obj, BaseArray):
-        arr = w_obj.empty_copy(space,
-                               interp_dtype.get_dtype_cache(space).w_booldtype)
-        arr.fill(space, space.wrap(False))
-        return arr
-    return space.wrap(False)
-
-class NumArrayCache(object):
-    def __init__(self, space):
-        self.enable_invalidation = True
-
-def get_numarray_cache(space):
-    return space.fromcache(NumArrayCache)
diff --git a/pypy/module/micronumpy/interp_support.py b/pypy/module/micronumpy/interp_support.py
--- a/pypy/module/micronumpy/interp_support.py
+++ b/pypy/module/micronumpy/interp_support.py
@@ -1,16 +1,14 @@
 from pypy.interpreter.error import OperationError, operationerrfmt
 from pypy.interpreter.gateway import unwrap_spec
 from pypy.rpython.lltypesystem import lltype, rffi
-from pypy.module.micronumpy import interp_dtype
+from pypy.module.micronumpy import interp_dtype, loop
 from pypy.objspace.std.strutil import strip_spaces
-from pypy.rlib import jit
 from pypy.rlib.rarithmetic import maxint
+from pypy.module.micronumpy.base import W_NDimArray
 
 FLOAT_SIZE = rffi.sizeof(lltype.Float)
 
 def _fromstring_text(space, s, count, sep, length, dtype):
-    from pypy.module.micronumpy.interp_numarray import W_NDimArray
-
     sep_stripped = strip_spaces(sep)
     skip_bad_vals = len(sep_stripped) == 0
 
@@ -52,17 +50,15 @@
         raise OperationError(space.w_ValueError, space.wrap(
             "string is smaller than requested size"))
 
-    a = W_NDimArray([num_items], dtype=dtype)
+    a = W_NDimArray.from_shape([num_items], dtype=dtype)
     ai = a.create_iter()
     for val in items:
-        a.dtype.setitem(a, ai.offset, val)
-        ai = ai.next(1)
-    
+        ai.setitem(val)
+        ai.next()
+
     return space.wrap(a)
 
 def _fromstring_bin(space, s, count, length, dtype):
-    from pypy.module.micronumpy.interp_numarray import W_NDimArray
-    
     itemsize = dtype.itemtype.get_element_size()
     assert itemsize >= 0
     if count == -1:
@@ -75,25 +71,10 @@
         raise OperationError(space.w_ValueError, space.wrap(
             "string is smaller than requested size"))
         
-    a = W_NDimArray([count], dtype=dtype)
-    fromstring_loop(a, dtype, itemsize, s)
+    a = W_NDimArray.from_shape([count], dtype=dtype)
+    loop.fromstring_loop(a, dtype, itemsize, s)
     return space.wrap(a)
 
-fromstring_driver = jit.JitDriver(greens=[], reds=['i', 'itemsize',
-                                                   'dtype', 'ai', 's', 'a'])
-
-def fromstring_loop(a, dtype, itemsize, s):
-    i = 0
-    ai = a.create_iter()
-    while not ai.done():
-        fromstring_driver.jit_merge_point(a=a, dtype=dtype,
-                                          itemsize=itemsize, s=s, i=i,
-                                          ai=ai)
-        val = dtype.itemtype.runpack_str(s[i*itemsize:i*itemsize + itemsize])
-        a.dtype.setitem(a, ai.offset, val)
-        ai = ai.next(1)
-        i += 1
-
 @unwrap_spec(s=str, count=int, sep=str)
 def fromstring(space, s, w_dtype=None, count=-1, sep=''):
     dtype = space.interp_w(interp_dtype.W_Dtype,
diff --git a/pypy/module/micronumpy/interp_ufuncs.py b/pypy/module/micronumpy/interp_ufuncs.py
--- a/pypy/module/micronumpy/interp_ufuncs.py
+++ b/pypy/module/micronumpy/interp_ufuncs.py
@@ -7,6 +7,14 @@
 from pypy.rlib.rarithmetic import LONG_BIT
 from pypy.tool.sourcetools import func_with_new_name
 from pypy.module.micronumpy.interp_support import unwrap_axis_arg
+from pypy.module.micronumpy.strides import shape_agreement
+from pypy.module.micronumpy.base import convert_to_array, W_NDimArray
+
+def done_if_true(dtype, val):
+    return dtype.itemtype.bool(val)
+
+def done_if_false(dtype, val):
+    return not dtype.itemtype.bool(val)
 
 class W_Ufunc(Wrappable):
     _attrs_ = ["name", "promote_to_float", "promote_bools", "identity"]
@@ -30,7 +38,6 @@
         return self.identity
 
     def descr_call(self, space, __args__):
-        from interp_numarray import BaseArray
         args_w, kwds_w = __args__.unpack()
         # it occurs to me that we don't support any datatypes that
         # require casting, change it later when we do
@@ -58,8 +65,8 @@
         if len(args_w) > self.argcount:
             out = args_w[-1]
         else:
-            args_w = args_w[:] + [out]
-        if out is not None and not isinstance(out, BaseArray):
+            args_w = args_w + [out]
+        if out is not None and not isinstance(out, W_NDimArray):
             raise OperationError(space.w_TypeError, space.wrap(
                                             'output must be an array'))
         return self.call(space, args_w)
@@ -119,97 +126,88 @@
         array([[ 1,  5],
                [ 9, 13]])
         """
-        from pypy.module.micronumpy.interp_numarray import BaseArray
+        from pypy.module.micronumpy.interp_numarray import W_NDimArray
         if w_axis is None:
             w_axis = space.wrap(0)
         if space.is_w(w_out, space.w_None):
             out = None
-        elif not isinstance(w_out, BaseArray):
+        elif not isinstance(w_out, W_NDimArray):
             raise OperationError(space.w_TypeError, space.wrap(
                                                 'output must be an array'))
         else:
             out = w_out
-        return self.reduce(space, w_obj, False, False, w_axis, keepdims, out)
+        return self.reduce(space, w_obj, False, False, w_axis, keepdims, out,
+                           w_dtype)
 
     def reduce(self, space, w_obj, multidim, promote_to_largest, w_axis,
-               keepdims=False, out=None):
-        from pypy.module.micronumpy.interp_numarray import convert_to_array, \
-                                             Scalar, ReduceArray, W_NDimArray
+               keepdims=False, out=None, dtype=None):
         if self.argcount != 2:
             raise OperationError(space.w_ValueError, space.wrap("reduce only "
                 "supported for binary functions"))
         assert isinstance(self, W_Ufunc2)
         obj = convert_to_array(space, w_obj)
-        if isinstance(obj, Scalar):
-            raise OperationError(space.w_TypeError, space.wrap("cannot reduce "
-                "on a scalar"))
-        axis = unwrap_axis_arg(space, len(obj.shape), w_axis)    
+        obj_shape = obj.get_shape()
+        if obj.is_scalar():
+            return obj.get_scalar_value()
+        shapelen = len(obj_shape)
+        axis = unwrap_axis_arg(space, shapelen, w_axis)    
         assert axis>=0
-        size = obj.size
-        if self.comparison_func:
-            dtype = interp_dtype.get_dtype_cache(space).w_booldtype
-        else:
-            dtype = find_unaryop_result_dtype(
-                space, obj.find_dtype(),
-                promote_to_float=self.promote_to_float,
-                promote_to_largest=promote_to_largest,
-                promote_bools=True
-            )
-        shapelen = len(obj.shape)
+        size = obj.get_size()
+        dtype = interp_dtype.decode_w_dtype(space, dtype)
+        if dtype is None:
+            if self.comparison_func:
+                dtype = interp_dtype.get_dtype_cache(space).w_booldtype
+            else:
+                dtype = find_unaryop_result_dtype(
+                    space, obj.get_dtype(),
+                    promote_to_float=self.promote_to_float,
+                    promote_to_largest=promote_to_largest,
+                    promote_bools=True
+                )
         if self.identity is None and size == 0:
             raise operationerrfmt(space.w_ValueError, "zero-size array to "
                     "%s.reduce without identity", self.name)
         if shapelen > 1 and axis < shapelen:
             if keepdims:
-                shape = obj.shape[:axis] + [1] + obj.shape[axis + 1:]
+                shape = obj_shape[:axis] + [1] + obj_shape[axis + 1:]
             else:
-                shape = obj.shape[:axis] + obj.shape[axis + 1:]
+                shape = obj_shape[:axis] + obj_shape[axis + 1:]
             if out:
-                #Test for shape agreement
-                if len(out.shape) > len(shape):
+                # Test for shape agreement
+                # XXX maybe we need to do broadcasting here, although I must
+                #     say I don't understand the details for axis reduce
+                if len(out.get_shape()) > len(shape):
                     raise operationerrfmt(space.w_ValueError,
                         'output parameter for reduction operation %s' +
                         ' has too many dimensions', self.name)
-                elif len(out.shape) < len(shape):
+                elif len(out.get_shape()) < len(shape):
                     raise operationerrfmt(space.w_ValueError,
                         'output parameter for reduction operation %s' +
                         ' does not have enough dimensions', self.name)
-                elif out.shape != shape:
+                elif out.get_shape() != shape:
                     raise operationerrfmt(space.w_ValueError,
                         'output parameter shape mismatch, expecting [%s]' +
                         ' , got [%s]',
                         ",".join([str(x) for x in shape]),
-                        ",".join([str(x) for x in out.shape]),
+                        ",".join([str(x) for x in out.get_shape()]),
                         )
-                #Test for dtype agreement, perhaps create an itermediate
-                #if out.dtype != dtype:
-                #    raise OperationError(space.w_TypeError, space.wrap(
-                #        "mismatched  dtypes"))
-                return self.do_axis_reduce(obj, out.find_dtype(), axis, out)
+                dtype = out.get_dtype()
             else:
-                result = W_NDimArray(shape, dtype)
-                return self.do_axis_reduce(obj, dtype, axis, result)
+                out = W_NDimArray.from_shape(shape, dtype)
+            return loop.do_axis_reduce(shape, self.func, obj, dtype, axis, out,
+                                       self.identity)
         if out:
-            if len(out.shape)>0:
+            if len(out.get_shape())>0:
                 raise operationerrfmt(space.w_ValueError, "output parameter "
                               "for reduction operation %s has too many"
                               " dimensions",self.name)
-            arr = ReduceArray(self.func, self.name, self.identity, obj,
-                                                            out.find_dtype())
-            val = loop.compute(arr)
-            assert isinstance(out, Scalar)
-            out.value = val
-        else:
-            arr = ReduceArray(self.func, self.name, self.identity, obj, dtype)
-            val = loop.compute(arr)
-        return val
-
-    def do_axis_reduce(self, obj, dtype, axis, result):
-        from pypy.module.micronumpy.interp_numarray import AxisReduce
-        arr = AxisReduce(self.func, self.name, self.identity, obj.shape, dtype,
-                         result, obj, axis)
-        loop.compute(arr)
-        return arr.left
+            dtype = out.get_dtype()
+        res = loop.compute_reduce(obj, dtype, self.func, self.done_func,
+                                  self.identity)
+        if out:
+            out.set_scalar_value(res)
+            return out
+        return res
 
 class W_Ufunc1(W_Ufunc):
     argcount = 1
@@ -225,57 +223,43 @@
         self.bool_result = bool_result
 
     def call(self, space, args_w):
-        from pypy.module.micronumpy.interp_numarray import (Call1, BaseArray,
-            convert_to_array, Scalar, shape_agreement)
-        if len(args_w)<2:
-            [w_obj] = args_w
-            out = None
-        else:
-            [w_obj, out] = args_w
+        w_obj = args_w[0]
+        out = None
+        if len(args_w) > 1:
+            out = args_w[1]
             if space.is_w(out, space.w_None):
                 out = None
         w_obj = convert_to_array(space, w_obj)
         calc_dtype = find_unaryop_result_dtype(space,
-                                  w_obj.find_dtype(),
+                                  w_obj.get_dtype(),
                                   promote_to_float=self.promote_to_float,
                                   promote_bools=self.promote_bools)
-        if out:
-            if not isinstance(out, BaseArray):
+        if out is not None:
+            if not isinstance(out, W_NDimArray):
                 raise OperationError(space.w_TypeError, space.wrap(
                                                 'output must be an array'))
-            res_dtype = out.find_dtype()
+            res_dtype = out.get_dtype()
+            #if not w_obj.get_dtype().can_cast_to(res_dtype):
+            #    raise operationerrfmt(space.w_TypeError,
+            #        "Cannot cast ufunc %s output from dtype('%s') to dtype('%s') with casting rule 'same_kind'", self.name, w_obj.get_dtype().name, res_dtype.name)
         elif self.bool_result:
             res_dtype = interp_dtype.get_dtype_cache(space).w_booldtype
         else:
             res_dtype = calc_dtype
-        if isinstance(w_obj, Scalar):
-            arr = self.func(calc_dtype, w_obj.value.convert_to(calc_dtype))
-            if isinstance(out,Scalar):
-                out.value = arr
-            elif isinstance(out, BaseArray):
-                out.fill(space, arr)
+        if w_obj.is_scalar():
+            w_val = self.func(calc_dtype,
+                              w_obj.get_scalar_value().convert_to(calc_dtype))
+            if out is None:
+                return w_val
+            if out.is_scalar():
+                out.set_scalar_value(w_val)
             else:
-                out = arr
-            return space.wrap(out)
-        if out:
-            assert isinstance(out, BaseArray) # For translation
-            broadcast_shape =  shape_agreement(space, w_obj.shape, out.shape)
-            if not broadcast_shape or broadcast_shape != out.shape:
-                raise operationerrfmt(space.w_ValueError,
-                    'output parameter shape mismatch, could not broadcast [%s]' +
-                    ' to [%s]',
-                    ",".join([str(x) for x in w_obj.shape]),
-                    ",".join([str(x) for x in out.shape]),
-                    )
-            w_res = Call1(self.func, self.name, out.shape, calc_dtype,
-                                         res_dtype, w_obj, out)
-            #Force it immediately
-            w_res.get_concrete()
-        else:
-            w_res = Call1(self.func, self.name, w_obj.shape, calc_dtype,
-                                         res_dtype, w_obj)
-        w_obj.add_invalidates(space, w_res)
-        return w_res
+                out.fill(res_dtype.coerce(space, w_val))
+            return out
+        shape = shape_agreement(space, w_obj.get_shape(), out,
+                                broadcast_down=False)
+        return loop.call1(shape, self.func, self.name, calc_dtype, res_dtype,
+                          w_obj, out)
 
 
 class W_Ufunc2(W_Ufunc):
@@ -289,11 +273,15 @@
                          int_only)
         self.func = func
         self.comparison_func = comparison_func
+        if name == 'logical_and':
+            self.done_func = done_if_false
+        elif name == 'logical_or':
+            self.done_func = done_if_true
+        else:
+            self.done_func = None
 
     @jit.unroll_safe
     def call(self, space, args_w):
-        from pypy.module.micronumpy.interp_numarray import (Call2,
-            convert_to_array, Scalar, shape_agreement, BaseArray)
         if len(args_w) > 2:
             [w_lhs, w_rhs, w_out] = args_w
         else:
@@ -304,50 +292,38 @@
         if space.is_w(w_out, space.w_None) or w_out is None:
             out = None
             calc_dtype = find_binop_result_dtype(space,
-                w_lhs.find_dtype(), w_rhs.find_dtype(),
+                w_lhs.get_dtype(), w_rhs.get_dtype(),
                 int_only=self.int_only,
                 promote_to_float=self.promote_to_float,
                 promote_bools=self.promote_bools,
             )
-        elif not isinstance(w_out, BaseArray):
+        elif not isinstance(w_out, W_NDimArray):
             raise OperationError(space.w_TypeError, space.wrap(
                     'output must be an array'))
         else:
             out = w_out
-            calc_dtype = out.find_dtype()
+            calc_dtype = out.get_dtype()
         if self.comparison_func:
             res_dtype = interp_dtype.get_dtype_cache(space).w_booldtype
         else:
             res_dtype = calc_dtype
-        if isinstance(w_lhs, Scalar) and isinstance(w_rhs, Scalar):
+        if w_lhs.is_scalar() and w_rhs.is_scalar():
             arr = self.func(calc_dtype,
-                w_lhs.value.convert_to(calc_dtype),
-                w_rhs.value.convert_to(calc_dtype)
+                w_lhs.get_scalar_value().convert_to(calc_dtype),
+                w_rhs.get_scalar_value().convert_to(calc_dtype)
             )
-            if isinstance(out,Scalar):
-                out.value = arr
-            elif isinstance(out, BaseArray):
-                out.fill(space, arr)
+            if isinstance(out, W_NDimArray):
+                if out.is_scalar():
+                    out.set_scalar_value(arr)
+                else:
+                    out.fill(arr)
             else:
                 out = arr
-            return space.wrap(out)
-        new_shape = shape_agreement(space, w_lhs.shape, w_rhs.shape)
-        # Test correctness of out.shape
-        if out and out.shape != shape_agreement(space, new_shape, out.shape):
-            raise operationerrfmt(space.w_ValueError,
-                'output parameter shape mismatch, could not broadcast [%s]' +
-                ' to [%s]',
-                ",".join([str(x) for x in new_shape]),
-                ",".join([str(x) for x in out.shape]),
-                )
-        w_res = Call2(self.func, self.name,
-                      new_shape, calc_dtype,
-                      res_dtype, w_lhs, w_rhs, out)
-        w_lhs.add_invalidates(space, w_res)
-        w_rhs.add_invalidates(space, w_res)
-        if out:
-            w_res.get_concrete()
-        return w_res
+            return out
+        new_shape = shape_agreement(space, w_lhs.get_shape(), w_rhs)
+        new_shape = shape_agreement(space, new_shape, out, broadcast_down=False)
+        return loop.call2(new_shape, self.func, self.name, calc_dtype,
+                          res_dtype, w_lhs, w_rhs, out)
 
 
 W_Ufunc.typedef = TypeDef("ufunc",
diff --git a/pypy/module/micronumpy/iter.py b/pypy/module/micronumpy/iter.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/micronumpy/iter.py
@@ -0,0 +1,123 @@
+
+""" This is a mini-tutorial on iterators, strides, and
+memory layout. It assumes you are familiar with the terms, see
+http://docs.scipy.org/doc/numpy/reference/arrays.ndarray.html
+for a more gentle introduction.
+
+Given an array x: x.shape == [5,6],
+
+At which byte in x.data does the item x[3,4] begin?
+if x.strides==[1,5]:
+    pData = x.pData + (x.start + 3*1 + 4*5)*sizeof(x.pData[0])
+    pData = x.pData + (x.start + 24) * sizeof(x.pData[0])
+so the offset of the element is 24 elements after the first
+
+What is the next element in x after coordinates [3,4]?
+if x.order =='C':
+   next == [3,5] => offset is 28
+if x.order =='F':
+   next == [4,4] => offset is 24
+so for the strides [1,5] x is 'F' contiguous
+likewise, for the strides [6,1] x would be 'C' contiguous.
+
+Iterators have an internal representation of the current coordinates
+(indices), the array, strides, and backstrides. A short digression to
+explain backstrides: what is the coordinate and offset after [3,5] in
+the example above?
+if x.order == 'C':
+   next == [4,0] => offset is 4
+if x.order == 'F':
+   next == [4,5] => offset is 25
+Note that in 'C' order we stepped BACKWARDS 24 while 'overflowing' a
+shape dimension
+  which is back 25 and forward 1,
+  which is x.strides[1] * (x.shape[1] - 1) + x.strides[0]
+so if we precalculate the overflow backstride as 
+[x.strides[i] * (x.shape[i] - 1) for i in range(len(x.shape))]
+we can go faster.
+All the calculations happen in next()
+
+next_skip_x() tries to do the iteration for a number of steps at once,
+but then we cannot gaurentee that we only overflow one single shape 
+dimension, perhaps we could overflow times in one big step.
+"""
+
+from pypy.module.micronumpy.strides import enumerate_chunks,\
+     calculate_slice_strides
+from pypy.module.micronumpy.base import W_NDimArray
+from pypy.rlib import jit
+
+# structures to describe slicing
+
+class BaseChunk(object):
+    pass
+
+class RecordChunk(BaseChunk):
+    def __init__(self, name):
+        self.name = name
+
+    def apply(self, arr):
+        ofs, subdtype = arr.dtype.fields[self.name]
+        # strides backstrides are identical, ofs only changes start
+        return W_NDimArray.new_slice(arr.start + ofs, arr.strides,
+                                     arr.backstrides,
+                                     arr.shape, arr, subdtype)
+
+class Chunks(BaseChunk):
+    def __init__(self, l):
+        self.l = l
+
+    @jit.unroll_safe
+    def extend_shape(self, old_shape):
+        shape = []
+        i = -1
+        for i, c in enumerate_chunks(self.l):
+            if c.step != 0:
+                shape.append(c.lgt)
+        s = i + 1
+        assert s >= 0
+        return shape[:] + old_shape[s:]
+
+    def apply(self, arr):
+        shape = self.extend_shape(arr.shape)
+        r = calculate_slice_strides(arr.shape, arr.start, arr.strides,
+                                    arr.backstrides, self.l)
+        _, start, strides, backstrides = r
+        return W_NDimArray.new_slice(start, strides[:], backstrides[:],
+                                     shape[:], arr)
+
+
+class Chunk(BaseChunk):
+    axis_step = 1
+
+    def __init__(self, start, stop, step, lgt):
+        self.start = start
+        self.stop = stop
+        self.step = step
+        self.lgt = lgt
+
+    def __repr__(self):
+        return 'Chunk(%d, %d, %d, %d)' % (self.start, self.stop, self.step,
+                                          self.lgt)
+
+class NewAxisChunk(Chunk):
+    start = 0
+    stop = 1
+    step = 1
+    lgt = 1
+    axis_step = 0
+
+    def __init__(self):
+        pass
+
+class BaseTransform(object):
+    pass
+
+class ViewTransform(BaseTransform):
+    def __init__(self, chunks):
+        # 4-tuple specifying slicing
+        self.chunks = chunks
+
+class BroadcastTransform(BaseTransform):
+    def __init__(self, res_shape):
+        self.res_shape = res_shape
diff --git a/pypy/module/micronumpy/loop.py b/pypy/module/micronumpy/loop.py
--- a/pypy/module/micronumpy/loop.py
+++ b/pypy/module/micronumpy/loop.py
@@ -3,81 +3,244 @@
 signatures
 """
 
-from pypy.rlib.jit import JitDriver, hint, unroll_safe, promote
-from pypy.module.micronumpy.interp_iter import ConstantIterator
+from pypy.rlib.objectmodel import specialize
+from pypy.module.micronumpy.base import W_NDimArray
+from pypy.rlib.rstring import StringBuilder
+from pypy.rpython.lltypesystem import lltype, rffi
 
-class NumpyEvalFrame(object):
-    _virtualizable2_ = ['iterators[*]', 'final_iter', 'arraylist[*]',
-                        'value', 'identity', 'cur_value']
+def call2(shape, func, name, calc_dtype, res_dtype, w_lhs, w_rhs, out):
+    if out is None:
+        out = W_NDimArray.from_shape(shape, res_dtype)
+    left_iter = w_lhs.create_iter(shape)
+    right_iter = w_rhs.create_iter(shape)
+    out_iter = out.create_iter(shape)
+    while not out_iter.done():
+        w_left = left_iter.getitem().convert_to(calc_dtype)
+        w_right = right_iter.getitem().convert_to(calc_dtype)
+        out_iter.setitem(func(calc_dtype, w_left, w_right).convert_to(
+            res_dtype))
+        left_iter.next()
+        right_iter.next()
+        out_iter.next()
+    return out
 
-    @unroll_safe
-    def __init__(self, iterators, arrays):
-        self = hint(self, access_directly=True, fresh_virtualizable=True)
-        self.iterators = iterators[:]
-        self.arrays = arrays[:]
-        for i in range(len(self.iterators)):
-            iter = self.iterators[i]
-            if not isinstance(iter, ConstantIterator):
-                self.final_iter = i
-                break
+def call1(shape, func, name, calc_dtype, res_dtype, w_obj, out):
+    if out is None:
+        out = W_NDimArray.from_shape(shape, res_dtype)
+    obj_iter = w_obj.create_iter(shape)
+    out_iter = out.create_iter(shape)
+    while not out_iter.done():
+        elem = obj_iter.getitem().convert_to(calc_dtype)
+        out_iter.setitem(func(calc_dtype, elem).convert_to(res_dtype))
+        out_iter.next()
+        obj_iter.next()
+    return out
+
+def setslice(shape, target, source):
+    # note that unlike everything else, target and source here are
+    # array implementations, not arrays
+    target_iter = target.create_iter(shape)
+    source_iter = source.create_iter(shape)
+    dtype = target.dtype
+    while not target_iter.done():
+        target_iter.setitem(source_iter.getitem().convert_to(dtype))
+        target_iter.next()
+        source_iter.next()
+    return target
+
+def compute_reduce(obj, calc_dtype, func, done_func, identity):
+    obj_iter = obj.create_iter(obj.get_shape())
+    if identity is None:
+        cur_value = obj_iter.getitem().convert_to(calc_dtype)
+        obj_iter.next()
+    else:
+        cur_value = identity.convert_to(calc_dtype)
+    while not obj_iter.done():
+        rval = obj_iter.getitem().convert_to(calc_dtype)
+        if done_func is not None and done_func(calc_dtype, rval):
+            return rval
+        cur_value = func(calc_dtype, cur_value, rval)
+        obj_iter.next()
+    return cur_value
+
+def fill(arr, box):
+    arr_iter = arr.create_iter(arr.get_shape())
+    while not arr_iter.done():
+        arr_iter.setitem(box)
+        arr_iter.next()
+
+def where(out, shape, arr, x, y, dtype):
+    out_iter = out.create_iter(shape)
+    arr_iter = arr.create_iter(shape)
+    arr_dtype = arr.get_dtype()
+    x_iter = x.create_iter(shape)
+    y_iter = y.create_iter(shape)
+    if x.is_scalar():
+        if y.is_scalar():
+            iter = arr_iter
         else:
-            self.final_iter = -1
-        self.cur_value = None
-        self.identity = None
+            iter = y_iter
+    else:
+        iter = x_iter
+    while not iter.done():
+        w_cond = arr_iter.getitem()
+        if arr_dtype.itemtype.bool(w_cond):
+            w_val = x_iter.getitem().convert_to(dtype)
+        else:
+            w_val = y_iter.getitem().convert_to(dtype)
+        out_iter.setitem(w_val)
+        out_iter.next()
+        arr_iter.next()
+        x_iter.next()
+        y_iter.next()
+    return out
 
-    def done(self):
-        final_iter = promote(self.final_iter)
-        if final_iter < 0:
-            assert False
-        return self.iterators[final_iter].done()
+def do_axis_reduce(shape, func, arr, dtype, axis, out, identity):
+    out_iter = out.create_axis_iter(arr.get_shape(), axis)
+    arr_iter = arr.create_iter(arr.get_shape())
+    if identity is not None:
+        identity = identity.convert_to(dtype)
+    while not out_iter.done():
+        w_val = arr_iter.getitem().convert_to(dtype)
+        if out_iter.first_line:
+            if identity is not None:
+                w_val = func(dtype, identity, w_val)
+        else:
+            cur = out_iter.getitem()
+            w_val = func(dtype, cur, w_val)
+        out_iter.setitem(w_val)
+        arr_iter.next()
+        out_iter.next()
+    return out
 
-    @unroll_safe
-    def next(self, shapelen):
-        for i in range(len(self.iterators)):
-            self.iterators[i] = self.iterators[i].next(shapelen)
+ at specialize.arg(0)
+def argmin_argmax(op_name, arr):
+    result = 0
+    idx = 1
+    dtype = arr.get_dtype()
+    iter = arr.create_iter(arr.get_shape())
+    cur_best = iter.getitem()
+    iter.next()
+    while not iter.done():
+        w_val = iter.getitem()
+        new_best = getattr(dtype.itemtype, op_name)(cur_best, w_val)
+        if dtype.itemtype.ne(new_best, cur_best):
+            result = idx
+            cur_best = new_best
+        iter.next()
+        idx += 1
+    return result
 
-    @unroll_safe
-    def next_from_second(self, shapelen):
-        """ Don't increase the first iterator
-        """
-        for i in range(1, len(self.iterators)):
-            self.iterators[i] = self.iterators[i].next(shapelen)
+def multidim_dot(space, left, right, result, dtype, right_critical_dim):
+    ''' assumes left, right are concrete arrays
+    given left.shape == [3, 5, 7],
+          right.shape == [2, 7, 4]
+    then
+     result.shape == [3, 5, 2, 4]
+     broadcast shape should be [3, 5, 2, 7, 4]
+     result should skip dims 3 which is len(result_shape) - 1
+        (note that if right is 1d, result should 
+                  skip len(result_shape))
+     left should skip 2, 4 which is a.ndims-1 + range(right.ndims)
+          except where it==(right.ndims-2)
+     right should skip 0, 1
+    '''
+    left_shape = left.get_shape()
+    right_shape = right.get_shape()
+    broadcast_shape = left_shape[:-1] + right_shape
+    left_skip = [len(left_shape) - 1 + i for i in range(len(right_shape))
+                                         if i != right_critical_dim]
+    right_skip = range(len(left_shape) - 1)
+    result_skip = [len(result.get_shape()) - (len(right_shape) > 1)]
+    outi = result.create_dot_iter(broadcast_shape, result_skip)
+    lefti = left.create_dot_iter(broadcast_shape, left_skip)
+    righti = right.create_dot_iter(broadcast_shape, right_skip)
+    while not outi.done():
+        lval = lefti.getitem().convert_to(dtype) 
+        rval = righti.getitem().convert_to(dtype) 
+        outval = outi.getitem().convert_to(dtype) 
+        v = dtype.itemtype.mul(lval, rval)
+        value = dtype.itemtype.add(v, outval).convert_to(dtype)
+        outi.setitem(value)
+        outi.next()
+        righti.next()
+        lefti.next()
+    return result
 
-    def next_first(self, shapelen):
-        self.iterators[0] = self.iterators[0].next(shapelen)
+def count_all_true(arr):
+    s = 0
+    if arr.is_scalar():
+        return arr.get_dtype().itemtype.bool(arr.get_scalar_value())
+    iter = arr.create_iter()
+    while not iter.done():
+        s += iter.getitem_bool()
+        iter.next()
+    return s
 
-    def get_final_iter(self):
-        final_iter = promote(self.final_iter)
-        if final_iter < 0:
-            assert False
-        return self.iterators[final_iter]
+def getitem_filter(res, arr, index):
+    res_iter = res.create_iter()
+    index_iter = index.create_iter()
+    arr_iter = arr.create_iter()
+    while not index_iter.done():
+        if index_iter.getitem_bool():
+            res_iter.setitem(arr_iter.getitem())
+            res_iter.next()
+        index_iter.next()
+        arr_iter.next()
+    return res
 
-def get_printable_location(shapelen, sig):
-    return 'numpy ' + sig.debug_repr() + ' [%d dims]' % (shapelen,)
+def setitem_filter(arr, index, value):
+    arr_iter = arr.create_iter()
+    index_iter = index.create_iter()
+    value_iter = value.create_iter()
+    while not arr_iter.done():
+        if index_iter.getitem_bool():
+            arr_iter.setitem(value_iter.getitem())
+            value_iter.next()
+        arr_iter.next()
+        index_iter.next()
 
-numpy_driver = JitDriver(
-    greens=['shapelen', 'sig'],
-    virtualizables=['frame'],
-    reds=['frame', 'arr'],
-    get_printable_location=get_printable_location,
-    name='numpy',
-)
+def flatiter_getitem(res, base_iter, step):
+    ri = res.create_iter()
+    while not ri.done():
+        ri.setitem(base_iter.getitem())
+        base_iter.next_skip_x(step)
+        ri.next()
+    return res
 
-class ComputationDone(Exception):
-    def __init__(self, value):
-        self.value = value
+def flatiter_setitem(arr, val, start, step, length):
+    dtype = arr.get_dtype()
+    arr_iter = arr.create_iter()
+    val_iter = val.create_iter()
+    arr_iter.next_skip_x(start)
+    while length > 0:
+        arr_iter.setitem(val_iter.getitem().convert_to(dtype))
+        # need to repeat i_nput values until all assignments are done
+        arr_iter.next_skip_x(step)
+        length -= 1
+        val_iter.next()
+        # WTF numpy?
+        val_iter.reset()
 
-def compute(arr):
-    sig = arr.find_sig()
-    shapelen = len(arr.shape)
-    frame = sig.create_frame(arr)
-    try:
-        while not frame.done():
-            numpy_driver.jit_merge_point(sig=sig,
-                                         shapelen=shapelen,
-                                         frame=frame, arr=arr)
-            sig.eval(frame, arr)
-            frame.next(shapelen)
-        return frame.cur_value
-    except ComputationDone, e:
-        return e.value
+def fromstring_loop(a, dtype, itemsize, s):
+    i = 0
+    ai = a.create_iter()
+    while not ai.done():
+        val = dtype.itemtype.runpack_str(s[i*itemsize:i*itemsize + itemsize])
+        ai.setitem(val)
+        ai.next()
+        i += 1
+
+def tostring(space, arr):
+    builder = StringBuilder()
+    iter = arr.create_iter()
+    res_str = W_NDimArray.from_shape([1], arr.get_dtype(), order='C')
+    itemsize = arr.get_dtype().itemtype.get_element_size()
+    res_str_casted = rffi.cast(rffi.CArrayPtr(lltype.Char),
+                               res_str.implementation.get_storage_as_int(space))
+    while not iter.done():
+        res_str.implementation.setitem(0, iter.getitem())
+        for i in range(itemsize):
+            builder.append(res_str_casted[i])
+        iter.next()
+    return builder.build()
diff --git a/pypy/module/micronumpy/signature.py b/pypy/module/micronumpy/signature.py
deleted file mode 100644
--- a/pypy/module/micronumpy/signature.py
+++ /dev/null
@@ -1,564 +0,0 @@
-from pypy.rlib.objectmodel import r_dict, compute_identity_hash, compute_hash
-from pypy.rlib.rarithmetic import intmask
-from pypy.module.micronumpy.interp_iter import ConstantIterator, AxisIterator,\
-     ViewTransform, BroadcastTransform
-from pypy.tool.pairtype import extendabletype
-from pypy.module.micronumpy.loop import ComputationDone
-from pypy.rlib import jit
-
-""" Signature specifies both the numpy expression that has been constructed
-and the assembler to be compiled. This is a very important observation -
-Two expressions will be using the same assembler if and only if they are
-compiled to the same signature.
-
-This is also a very convinient tool for specializations. For example
-a + a and a + b (where a != b) will compile to different assembler because
-we specialize on the same array access.
-
-When evaluating, signatures will create iterators per signature node,
-potentially sharing some of them. Iterators depend also on the actual
-expression, they're not only dependant on the array itself. For example
-a + b where a is dim 2 and b is dim 1 would create a broadcasted iterator for
-the array b.
-
-Such iterator changes are called Transformations. An actual iterator would
-be a combination of array and various transformation, like view, broadcast,
-dimension swapping etc.
-
-See interp_iter for transformations
-"""
-
-def new_printable_location(driver_name):
-    def get_printable_location(shapelen, sig):
-        return 'numpy ' + sig.debug_repr() + ' [%d dims,%s]' % (shapelen, driver_name)
-    return get_printable_location
-
-def sigeq(one, two):
-    return one.eq(two)
-
-def sigeq_no_numbering(one, two):
-    """ Cache for iterator numbering should not compare array numbers
-    """
-    return one.eq(two, compare_array_no=False)
-
-def sighash(sig):
-    return sig.hash()
-
-known_sigs = r_dict(sigeq, sighash)
-
-def find_sig(sig, arr):
-    sig.invent_array_numbering(arr)
-    try:
-        return known_sigs[sig]
-    except KeyError:
-        sig.invent_numbering()
-        known_sigs[sig] = sig
-        return sig
-
-def _add_ptr_to_cache(ptr, cache):
-    i = 0
-    for p in cache:
-        if ptr == p:
-            return i
-        i += 1
-    else:
-        res = len(cache)
-        cache.append(ptr)
-        return res
-
-def new_cache():
-    return r_dict(sigeq_no_numbering, sighash)
-
-class Signature(object):
-    __metaclass_ = extendabletype
-    
-    _attrs_ = ['iter_no', 'array_no']
-    _immutable_fields_ = ['iter_no', 'array_no']
-
-    array_no = 0
-    iter_no = 0
-
-    def invent_numbering(self):
-        cache = new_cache()
-        allnumbers = []
-        self._invent_numbering(cache, allnumbers)
-
-    def invent_array_numbering(self, arr):
-        cache = []
-        self._invent_array_numbering(arr, cache)
-
-    def _invent_numbering(self, cache, allnumbers):
-        try:
-            no = cache[self]
-        except KeyError:
-            no = len(allnumbers)
-            cache[self] = no
-            allnumbers.append(no)
-        self.iter_no = no
-
-    def create_frame(self, arr):
-        from pypy.module.micronumpy.loop import NumpyEvalFrame
-        
-        iterlist = []
-        arraylist = []
-        self._create_iter(iterlist, arraylist, arr, [])
-        f = NumpyEvalFrame(iterlist, arraylist)
-        # hook for cur_value being used by reduce
-        arr.compute_first_step(self, f)
-        return f
-
-    def debug_repr(self):
-        # should be overridden, but in case it isn't, provide a default
-        return str(self)
-
-class ConcreteSignature(Signature):
-    _immutable_fields_ = ['dtype']
-
-    def __init__(self, dtype):
-        self.dtype = dtype
-
-    def eq(self, other, compare_array_no=True):
-        if type(self) is not type(other):
-            return False
-        assert isinstance(other, ConcreteSignature)
-        if compare_array_no:
-            if self.array_no != other.array_no:
-                return False
-        return self.dtype is other.dtype
-
-    def hash(self):
-        return compute_identity_hash(self.dtype)
-
-class ArraySignature(ConcreteSignature):
-    def debug_repr(self):
-        return 'Array'
-
-    def _invent_array_numbering(self, arr, cache):
-        from pypy.module.micronumpy.interp_numarray import ConcreteArray
-        concr = arr.get_concrete()
-        # this get_concrete never forces assembler. If we're here and array
-        # is not of a concrete class it means that we have a _forced_result,
-        # otherwise the signature would not match
-        assert isinstance(concr, ConcreteArray)
-        assert concr.dtype is self.dtype
-        self.array_no = _add_ptr_to_cache(concr.storage, cache)
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import ConcreteArray
-        concr = arr.get_concrete()
-        assert isinstance(concr, ConcreteArray)
-        if self.iter_no >= len(iterlist):
-            iterlist.append(concr.create_iter(transforms))
-        if self.array_no >= len(arraylist):
-            arraylist.append(concr)
-
-    def eval(self, frame, arr):
-        iter = frame.iterators[self.iter_no]
-        return self.dtype.getitem(frame.arrays[self.array_no], iter.offset)
-
-class ScalarSignature(ConcreteSignature):
-    def debug_repr(self):
-        return 'Scalar'
-
-    def _invent_array_numbering(self, arr, cache):
-        pass
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        if self.iter_no >= len(iterlist):
-            iter = ConstantIterator()
-            iterlist.append(iter)
-
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import Scalar
-        assert isinstance(arr, Scalar)
-        return arr.value
-
-class ViewSignature(ArraySignature):
-    def debug_repr(self):
-        return 'Slice'
-
-    def _invent_numbering(self, cache, allnumbers):
-        # always invent a new number for view
-        no = len(allnumbers)
-        allnumbers.append(no)
-        self.iter_no = no
-
-class FlatSignature(ViewSignature):
-    def debug_repr(self):
-        return 'Flat'
-
-class VirtualSliceSignature(Signature):
-    def __init__(self, child):
-        self.child = child
-
-    def _invent_array_numbering(self, arr, cache):
-        from pypy.module.micronumpy.interp_numarray import VirtualSlice
-        assert isinstance(arr, VirtualSlice)
-        self.child._invent_array_numbering(arr.child, cache)
-
-    def _invent_numbering(self, cache, allnumbers):
-        self.child._invent_numbering(new_cache(), allnumbers)
-
-    def hash(self):
-        return intmask(self.child.hash() ^ 1234)
-
-    def eq(self, other, compare_array_no=True):
-        if type(self) is not type(other):
-            return False
-        assert isinstance(other, VirtualSliceSignature)
-        return self.child.eq(other.child, compare_array_no)
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import VirtualSlice
-        assert isinstance(arr, VirtualSlice)
-        transforms = [ViewTransform(arr.chunks)] + transforms 
-        self.child._create_iter(iterlist, arraylist, arr.child, transforms)
-
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import VirtualSlice
-        assert isinstance(arr, VirtualSlice)
-        return self.child.eval(frame, arr.child)
-
-    def debug_repr(self):
-        return 'VirtualSlice(%s)' % self.child.debug_repr()
-
-class Call1(Signature):
-    _immutable_fields_ = ['unfunc', 'name', 'child', 'res', 'dtype']
-
-    def __init__(self, func, name, dtype, child, res=None):
-        self.unfunc = func
-        self.child = child
-        self.name = name
-        self.dtype = dtype
-        self.res  = res
-
-    def hash(self):
-        return compute_hash(self.name) ^ intmask(self.child.hash() << 1)
-
-    def eq(self, other, compare_array_no=True):
-        if type(self) is not type(other):
-            return False
-        assert isinstance(other, Call1)
-        return (self.unfunc is other.unfunc and
-                self.child.eq(other.child, compare_array_no))
-
-    def debug_repr(self):
-        return 'Call1(%s, %s)' % (self.name, self.child.debug_repr())
-
-    def _invent_numbering(self, cache, allnumbers):
-        self.child._invent_numbering(cache, allnumbers)
-
-    def _invent_array_numbering(self, arr, cache):
-        from pypy.module.micronumpy.interp_numarray import Call1
-        assert isinstance(arr, Call1)
-        self.child._invent_array_numbering(arr.values, cache)
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import Call1
-        assert isinstance(arr, Call1)
-        self.child._create_iter(iterlist, arraylist, arr.values, transforms)
-
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import Call1
-        assert isinstance(arr, Call1)
-        v = self.child.eval(frame, arr.values).convert_to(arr.calc_dtype)
-        return self.unfunc(arr.calc_dtype, v)
-
-
-class BroadcastUfunc(Call1):
-    def _invent_numbering(self, cache, allnumbers):
-        self.res._invent_numbering(cache, allnumbers)
-        self.child._invent_numbering(new_cache(), allnumbers)
-
-    def debug_repr(self):
-        return 'BroadcastUfunc(%s, %s)' % (self.name, self.child.debug_repr())
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import Call1
-
-        assert isinstance(arr, Call1)
-        vtransforms = [BroadcastTransform(arr.values.shape)] + transforms
-        self.child._create_iter(iterlist, arraylist, arr.values, vtransforms)
-        self.res._create_iter(iterlist, arraylist, arr.res, transforms)
-
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import Call1
-        assert isinstance(arr, Call1)
-        v = self.child.eval(frame, arr.values).convert_to(arr.calc_dtype)
-        return self.unfunc(arr.calc_dtype, v)
-
-class Call2(Signature):
-    _immutable_fields_ = ['binfunc', 'name', 'calc_dtype', 'left', 'right']
-
-    def __init__(self, func, name, calc_dtype, left, right):
-        self.binfunc = func
-        self.left = left
-        self.right = right
-        self.name = name
-        self.calc_dtype = calc_dtype
-
-    def hash(self):
-        return (compute_hash(self.name) ^ intmask(self.left.hash() << 1) ^
-                intmask(self.right.hash() << 2))
-
-    def eq(self, other, compare_array_no=True):
-        if type(self) is not type(other):
-            return False
-        assert isinstance(other, Call2)
-        return (self.binfunc is other.binfunc and
-                self.calc_dtype is other.calc_dtype and
-                self.left.eq(other.left, compare_array_no) and
-                self.right.eq(other.right, compare_array_no))
-
-    def _invent_array_numbering(self, arr, cache):
-        from pypy.module.micronumpy.interp_numarray import Call2
-        assert isinstance(arr, Call2)
-        self.left._invent_array_numbering(arr.left, cache)
-        self.right._invent_array_numbering(arr.right, cache)
-
-    def _invent_numbering(self, cache, allnumbers):
-        self.left._invent_numbering(cache, allnumbers)
-        self.right._invent_numbering(cache, allnumbers)
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import Call2
-
-        assert isinstance(arr, Call2)
-        self.left._create_iter(iterlist, arraylist, arr.left, transforms)
-        self.right._create_iter(iterlist, arraylist, arr.right, transforms)
-
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import Call2
-        assert isinstance(arr, Call2)
-        lhs = self.left.eval(frame, arr.left).convert_to(self.calc_dtype)
-        rhs = self.right.eval(frame, arr.right).convert_to(self.calc_dtype)
-        return self.binfunc(self.calc_dtype, lhs, rhs)
-
-    def debug_repr(self):
-        return 'Call2(%s, %s, %s)' % (self.name, self.left.debug_repr(),
-                                      self.right.debug_repr())
-
-class ResultSignature(Call2):
-    def __init__(self, dtype, left, right):
-        Call2.__init__(self, None, 'assign', dtype, left, right)
-
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import ResultArray
-
-        assert isinstance(arr, ResultArray)
-        offset = frame.get_final_iter().offset
-        val = self.right.eval(frame, arr.right)
-        arr.left.setitem(offset, val)
-
-class BroadcastResultSignature(ResultSignature):
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import ResultArray
-
-        assert isinstance(arr, ResultArray)
-        rtransforms = [BroadcastTransform(arr.left.shape)] + transforms
-        self.left._create_iter(iterlist, arraylist, arr.left, transforms)
-        self.right._create_iter(iterlist, arraylist, arr.right, rtransforms)
-
-class ToStringSignature(Call1):
-    def __init__(self, dtype, child):
-        Call1.__init__(self, None, 'tostring', dtype, child)
-
-    @jit.unroll_safe
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import ToStringArray
-
-        assert isinstance(arr, ToStringArray)
-        arr.res_str.setitem(0, self.child.eval(frame, arr.values).convert_to(
-            self.dtype))
-        for i in range(arr.item_size):
-            arr.s.append(arr.res_str_casted[i])
-
-class BroadcastLeft(Call2):
-    def _invent_numbering(self, cache, allnumbers):
-        self.left._invent_numbering(new_cache(), allnumbers)
-        self.right._invent_numbering(cache, allnumbers)
-    
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import Call2
-
-        assert isinstance(arr, Call2)
-        ltransforms = [BroadcastTransform(arr.shape)] + transforms
-        self.left._create_iter(iterlist, arraylist, arr.left, ltransforms)
-        self.right._create_iter(iterlist, arraylist, arr.right, transforms)
-
-class BroadcastRight(Call2):
-    def _invent_numbering(self, cache, allnumbers):
-        self.left._invent_numbering(cache, allnumbers)
-        self.right._invent_numbering(new_cache(), allnumbers)
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import Call2
-
-        assert isinstance(arr, Call2)
-        rtransforms = [BroadcastTransform(arr.shape)] + transforms
-        self.left._create_iter(iterlist, arraylist, arr.left, transforms)
-        self.right._create_iter(iterlist, arraylist, arr.right, rtransforms)
-
-class BroadcastBoth(Call2):
-    def _invent_numbering(self, cache, allnumbers):
-        self.left._invent_numbering(new_cache(), allnumbers)
-        self.right._invent_numbering(new_cache(), allnumbers)
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import Call2
-
-        assert isinstance(arr, Call2)
-        rtransforms = [BroadcastTransform(arr.shape)] + transforms
-        ltransforms = [BroadcastTransform(arr.shape)] + transforms
-        self.left._create_iter(iterlist, arraylist, arr.left, ltransforms)
-        self.right._create_iter(iterlist, arraylist, arr.right, rtransforms)
-
-class ReduceSignature(Call2):
-    _immutable_fields_ = ['binfunc', 'name', 'calc_dtype',
-                          'left', 'right', 'done_func']
-    
-    def __init__(self, func, name, calc_dtype, left, right,
-                 done_func):
-        Call2.__init__(self, func, name, calc_dtype, left, right)
-        self.done_func = done_func
-        
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import ReduceArray
-        assert isinstance(arr, ReduceArray)
-        rval = self.right.eval(frame, arr.right).convert_to(self.calc_dtype)
-        if self.done_func is not None and self.done_func(self.calc_dtype, rval):
-            raise ComputationDone(rval)
-        frame.cur_value = self.binfunc(self.calc_dtype, frame.cur_value, rval)
-
-    def debug_repr(self):
-        return 'ReduceSig(%s, %s)' % (self.name, self.right.debug_repr())
-
-class SliceloopSignature(Call2):
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import Call2
-        
-        assert isinstance(arr, Call2)
-        ofs = frame.iterators[0].offset
-        arr.left.setitem(ofs, self.right.eval(frame, arr.right).convert_to(
-            self.calc_dtype))
-
-    def _invent_numbering(self, cache, allnumbers):
-        self.left._invent_numbering(new_cache(), allnumbers)
-        self.right._invent_numbering(cache, allnumbers)
-
-    def debug_repr(self):
-        return 'SliceLoop(%s, %s, %s)' % (self.name, self.left.debug_repr(),
-                                          self.right.debug_repr())
-
-class SliceloopBroadcastSignature(SliceloopSignature):
-    def _invent_numbering(self, cache, allnumbers):
-        self.left._invent_numbering(new_cache(), allnumbers)
-        self.right._invent_numbering(cache, allnumbers)
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import SliceArray
-
-        assert isinstance(arr, SliceArray)
-        rtransforms = [BroadcastTransform(arr.shape)] + transforms
-        self.left._create_iter(iterlist, arraylist, arr.left, transforms)
-        self.right._create_iter(iterlist, arraylist, arr.right, rtransforms)
-
-class AxisReduceSignature(Call2):
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_numarray import AxisReduce,\
-             ConcreteArray
-
-        assert isinstance(arr, AxisReduce)
-        left = arr.left
-        assert isinstance(left, ConcreteArray)
-        iterlist.append(AxisIterator(left.start, arr.dim, arr.shape,
-                                     left.strides, left.backstrides))
-        self.right._create_iter(iterlist, arraylist, arr.right, transforms)
-
-    def _invent_numbering(self, cache, allnumbers):
-        allnumbers.append(0)
-        self.right._invent_numbering(cache, allnumbers)
-
-    def _invent_array_numbering(self, arr, cache):
-        from pypy.module.micronumpy.interp_numarray import AxisReduce
-
-        assert isinstance(arr, AxisReduce)
-        self.right._invent_array_numbering(arr.right, cache)
-
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_numarray import AxisReduce
-
-        assert isinstance(arr, AxisReduce)
-        iterator = frame.get_final_iter()
-        v = self.right.eval(frame, arr.right).convert_to(self.calc_dtype)
-        if iterator.first_line:
-            if frame.identity is not None:
-                value = self.binfunc(self.calc_dtype, frame.identity, v)
-            else:
-                value = v
-        else:
-            cur = arr.left.getitem(iterator.offset)
-            value = self.binfunc(self.calc_dtype, cur, v)
-        arr.left.setitem(iterator.offset, value)
-    def debug_repr(self):
-        return 'AxisReduceSig(%s, %s)' % (self.name, self.right.debug_repr())
-
-class WhereSignature(Signature):
-    _immutable_fields_ = ['dtype', 'arrdtype', 'arrsig', 'xsig', 'ysig']
-    
-    def __init__(self, dtype, arrdtype, arrsig, xsig, ysig):
-        self.dtype = dtype
-        self.arrdtype = arrdtype
-        self.arrsig = arrsig
-        self.xsig = xsig
-        self.ysig = ysig
-
-    def hash(self):
-        return (intmask(self.arrsig.hash() << 1) ^
-                intmask(self.xsig.hash() << 2) ^
-                intmask(self.ysig.hash() << 3))
-
-    def eq(self, other, compare_array_no=True):
-        if type(self) is not type(other):
-            return False
-        assert isinstance(other, WhereSignature)
-        return (self.arrsig.eq(other.arrsig, compare_array_no) and
-                self.xsig.eq(other.xsig, compare_array_no) and
-                self.ysig.eq(other.ysig, compare_array_no))
-
-    def _invent_array_numbering(self, arr, cache):
-        from pypy.module.micronumpy.interp_arrayops import WhereArray
-        assert isinstance(arr, WhereArray)
-        self.arrsig._invent_array_numbering(arr.arr, cache)
-        self.xsig._invent_array_numbering(arr.x, cache)
-        self.ysig._invent_array_numbering(arr.y, cache)
-
-    def _invent_numbering(self, cache, allnumbers):
-        self.arrsig._invent_numbering(cache, allnumbers)
-        self.xsig._invent_numbering(cache, allnumbers)
-        self.ysig._invent_numbering(cache, allnumbers)
-
-    def _create_iter(self, iterlist, arraylist, arr, transforms):
-        from pypy.module.micronumpy.interp_arrayops import WhereArray
-
-        assert isinstance(arr, WhereArray)
-        # XXX this does not support broadcasting correctly
-        self.arrsig._create_iter(iterlist, arraylist, arr.arr, transforms)
-        self.xsig._create_iter(iterlist, arraylist, arr.x, transforms)
-        self.ysig._create_iter(iterlist, arraylist, arr.y, transforms)
- 
-    def eval(self, frame, arr):
-        from pypy.module.micronumpy.interp_arrayops import WhereArray
-        assert isinstance(arr, WhereArray)
-        lhs = self.xsig.eval(frame, arr.x).convert_to(self.dtype)
-        rhs = self.ysig.eval(frame, arr.y).convert_to(self.dtype)
-        w_val = self.arrsig.eval(frame, arr.arr)
-        if self.arrdtype.itemtype.bool(w_val):
-            return lhs
-        else:
-            return rhs
-
-    def debug_repr(self):
-        return 'Where(%s, %s, %s)' % (self.arrsig.debug_repr(),
-                                      self.xsig.debug_repr(),
-                                      self.ysig.debug_repr())
diff --git a/pypy/module/micronumpy/strides.py b/pypy/module/micronumpy/strides.py
--- a/pypy/module/micronumpy/strides.py
+++ b/pypy/module/micronumpy/strides.py
@@ -1,5 +1,6 @@
 from pypy.rlib import jit
 from pypy.interpreter.error import OperationError
+from pypy.module.micronumpy.base import W_NDimArray
 
 @jit.look_inside_iff(lambda chunks: jit.isconstant(len(chunks)))
 def enumerate_chunks(chunks):
@@ -48,11 +49,10 @@
     return rstrides, rbackstrides
 
 def is_single_elem(space, w_elem, is_rec_type):
-    from pypy.module.micronumpy.interp_numarray import BaseArray
     if (is_rec_type and space.isinstance_w(w_elem, space.w_tuple)):
         return True
     if (space.isinstance_w(w_elem, space.w_tuple) or
-        isinstance(w_elem, BaseArray) or    
+        isinstance(w_elem, W_NDimArray) or    
         space.isinstance_w(w_elem, space.w_list)):
         return False
     return True
@@ -104,7 +104,11 @@
             i //= shape[s]
     return coords, step, lngth
 
-def shape_agreement(space, shape1, shape2):
+def shape_agreement(space, shape1, w_arr2, broadcast_down=True):
+    if w_arr2 is None:
+        return shape1
+    assert isinstance(w_arr2, W_NDimArray)
+    shape2 = w_arr2.get_shape()
     ret = _shape_agreement(shape1, shape2)
     if len(ret) < max(len(shape1), len(shape2)):
         raise OperationError(space.w_ValueError,
@@ -113,6 +117,13 @@
                 ",".join([str(x) for x in shape2]),
             ))
         )
+    if not broadcast_down and len([x for x in ret if x != 1]) > len([x for x in shape2 if x != 1]):
+        raise OperationError(space.w_ValueError,
+            space.wrap("unbroadcastable shape (%s) cannot be broadcasted to (%s)" % (
+                ",".join([str(x) for x in shape1]),
+                ",".join([str(x) for x in shape2]),
+            ))
+        )
     return ret
 
 def _shape_agreement(shape1, shape2):
@@ -165,12 +176,6 @@
         neg_dim = -1
         batch = space.listview(w_iterable)
         new_size = 1
-        if len(batch) < 1:
-            if old_size == 1:
-                # Scalars can have an empty size.
-                new_size = 1
-            else:
-                new_size = 0
         new_shape = []
         i = 0
         for elem in batch:
diff --git a/pypy/module/micronumpy/support.py b/pypy/module/micronumpy/support.py
--- a/pypy/module/micronumpy/support.py
+++ b/pypy/module/micronumpy/support.py
@@ -7,3 +7,19 @@
     for x in s:
         i *= x
     return i
+
+def calc_strides(shape, dtype, order):
+    strides = []
+    backstrides = []
+    s = 1
+    shape_rev = shape[:]
+    if order == 'C':
+        shape_rev.reverse()
+    for sh in shape_rev:
+        strides.append(s * dtype.get_size())
+        backstrides.append(s * (sh - 1) * dtype.get_size())
+        s *= sh
+    if order == 'C':
+        strides.reverse()
+        backstrides.reverse()
+    return strides, backstrides
diff --git a/pypy/module/micronumpy/test/test_arrayops.py b/pypy/module/micronumpy/test/test_arrayops.py
--- a/pypy/module/micronumpy/test/test_arrayops.py
+++ b/pypy/module/micronumpy/test/test_arrayops.py
@@ -8,9 +8,78 @@
         a = where(array(a) > 0, ones(5), zeros(5))
         assert (a == [1, 1, 1, 0, 0]).all()
 
+    def test_where_differing_dtypes(self):
+        from _numpypy import array, ones, zeros, where
+        a = [1, 2, 3, 0, -3]
+        a = where(array(a) > 0, ones(5, dtype=int), zeros(5, dtype=float))
+        assert (a == [1, 1, 1, 0, 0]).all()
+
+    def test_where_broadcast(self):
+        from _numpypy import array, where
+        a = where(array([[1, 2, 3], [4, 5, 6]]) > 3, [1, 1, 1], 2)
+        assert (a == [[2, 2, 2], [1, 1, 1]]).all()
+        a = where(True, [1, 1, 1], 2)
+        assert (a == [1, 1, 1]).all()
+
+    def test_where_errors(self):
+        from _numpypy import where, array
+        raises(ValueError, "where([1, 2, 3], [3, 4, 5])")
+        raises(ValueError, "where([1, 2, 3], [3, 4, 5], [6, 7])")
+        assert where(True, 1, 2) == array(1)
+        assert where(False, 1, 2) == array(2)
+        assert (where(True, [1, 2, 3], 2) == [1, 2, 3]).all()
+        assert (where(False, 1, [1, 2, 3]) == [1, 2, 3]).all()
+        assert (where([1, 2, 3], True, False) == [True, True, True]).all()
+
+    #def test_where_1_arg(self):
+    #    xxx
+
     def test_where_invalidates(self):
         from _numpypy import where, ones, zeros, array
         a = array([1, 2, 3, 0, -3])
         b = where(a > 0, ones(5), zeros(5))
         a[0] = 0
         assert (b == [1, 1, 1, 0, 0]).all()
+
+
+    def test_dot(self):
+        from _numpypy import array, dot, arange
+        a = array(range(5))
+        assert dot(a, a) == 30.0
+
+        a = array(range(5))
+        assert a.dot(range(5)) == 30
+        assert dot(range(5), range(5)) == 30
+        assert (dot(5, [1, 2, 3]) == [5, 10, 15]).all()
+
+        a = arange(12).reshape(3, 4)
+        b = arange(12).reshape(4, 3)
+        c = a.dot(b)
+        assert (c == [[ 42, 48, 54], [114, 136, 158], [186, 224, 262]]).all()
+
+        a = arange(24).reshape(2, 3, 4)
+        raises(ValueError, "a.dot(a)")
+        b = a[0, :, :].T
+        #Superfluous shape test makes the intention of the test clearer
+        assert a.shape == (2, 3, 4)
+        assert b.shape == (4, 3)
+        c = dot(a, b)
+        assert (c == [[[14, 38, 62], [38, 126, 214], [62, 214, 366]],
+                   [[86, 302, 518], [110, 390, 670], [134, 478, 822]]]).all()
+        c = dot(a, b[:, 2])
+        assert (c == [[62, 214, 366], [518, 670, 822]]).all()
+        a = arange(3*2*6).reshape((3,2,6))
+        b = arange(3*2*6)[::-1].reshape((2,6,3))
+        assert dot(a, b)[2,0,1,2] == 1140
+        assert (dot([[1,2],[3,4]],[5,6]) == [17, 39]).all()
+
+    def test_dot_constant(self):
+        from _numpypy import array, dot
+        a = array(range(5))
+        b = a.dot(2.5)
+        for i in xrange(5):
+            assert b[i] == 2.5 * a[i]
+        c = dot(4, 3.0)
+        assert c == 12.0
+        c = array(3.0).dot(array(4))
+        assert c == 12.0
diff --git a/pypy/module/micronumpy/test/test_base.py b/pypy/module/micronumpy/test/test_base.py
--- a/pypy/module/micronumpy/test/test_base.py
+++ b/pypy/module/micronumpy/test/test_base.py
@@ -1,9 +1,7 @@
 from pypy.conftest import gettestobjspace
 from pypy.module.micronumpy.interp_dtype import get_dtype_cache
-from pypy.module.micronumpy.interp_numarray import W_NDimArray, Scalar
 from pypy.module.micronumpy.interp_ufuncs import (find_binop_result_dtype,
         find_unaryop_result_dtype)
-from pypy.module.micronumpy.interp_boxes import W_Float64Box
 from pypy.module.micronumpy.interp_dtype import nonnative_byteorder_prefix,\
      byteorder_prefix
 from pypy.conftest import option
@@ -21,59 +19,6 @@
         cls.w_non_native_prefix = cls.space.wrap(nonnative_byteorder_prefix)
         cls.w_native_prefix = cls.space.wrap(byteorder_prefix)
 
-class TestSignature(object):
-    def test_binop_signature(self, space):
-        float64_dtype = get_dtype_cache(space).w_float64dtype
-        bool_dtype = get_dtype_cache(space).w_booldtype
-
-        ar = W_NDimArray([10], dtype=float64_dtype)
-        ar2 = W_NDimArray([10], dtype=float64_dtype)
-        v1 = ar.descr_add(space, ar)
-        v2 = ar.descr_add(space, Scalar(float64_dtype, W_Float64Box(2.0)))
-        sig1 = v1.find_sig()
-        sig2 = v2.find_sig()
-        assert v1 is not v2
-        assert sig1.left.iter_no == sig1.right.iter_no
-        assert sig2.left.iter_no != sig2.right.iter_no
-        assert sig1.left.array_no == sig1.right.array_no
-        sig1b = ar2.descr_add(space, ar).find_sig()
-        assert sig1b.left.array_no != sig1b.right.array_no
-        assert sig1b is not sig1
-        v3 = ar.descr_add(space, Scalar(float64_dtype, W_Float64Box(1.0)))
-        sig3 = v3.find_sig()
-        assert sig2 is sig3
-        v4 = ar.descr_add(space, ar)
-        assert v1.find_sig() is v4.find_sig()
-
-        bool_ar = W_NDimArray([10], dtype=bool_dtype)
-        v5 = ar.descr_add(space, bool_ar)
-        assert v5.find_sig() is not v1.find_sig()
-        assert v5.find_sig() is not v2.find_sig()
-        v6 = ar.descr_add(space, bool_ar)
-        assert v5.find_sig() is v6.find_sig()
-        v7 = v6.descr_add(space, v6)
-        sig7 = v7.find_sig()
-        assert sig7.left.left.iter_no == sig7.right.left.iter_no
-        assert sig7.left.left.iter_no != sig7.right.right.iter_no
-        assert sig7.left.right.iter_no == sig7.right.right.iter_no
-        v1.forced_result = ar
-        assert v1.find_sig() is not sig1
-
-    def test_slice_signature(self, space):
-        float64_dtype = get_dtype_cache(space).w_float64dtype
-
-        ar = W_NDimArray([10], dtype=float64_dtype)
-        v1 = ar.descr_getitem(space, space.wrap(slice(1, 3, 1)))
-        v2 = ar.descr_getitem(space, space.wrap(slice(4, 6, 1)))
-        assert v1.find_sig() is v2.find_sig()
-
-        v3 = v2.descr_add(space, v1)
-        v4 = v1.descr_add(space, v2)
-        assert v3.find_sig() is v4.find_sig()
-        v5 = ar.descr_add(space, ar).descr_getitem(space, space.wrap(slice(1, 3, 1)))
-        v6 = ar.descr_add(space, ar).descr_getitem(space, space.wrap(slice(1, 4, 1)))
-        assert v5.find_sig() is v6.find_sig()
-
 class TestUfuncCoerscion(object):
     def test_binops(self, space):
         bool_dtype = get_dtype_cache(space).w_booldtype
diff --git a/pypy/module/micronumpy/test/test_compile.py b/pypy/module/micronumpy/test/test_compile.py
--- a/pypy/module/micronumpy/test/test_compile.py
+++ b/pypy/module/micronumpy/test/test_compile.py
@@ -1,4 +1,5 @@
 import py
+py.test.skip("this is going away")
 
 from pypy.module.micronumpy.compile import (numpy_compile, Assignment,
     ArrayConstant, FloatConstant, Operator, Variable, RangeConstant, Execute,
diff --git a/pypy/module/micronumpy/test/test_dtypes.py b/pypy/module/micronumpy/test/test_dtypes.py
--- a/pypy/module/micronumpy/test/test_dtypes.py
+++ b/pypy/module/micronumpy/test/test_dtypes.py
@@ -1,4 +1,4 @@
-import py
+import py, sys
 from pypy.conftest import option
 from pypy.module.micronumpy.test.test_base import BaseNumpyAppTest
 from pypy.interpreter.gateway import interp2app
@@ -508,13 +508,6 @@
         from _numpypy import dtype
         assert dtype('i4').alignment == 4
 
-    def test_typeinfo(self):
-        from _numpypy import typeinfo, void, number, int64, bool_
-        assert typeinfo['Number'] == number
-        assert typeinfo['LONGLONG'] == ('q', 9, 64, 8, 9223372036854775807L, -9223372036854775808L, int64)
-        assert typeinfo['VOID'] == ('V', 20, 0, 1, void)
-        assert typeinfo['BOOL'] == ('?', 0, 8, 1, 1, 0, bool_)
-
 class AppTestStrUnicodeDtypes(BaseNumpyAppTest):
     def test_str_unicode(self):
         from _numpypy import str_, unicode_, character, flexible, generic
@@ -583,14 +576,16 @@
     def setup_class(cls):
         BaseNumpyAppTest.setup_class.im_func(cls)
         def check_non_native(w_obj, w_obj2):
-            assert w_obj.storage[0] == w_obj2.storage[1]
-            assert w_obj.storage[1] == w_obj2.storage[0]
-            if w_obj.storage[0] == '\x00':
-                assert w_obj2.storage[1] == '\x00'
-                assert w_obj2.storage[0] == '\x01'
+            stor1 = w_obj.implementation.storage
+            stor2 = w_obj2.implementation.storage
+            assert stor1[0] == stor2[1]
+            assert stor1[1] == stor2[0]
+            if stor1[0] == '\x00':
+                assert stor2[1] == '\x00'
+                assert stor2[0] == '\x01'
             else:
-                assert w_obj2.storage[1] == '\x01'
-                assert w_obj2.storage[0] == '\x00'
+                assert stor2[1] == '\x01'
+                assert stor2[0] == '\x00'
         cls.w_check_non_native = cls.space.wrap(interp2app(check_non_native))
         if option.runappdirect:
             py.test.skip("not a direct test")
@@ -602,3 +597,15 @@
         assert (a + a)[1] == 4
         self.check_non_native(a, array([1, 2, 3], 'i2'))
 
+class AppTestPyPyOnly(BaseNumpyAppTest):
+    def setup_class(cls):
+        if option.runappdirect and '__pypy__' not in sys.builtin_module_names:
+            py.test.skip("pypy only test")
+        BaseNumpyAppTest.setup_class.im_func(cls)
+
+    def test_typeinfo(self):
+        from _numpypy import typeinfo, void, number, int64, bool_
+        assert typeinfo['Number'] == number
+        assert typeinfo['LONGLONG'] == ('q', 9, 64, 8, 9223372036854775807L, -9223372036854775808L, int64)
+        assert typeinfo['VOID'] == ('V', 20, 0, 1, void)
+        assert typeinfo['BOOL'] == ('?', 0, 8, 1, 1, 0, bool_)
diff --git a/pypy/module/micronumpy/test/test_iter.py b/pypy/module/micronumpy/test/test_iter.py
--- a/pypy/module/micronumpy/test/test_iter.py
+++ b/pypy/module/micronumpy/test/test_iter.py
@@ -1,4 +1,7 @@
-from pypy.module.micronumpy.interp_iter import ViewIterator
+from pypy.module.micronumpy.arrayimpl.concrete import MultiDimViewIterator
+
+class MockArray(object):
+    size = 1
 
 class TestIterDirect(object):
     def test_C_viewiterator(self):
@@ -9,36 +12,36 @@
         strides = [5, 1]
         backstrides = [x * (y - 1) for x,y in zip(strides, shape)]
         assert backstrides == [10, 4]
-        i = ViewIterator(start, strides, backstrides, shape)
-        i = i.next(2)
-        i = i.next(2)
-        i = i.next(2)
+        i = MultiDimViewIterator(MockArray, start, strides, backstrides, shape)
+        i.next()
+        i.next()
+        i.next()
         assert i.offset == 3
         assert not i.done()
-        assert i.indices == [0,3]
+        assert i.indexes == [0,3]
         #cause a dimension overflow
-        i = i.next(2)
-        i = i.next(2)
+        i.next()
+        i.next()
         assert i.offset == 5
-        assert i.indices == [1,0]
+        assert i.indexes == [1,0]
 
         #Now what happens if the array is transposed? strides[-1] != 1
         # therefore layout is non-contiguous
         strides = [1, 3]
         backstrides = [x * (y - 1) for x,y in zip(strides, shape)]
         assert backstrides == [2, 12]
-        i = ViewIterator(start, strides, backstrides, shape)
-        i = i.next(2)
-        i = i.next(2)
-        i = i.next(2)
+        i = MultiDimViewIterator(MockArray, start, strides, backstrides, shape)
+        i.next()
+        i.next()
+        i.next()
         assert i.offset == 9
         assert not i.done()
-        assert i.indices == [0,3]
+        assert i.indexes == [0,3]
         #cause a dimension overflow
-        i = i.next(2)
-        i = i.next(2)
+        i.next()
+        i.next()
         assert i.offset == 1
-        assert i.indices == [1,0]
+        assert i.indexes == [1,0]
 
     def test_C_viewiterator_step(self):
         #iteration in C order with #contiguous layout => strides[-1] is 1
@@ -48,22 +51,22 @@
         strides = [5, 1]
         backstrides = [x * (y - 1) for x,y in zip(strides, shape)]
         assert backstrides == [10, 4]
-        i = ViewIterator(start, strides, backstrides, shape)
-        i = i.next_skip_x(2,2)
-        i = i.next_skip_x(2,2)
-        i = i.next_skip_x(2,2)
+        i = MultiDimViewIterator(MockArray, start, strides, backstrides, shape)
+        i.next_skip_x(2)
+        i.next_skip_x(2)
+        i.next_skip_x(2)
         assert i.offset == 6
         assert not i.done()
-        assert i.indices == [1,1]
+        assert i.indexes == [1,1]
         #And for some big skips
-        i = i.next_skip_x(2,5)
+        i.next_skip_x(5)
         assert i.offset == 11
-        assert i.indices == [2,1]
-        i = i.next_skip_x(2,5)
+        assert i.indexes == [2,1]
+        i.next_skip_x(5)
         # Note: the offset does not overflow but recycles,
         # this is good for broadcast
         assert i.offset == 1
-        assert i.indices == [0,1]
+        assert i.indexes == [0,1]
         assert i.done()
 
         #Now what happens if the array is transposed? strides[-1] != 1
@@ -71,18 +74,18 @@
         strides = [1, 3]
         backstrides = [x * (y - 1) for x,y in zip(strides, shape)]
         assert backstrides == [2, 12]
-        i = ViewIterator(start, strides, backstrides, shape)
-        i = i.next_skip_x(2,2)
-        i = i.next_skip_x(2,2)
-        i = i.next_skip_x(2,2)
+        i = MultiDimViewIterator(MockArray, start, strides, backstrides, shape)
+        i.next_skip_x(2)
+        i.next_skip_x(2)
+        i.next_skip_x(2)
         assert i.offset == 4
-        assert i.indices == [1,1]
+        assert i.indexes == [1,1]
         assert not i.done()
-        i = i.next_skip_x(2,5)
+        i.next_skip_x(5)
         assert i.offset == 5
-        assert i.indices == [2,1]
+        assert i.indexes == [2,1]
         assert not i.done()
-        i = i.next_skip_x(2,5)
-        assert i.indices == [0,1]
+        i.next_skip_x(5)
+        assert i.indexes == [0,1]
         assert i.offset == 3
         assert i.done()
diff --git a/pypy/module/micronumpy/test/test_numarray.py b/pypy/module/micronumpy/test/test_numarray.py
--- a/pypy/module/micronumpy/test/test_numarray.py
+++ b/pypy/module/micronumpy/test/test_numarray.py
@@ -1,11 +1,10 @@
 
-import py
+import py, sys
 
 from pypy.conftest import option
-from pypy.interpreter.error import OperationError
 from pypy.module.micronumpy.appbridge import get_appbridge_cache
-from pypy.module.micronumpy.interp_iter import Chunk, Chunks
-from pypy.module.micronumpy.interp_numarray import W_NDimArray, shape_agreement
+from pypy.module.micronumpy.iter import Chunk, Chunks
+from pypy.module.micronumpy.interp_numarray import W_NDimArray
 from pypy.module.micronumpy.test.test_base import BaseNumpyAppTest
 
 class MockDtype(object):
@@ -14,12 +13,19 @@
         def malloc(size):
             return None
 
+        @staticmethod
+        def get_element_size():
+            return 1
+
     def get_size(self):
         return 1
 
 
 def create_slice(a, chunks):
-    return Chunks(chunks).apply(a)
+    return Chunks(chunks).apply(a).implementation
+
+def create_array(*args, **kwargs):
+    return W_NDimArray.from_shape(*args, **kwargs).implementation
 
 class TestNumArrayDirect(object):
     def newslice(self, *args):
@@ -35,17 +41,17 @@
         return self.space.newtuple(args_w)
 
     def test_strides_f(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), 'F')
+        a = create_array([10, 5, 3], MockDtype(), order='F')
         assert a.strides == [1, 10, 50]
         assert a.backstrides == [9, 40, 100]
 
     def test_strides_c(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), 'C')
+        a = create_array([10, 5, 3], MockDtype(), order='C')
         assert a.strides == [15, 3, 1]
         assert a.backstrides == [135, 12, 2]
 
     def test_create_slice_f(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), 'F')
+        a = create_array([10, 5, 3], MockDtype(), order='F')
         s = create_slice(a, [Chunk(3, 0, 0, 1)])
         assert s.start == 3
         assert s.strides == [10, 50]
@@ -63,7 +69,7 @@
         assert s.shape == [10, 3]
 
     def test_create_slice_c(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), 'C')
+        a = create_array([10, 5, 3], MockDtype(), order='C')
         s = create_slice(a, [Chunk(3, 0, 0, 1)])
         assert s.start == 45
         assert s.strides == [3, 1]
@@ -83,7 +89,7 @@
         assert s.shape == [10, 3]
 
     def test_slice_of_slice_f(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), 'F')
+        a = create_array([10, 5, 3], MockDtype(), order='F')
         s = create_slice(a, [Chunk(5, 0, 0, 1)])
         assert s.start == 5
         s2 = create_slice(s, [Chunk(3, 0, 0, 1)])
@@ -100,7 +106,7 @@
         assert s2.start == 1 * 15 + 2 * 3
 
     def test_slice_of_slice_c(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), order='C')
+        a = create_array([10, 5, 3], MockDtype(), order='C')
         s = create_slice(a, [Chunk(5, 0, 0, 1)])
         assert s.start == 15 * 5
         s2 = create_slice(s, [Chunk(3, 0, 0, 1)])
@@ -117,51 +123,30 @@
         assert s2.start == 1 * 15 + 2 * 3
 
     def test_negative_step_f(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), 'F')
+        a = create_array([10, 5, 3], MockDtype(), order='F')
         s = create_slice(a, [Chunk(9, -1, -2, 5)])
         assert s.start == 9
         assert s.strides == [-2, 10, 50]
         assert s.backstrides == [-8, 40, 100]
 
     def test_negative_step_c(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), order='C')
+        a = create_array([10, 5, 3], MockDtype(), order='C')
         s = create_slice(a, [Chunk(9, -1, -2, 5)])
         assert s.start == 135
         assert s.strides == [-30, 3, 1]
         assert s.backstrides == [-120, 12, 2]
 
-    def test_index_of_single_item_f(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), 'F')
-        r = a._index_of_single_item(self.space, self.newtuple(1, 2, 2))
-        assert r == 1 + 2 * 10 + 2 * 50
-        s = create_slice(a, [Chunk(0, 10, 1, 10), Chunk(2, 0, 0, 1)])
-        r = s._index_of_single_item(self.space, self.newtuple(1, 0))
-        assert r == a._index_of_single_item(self.space, self.newtuple(1, 2, 0))
-        r = s._index_of_single_item(self.space, self.newtuple(1, 1))
-        assert r == a._index_of_single_item(self.space, self.newtuple(1, 2, 1))
-
-    def test_index_of_single_item_c(self):
-        a = W_NDimArray([10, 5, 3], MockDtype(), 'C')
-        r = a._index_of_single_item(self.space, self.newtuple(1, 2, 2))
-        assert r == 1 * 3 * 5 + 2 * 3 + 2
-        s = create_slice(a, [Chunk(0, 10, 1, 10), Chunk(2, 0, 0, 1)])
-        r = s._index_of_single_item(self.space, self.newtuple(1, 0))
-        assert r == a._index_of_single_item(self.space, self.newtuple(1, 2, 0))
-        r = s._index_of_single_item(self.space, self.newtuple(1, 1))
-        assert r == a._index_of_single_item(self.space, self.newtuple(1, 2, 1))
-
     def test_shape_agreement(self):
-        assert shape_agreement(self.space, [3], [3]) == [3]
-        assert shape_agreement(self.space, [1, 2, 3], [1, 2, 3]) == [1, 2, 3]
-        py.test.raises(OperationError, shape_agreement, self.space, [2], [3])
-        assert shape_agreement(self.space, [4, 4], []) == [4, 4]
-        assert shape_agreement(self.space,
-                [8, 1, 6, 1], [7, 1, 5]) == [8, 7, 6, 5]
-        assert shape_agreement(self.space,
-                [5, 2], [4, 3, 5, 2]) == [4, 3, 5, 2]
+        from pypy.module.micronumpy.strides import _shape_agreement
+        assert _shape_agreement([3], [3]) == [3]
+        assert _shape_agreement([1, 2, 3], [1, 2, 3]) == [1, 2, 3]
+        _shape_agreement([2], [3]) == 0
+        assert _shape_agreement([4, 4], []) == [4, 4]
+        assert _shape_agreement([8, 1, 6, 1], [7, 1, 5]) == [8, 7, 6, 5]
+        assert _shape_agreement([5, 2], [4, 3, 5, 2]) == [4, 3, 5, 2]
 
     def test_calc_new_strides(self):
-        from pypy.module.micronumpy.interp_numarray import calc_new_strides
+        from pypy.module.micronumpy.strides import calc_new_strides
         assert calc_new_strides([2, 4], [4, 2], [4, 2], "C") == [8, 2]
         assert calc_new_strides([2, 4, 3], [8, 3], [1, 16], 'F') == [1, 2, 16]
         assert calc_new_strides([2, 3, 4], [8, 3], [1, 16], 'F') is None
@@ -251,6 +236,8 @@
         a = ndarray(3, dtype=int)
         assert a.shape == (3,)
         assert a.dtype is dtype(int)
+        a = ndarray([], dtype=float)
+        assert a.shape == ()
 
     def test_ndmin(self):
         from _numpypy import array
@@ -281,7 +268,7 @@
         assert x.ndim == 3
         # numpy actually raises an AttributeError, but _numpypy raises an
         # TypeError
-        raises(TypeError, 'x.ndim = 3')
+        raises((TypeError, AttributeError), 'x.ndim = 3')
 
     def test_init(self):
         from _numpypy import zeros
@@ -464,7 +451,7 @@
         assert a[1] == 0.
         assert a[3] == 1.
         b[::-1] = b
-        assert b[0] == 0.
+        assert b[0] == 1.
         assert b[1] == 0.
 
     def test_setslice_of_slice_array(self):
@@ -589,7 +576,7 @@
     def test_set_shape(self):
         from _numpypy import array, zeros
         a = array([])
-        a.shape = []
+        raises(ValueError, "a.shape = []")
         a = array(range(12))
         a.shape = (3, 4)
         assert (a == [range(4), range(4, 8), range(8, 12)]).all()
@@ -605,6 +592,7 @@
         a.shape = ()
         #numpy allows this
         a.shape = (1,)
+        assert a[0] == 3
         a = array(range(6)).reshape(2,3).T
         raises(AttributeError, 'a.shape = 6')
 
@@ -1094,7 +1082,7 @@
         assert a[:4].mean() == 1.5
         a = array(range(105)).reshape(3, 5, 7)
         b = a.mean(axis=0)
-        b[0, 0]==35.
+        assert b[0, 0] == 35.
         assert a.mean(axis=0)[0, 0] == 35
         assert (b == array(range(35, 70), dtype=float).reshape(5, 7)).all()
         assert (a.mean(2) == array(range(0, 15), dtype=float).reshape(3, 5) * 7 + 3).all()
@@ -1102,6 +1090,8 @@
         assert (a.mean(axis=-1) == a.mean(axis=2)).all()
         raises(ValueError, a.mean, -4)
         raises(ValueError, a.mean, 3)
+        a = arange(10).reshape(5, 2)
+        assert (a.mean(1) == [0.5, 2.5, 4.5, 6.5, 8.5]).all()
 
     def test_sum(self):
         from _numpypy import array
@@ -1117,7 +1107,7 @@
         d = array(0.)
         b = a.sum(out=d)
         assert b == d
-        assert isinstance(b, float)
+        assert b is d
 
     def test_reduce_nd(self):
         from numpypy import arange, array, multiply
@@ -1272,48 +1262,6 @@
         c = array([])
         assert c.any() == False
 
-    def test_dot(self):
-        from _numpypy import array, dot, arange
-        a = array(range(5))
-        assert dot(a, a) == 30.0
-
-        a = array(range(5))
-        assert a.dot(range(5)) == 30
-        assert dot(range(5), range(5)) == 30
-        assert (dot(5, [1, 2, 3]) == [5, 10, 15]).all()
-
-        a = arange(12).reshape(3, 4)
-        b = arange(12).reshape(4, 3)
-        c = a.dot(b)
-        assert (c == [[ 42, 48, 54], [114, 136, 158], [186, 224, 262]]).all()
-
-        a = arange(24).reshape(2, 3, 4)
-        raises(ValueError, "a.dot(a)")
-        b = a[0, :, :].T
-        #Superfluous shape test makes the intention of the test clearer
-        assert a.shape == (2, 3, 4)
-        assert b.shape == (4, 3)
-        c = dot(a, b)
-        assert (c == [[[14, 38, 62], [38, 126, 214], [62, 214, 366]],
-                   [[86, 302, 518], [110, 390, 670], [134, 478, 822]]]).all()
-        c = dot(a, b[:, 2])
-        assert (c == [[62, 214, 366], [518, 670, 822]]).all()
-        a = arange(3*2*6).reshape((3,2,6))
-        b = arange(3*2*6)[::-1].reshape((2,6,3))
-        assert dot(a, b)[2,0,1,2] == 1140
-        assert (dot([[1,2],[3,4]],[5,6]) == [17, 39]).all()
-
-    def test_dot_constant(self):
-        from _numpypy import array, dot
-        a = array(range(5))
-        b = a.dot(2.5)
-        for i in xrange(5):
-            assert b[i] == 2.5 * a[i]
-        c = dot(4, 3.0)
-        assert c == 12.0
-        c = array(3.0).dot(array(4))
-        assert c == 12.0
-
     def test_dtype_guessing(self):
         from _numpypy import array, dtype, float64, int8, bool_
 
@@ -1364,36 +1312,12 @@
         from _numpypy import array
         a = array(range(5))
         a[::-1] = a
-        assert (a == [0, 1, 2, 1, 0]).all()
+        assert (a == [4, 3, 2, 1, 0]).all()
         # but we force intermediates
         a = array(range(5))
         a[::-1] = a + a
         assert (a == [8, 6, 4, 2, 0]).all()
 
-    def test_debug_repr(self):
-        from _numpypy import zeros, sin
-        from _numpypy.pypy import debug_repr
-        a = zeros(1)
-        assert debug_repr(a) == 'Array'
-        assert debug_repr(a + a) == 'Call2(add, Array, Array)'
-        assert debug_repr(a[::2]) == 'Slice'
-        assert debug_repr(a + 2) == 'Call2(add, Array, Scalar)'
-        assert debug_repr(a + a.flat) == 'Call2(add, Array, Flat)'
-        assert debug_repr(sin(a)) == 'Call1(sin, Array)'
-
-        b = a + a
-        b[0] = 3
-        assert debug_repr(b) == 'Array'
-
-    def test_remove_invalidates(self):
-        from _numpypy import array
-        from _numpypy.pypy import remove_invalidates
-        a = array([1, 2, 3])
-        b = a + a
-        remove_invalidates(a)
-        a[0] = 14
-        assert b[0] == 28
-
     def test_virtual_views(self):
         from _numpypy import arange
         a = arange(15)
@@ -1484,16 +1408,16 @@
         f = concatenate((f1, [2], f1, [7]))
         assert (f == [0,1,2,0,1,7]).all()
 
-        bad_axis = raises(ValueError, concatenate, (a1,a2), axis=1)
-        assert str(bad_axis.value) == "bad axis argument"
+        bad_axis = raises(IndexError, concatenate, (a1,a2), axis=1)
+        assert str(bad_axis.value) == "axis 1 out of bounds [0, 1)"
 
         concat_zero = raises(ValueError, concatenate, ())
         assert str(concat_zero.value) == \
-            "concatenation of zero-length sequences is impossible"
+            "need at least one array to concatenate"
 
         dims_disagree = raises(ValueError, concatenate, (a1, b1), axis=0)
         assert str(dims_disagree.value) == \
-            "array dimensions must agree except for axis being concatenated"
+            "all the input arrays must have same number of dimensions"
         a = array([1, 2, 3, 4, 5, 6])
         a = (a + a)[::2]
         b = concatenate((a[:3], a[-3:]))
@@ -1586,6 +1510,7 @@
         # test virtual
         assert ((x + x).swapaxes(0,1) == array([[[ 2,  4,  6], [14, 16, 18]], 
                                          [[ 8, 10, 12], [20, 22, 24]]])).all()
+        assert array(1).swapaxes(10, 12) == 1
 
     def test_filter_bug(self):
         from numpypy import array
@@ -1655,18 +1580,6 @@
         assert a[0][1][1] == 13
         assert a[1][2][1] == 15
 
-    def test_init_2(self):
-        import _numpypy
-        raises(ValueError, _numpypy.array, [[1], 2])
-        raises(ValueError, _numpypy.array, [[1, 2], [3]])
-        raises(ValueError, _numpypy.array, [[[1, 2], [3, 4], 5]])
-        raises(ValueError, _numpypy.array, [[[1, 2], [3, 4], [5]]])
-        a = _numpypy.array([[1, 2], [4, 5]])
-        assert a[0, 1] == 2
-        assert a[0][1] == 2
-        a = _numpypy.array(([[[1, 2], [3, 4], [5, 6]]]))
-        assert (a[0, 1] == [3, 4]).all()
-
     def test_setitem_slice(self):
         import _numpypy
         a = _numpypy.zeros((3, 4))
@@ -1789,8 +1702,7 @@
         a = zeros((4, 3, 2))
         b = zeros((4, 2))
         exc = raises(ValueError, lambda: a + b)
-        assert str(exc.value) == "operands could not be broadcast" \
-            " together with shapes (4,3,2) (4,2)"
+        assert str(exc.value).startswith("operands could not be broadcast")
 
     def test_reduce(self):
         from _numpypy import array
@@ -1799,6 +1711,7 @@
         b = a[1:, 1::2]
         c = b + b
         assert c.sum() == (6 + 8 + 10 + 12) * 2
+        assert isinstance(c.sum(dtype='f8'), float)
 
     def test_transpose(self):
         from _numpypy import array
@@ -1860,6 +1773,8 @@
         b.next()
         b.next()
         b.next()
+        assert b.index == 3
+        assert b.coords == (0, 3)
         assert b[3] == 3
         assert (b[::3] == [0, 3, 6, 9]).all()
         assert (b[2::5] == [2, 7]).all()
@@ -1867,20 +1782,18 @@
         raises(IndexError, "b[11]")
         raises(IndexError, "b[-11]")
         raises(IndexError, 'b[0, 1]')
-        assert b.index == 3
-        assert b.coords == (0,3)
+        assert b.index == 0
+        assert b.coords == (0, 0)
 
     def test_flatiter_setitem(self):
         from _numpypy import arange, array
         a = arange(12).reshape(3,4)
         b = a.T.flat
         b[6::2] = [-1, -2]
-        print a == [[0, 1, -1, 3], [4, 5, 6, -1], [8, 9, -2, 11]]
         assert (a == [[0, 1, -1, 3], [4, 5, 6, -1], [8, 9, -2, 11]]).all()
         b[0:2] = [[[100]]]
         assert(a[0,0] == 100)
         assert(a[1,0] == 100)
-        raises(IndexError, 'b[array([10, 11])] == [-20, -40]')
 
     def test_flatiter_ops(self):
         from _numpypy import arange, array
@@ -1934,7 +1847,6 @@
         a = a[::2]
         i = a.__array_interface__
         assert isinstance(i['data'][0], int)
-        raises(TypeError, getattr, array(3), '__array_interface__')
 
     def test_array_indexing_one_elem(self):
         skip("not yet")
@@ -2006,12 +1918,6 @@
         assert array(x, copy=False) is x
         assert array(x, copy=True) is not x
 
-    def test_isna(self):
-        from _numpypy import isna, array
-        # XXX for now
-        assert not isna(3)
-        assert (isna(array([1, 2, 3, 4])) == [False, False, False, False]).all()
-
     def test_ravel(self):
         from _numpypy import arange
         assert (arange(3).ravel() == arange(3)).all()
@@ -2019,6 +1925,7 @@
         assert (arange(6).reshape(2, 3).T.ravel() == [0, 3, 1, 4, 2, 5]).all()
 
     def test_take(self):
+        skip("we wait for int-based indexing")
         from _numpypy import arange
         assert (arange(10).take([1, 2, 1, 1]) == [1, 2, 1, 1]).all()
         raises(IndexError, "arange(3).take([15])")
@@ -2044,21 +1951,16 @@
         assert type(array(3).item()) is int
         assert type(array(True).item()) is bool
         assert type(array(3.5).item()) is float
-        raises((ValueError, IndexError), "array(3).item(15)")
-        raises(ValueError, "array([1, 2, 3]).item()")
+        raises(IndexError, "array(3).item(15)")
+        raises(IndexError, "array([1, 2, 3]).item()")
         assert array([3]).item(0) == 3
         assert type(array([3]).item(0)) is int
         assert array([1, 2, 3]).item(-1) == 3
         a = array([1, 2, 3])
         assert a[::2].item(1) == 3
         assert (a + a).item(1) == 4
-        raises(ValueError, "array(5).item(1)")
+        raises(IndexError, "array(5).item(1)")
         assert array([1]).item() == 1
-
-    def test_count_nonzero(self):
-        from _numpypy import array
-        a = array([1,0,5,0,10])
-        assert a.count_nonzero() == 3
  
 
 class AppTestSupport(BaseNumpyAppTest):
@@ -2127,7 +2029,7 @@
         r = fromstring("\x01\x00\x02", dtype='bool')
         assert (r == [True, False, True]).all()
         s = fromstring("1,2,3,,5", dtype=bool, sep=",")
-        assert (s == [True, True, True, False, True]).all()
+        assert (s == [True, True, True, True, True]).all()
         t = fromstring("", bool)
         assert (t == []).all()
         u = fromstring("\x01\x00\x00\x00\x00\x00\x00\x00", dtype=int)
@@ -2241,8 +2143,8 @@
     def test_views(self):
         from _numpypy import array
         a = array([(1, 2), (3, 4)], dtype=[('x', int), ('y', float)])
-        raises(ValueError, 'array([1])["x"]')
-        raises(ValueError, 'a["z"]')
+        raises((IndexError, ValueError), 'array([1])["x"]')
+        raises((IndexError, ValueError), 'a["z"]')
         assert a['x'][1] == 3
         assert a['y'][1] == 4
         a['x'][0] = 15
@@ -2275,3 +2177,21 @@
         assert arr[1]['y']['x'] == 0.0
         assert arr[1]['x'] == 15
         
+class AppTestPyPy(BaseNumpyAppTest):
+    def setup_class(cls):
+        if option.runappdirect and '__pypy__' not in sys.builtin_module_names:
+            py.test.skip("pypy only test")
+        BaseNumpyAppTest.setup_class.im_func(cls)
+    
+    def test_init_2(self):
+        # this test is pypy only since in numpy it becomes an object dtype
+        import _numpypy
+        raises(ValueError, _numpypy.array, [[1], 2])
+        raises(ValueError, _numpypy.array, [[1, 2], [3]])
+        raises(ValueError, _numpypy.array, [[[1, 2], [3, 4], 5]])
+        raises(ValueError, _numpypy.array, [[[1, 2], [3, 4], [5]]])
+        a = _numpypy.array([[1, 2], [4, 5]])
+        assert a[0, 1] == 2
+        assert a[0][1] == 2
+        a = _numpypy.array(([[[1, 2], [3, 4], [5, 6]]]))
+        assert (a[0, 1] == [3, 4]).all()
diff --git a/pypy/module/micronumpy/test/test_outarg.py b/pypy/module/micronumpy/test/test_outarg.py
--- a/pypy/module/micronumpy/test/test_outarg.py
+++ b/pypy/module/micronumpy/test/test_outarg.py
@@ -108,19 +108,6 @@
         d = array([16, 16], dtype=int)
         b = sum(d, out=c)
         assert b == c
-        try:
-            from _numpypy import version
-            v = version.version.split('.')
-        except:
-            v = ['1', '6', '0'] # numpypy is api compatable to what version?
-        if v[0]<'2':
-            b = negative(c, out=a)
-            assert b == a
-            b = add(c, c, out=a)
-            assert b == a
-            b = sum(array([16, 16], dtype=float), out=a)
-            assert b == a
-        else:
-            cast_error = raises(TypeError, negative, c, a)
-            assert str(cast_error.value) == \
-            "Cannot cast ufunc negative output from dtype('float64') to dtype('int64') with casting rule 'same_kind'"
+        #cast_error = raises(TypeError, negative, c, a)
+        #assert str(cast_error.value) == \
+        #       "Cannot cast ufunc negative output from dtype('float64') to dtype('int64') with casting rule 'same_kind'"
diff --git a/pypy/module/micronumpy/test/test_ufuncs.py b/pypy/module/micronumpy/test/test_ufuncs.py
--- a/pypy/module/micronumpy/test/test_ufuncs.py
+++ b/pypy/module/micronumpy/test/test_ufuncs.py
@@ -7,7 +7,7 @@
 
         assert isinstance(add, ufunc)
         assert repr(add) == "<ufunc 'add'>"
-        assert repr(ufunc) == "<type 'numpypy.ufunc'>"
+        assert repr(ufunc) == "<type 'numpypy.ufunc'>" or repr(ufunc) == "<type 'numpy.ufunc'>"
 
     def test_ufunc_attrs(self):
         from _numpypy import add, multiply, sin
@@ -113,6 +113,7 @@
         assert (divide(array([-10]), array([2])) == array([-5])).all()
 
     def test_true_divide(self):
+        import math
         from _numpypy import array, true_divide
 
         a = array([0, 1, 2, 3, 4, 1, -1])
@@ -144,8 +145,8 @@
         assert (fmax(a, [ninf]*5) == a).all()
         assert (fmax(a, [inf]*5) == [inf]*5).all()
         assert (fmax(a, [1]*5) == [1, 1, 1, 5, inf]).all()
-        assert math.isnan(fmax(nan, 0))
-        assert math.isnan(fmax(0, nan))
+        assert fmax(nan, 0) == 0
+        assert fmax(0, nan) == 0
         assert math.isnan(fmax(nan, nan))
         # The numpy docs specify that the FIRST NaN should be used if both are NaN
         # Since comparisons with nnan and nan all return false,
@@ -164,8 +165,8 @@
         assert (fmin(a, [ninf]*5) == [ninf]*5).all()
         assert (fmin(a, [inf]*5) == a).all()
         assert (fmin(a, [1]*5) == [ninf, -5, 0, 1, 1]).all()
-        assert math.isnan(fmin(nan, 0))
-        assert math.isnan(fmin(0, nan))
+        assert fmin(nan, 0) == 0
+        assert fmin(0, nan) == 0
         assert math.isnan(fmin(nan, nan))
         # The numpy docs specify that the FIRST NaN should be used if both are NaN
         # use copysign on both sides to sidestep bug in nan representaion
@@ -227,11 +228,6 @@
         for i in range(10):
             assert a[i] == ref[i]
 
-        a = sign(array([True, False], dtype=bool))
-        assert a.dtype == dtype("int8")
-        assert a[0] == 1
-        assert a[1] == 0
-
     def test_signbit(self):
         from _numpypy import signbit
 
@@ -345,7 +341,7 @@
             assert b[i] == math.sin(a[i])
 
         a = sin(array([True, False], dtype=bool))
-        assert abs(a[0] - sin(1)) < 1e-7  # a[0] will be less precise
+        assert abs(a[0] - sin(1)) < 1e-3  # a[0] will be very imprecise
         assert a[1] == 0.0
 
     def test_cos(self):
@@ -557,7 +553,7 @@
         from _numpypy import sin, add
 
         raises(ValueError, sin.reduce, [1, 2, 3])
-        raises((ValueError, TypeError), add.reduce, 1)
+        assert add.reduce(1) == 1
 
     def test_reduce_1d(self):
         from _numpypy import add, maximum, less
@@ -631,23 +627,16 @@
             ]:
                 assert ufunc(a, b) == func(a, b)
 
-    def test_count_reduce_items(self):
-        from _numpypy import count_reduce_items, arange
-        a = arange(24).reshape(2, 3, 4)
-        assert count_reduce_items(a) == 24
-        assert count_reduce_items(a, 1) == 3
-        assert count_reduce_items(a, (1, 2)) == 3 * 4
-        raises(ValueError, count_reduce_items, a, -4)
-        raises(ValueError, count_reduce_items, a, (0, 2, -4))
 
     def test_count_nonzero(self):
-        from _numpypy import where, count_nonzero, arange
-        a = arange(10)
-        assert count_nonzero(a) == 9
-        a[9] = 0
-        assert count_nonzero(a) == 8
+        from _numpypy import count_nonzero
+        assert count_nonzero(0) == 0
+        assert count_nonzero(1) == 1
+        assert count_nonzero([]) == 0
+        assert count_nonzero([1, 2, 0]) == 2
+        assert count_nonzero([[1, 2, 0], [1, 0, 2]]) == 4
 
-    def test_true_divide(self):
+    def test_true_divide_2(self):
         from _numpypy import arange, array, true_divide
         assert (true_divide(arange(3), array([2, 2, 2])) == array([0, 0.5, 1])).all()
 
diff --git a/pypy/module/micronumpy/test/test_zjit.py b/pypy/module/micronumpy/test/test_zjit.py
--- a/pypy/module/micronumpy/test/test_zjit.py
+++ b/pypy/module/micronumpy/test/test_zjit.py
@@ -4,6 +4,7 @@
 """
 
 import py
+py.test.skip("this is going away")
 
 from pypy.jit.metainterp import pyjitpl
 from pypy.jit.metainterp.test.support import LLJitMixin
diff --git a/pypy/module/micronumpy/test/test_ztranslation.py b/pypy/module/micronumpy/test/test_ztranslation.py
--- a/pypy/module/micronumpy/test/test_ztranslation.py
+++ b/pypy/module/micronumpy/test/test_ztranslation.py
@@ -1,8 +1,4 @@
-from pypy.module.micronumpy import signature
 from pypy.objspace.fake.checkmodule import checkmodule
 
 def test_numpy_translates():
-    # XXX: If there are signatures floating around this might explode. This fix
-    # is ugly.
-    signature.known_sigs.clear()
     checkmodule('micronumpy')
diff --git a/pypy/module/micronumpy/types.py b/pypy/module/micronumpy/types.py
--- a/pypy/module/micronumpy/types.py
+++ b/pypy/module/micronumpy/types.py
@@ -4,11 +4,12 @@
 
 from pypy.interpreter.error import OperationError
 from pypy.module.micronumpy import interp_boxes
+from pypy.module.micronumpy.arrayimpl.voidbox import VoidBoxStorage
 from pypy.objspace.std.floatobject import float2string
 from pypy.rlib import rfloat, clibffi
 from pypy.rlib.rawstorage import (alloc_raw_storage, raw_storage_setitem,
                                   raw_storage_getitem)
-from pypy.rlib.objectmodel import specialize, we_are_translated
+from pypy.rlib.objectmodel import specialize
 from pypy.rlib.rarithmetic import widen, byteswap
 from pypy.rpython.lltypesystem import lltype, rffi
 from pypy.rlib.rstruct.runpack import runpack
@@ -279,7 +280,7 @@
         return int(v)
 
     def default_fromstring(self, space):
-        return self.box(False)
+        return self.box(True)
 
     @simple_binary_op
     def bitwise_and(self, v1, v2):
@@ -616,17 +617,21 @@
     @simple_binary_op
     def fmax(self, v1, v2):
         if math.isnan(v1):
+            if math.isnan(v2):
+                return v1
+            return v2
+        elif math.isnan(v2):
             return v1
-        elif math.isnan(v2):
-            return v2
         return max(v1, v2)
 
     @simple_binary_op
     def fmin(self, v1, v2):
         if math.isnan(v1):
+            if math.isnan(v2):
+                return v1
+            return v2
+        elif math.isnan(v2):
             return v1
-        elif math.isnan(v2):
-            return v2
         return min(v1, v2)
 
     @simple_binary_op
@@ -931,8 +936,6 @@
 
     @jit.unroll_safe
     def coerce(self, space, dtype, w_item):
-        from pypy.module.micronumpy.interp_numarray import W_NDimArray
-
         if isinstance(w_item, interp_boxes.W_VoidBox):
             return w_item
         # we treat every sequence as sequence, no special support
@@ -944,16 +947,14 @@
             raise OperationError(space.w_ValueError, space.wrap(
                 "wrong length"))
         items_w = space.fixedview(w_item)
-        # XXX optimize it out one day, but for now we just allocate an
-        #     array
-        arr = W_NDimArray([1], dtype)
+        arr = VoidBoxStorage(self.size, dtype)
         for i in range(len(items_w)):
             subdtype = dtype.fields[dtype.fieldnames[i]][1]
             ofs, itemtype = self.offsets_and_fields[i]
             w_item = items_w[i]
             w_box = itemtype.coerce(space, subdtype, w_item)
             itemtype.store(arr, 0, ofs, w_box)
-        return interp_boxes.W_VoidBox(arr, 0, arr.dtype)
+        return interp_boxes.W_VoidBox(arr, 0, dtype)
 
     @jit.unroll_safe
     def store(self, arr, i, ofs, box):
diff --git a/pypy/rlib/rawstorage.py b/pypy/rlib/rawstorage.py
--- a/pypy/rlib/rawstorage.py
+++ b/pypy/rlib/rawstorage.py
@@ -3,10 +3,12 @@
 from pypy.rpython.lltypesystem import lltype, rffi, llmemory
 from pypy.annotation import model as annmodel
 from pypy.rlib.rgc import lltype_is_gc
+from pypy.rlib.objectmodel import specialize
 
 RAW_STORAGE = rffi.CCHARP.TO
 RAW_STORAGE_PTR = rffi.CCHARP
 
+ at specialize.arg(1, 2)
 def alloc_raw_storage(size, track_allocation=True, zero=False):
     return lltype.malloc(RAW_STORAGE, size, flavor='raw',
                          add_memory_pressure=True,
@@ -22,6 +24,7 @@
     TP = rffi.CArrayPtr(lltype.typeOf(item))
     rffi.cast(TP, rffi.ptradd(storage, index))[0] = item
 
+ at specialize.arg(1)
 def free_raw_storage(storage, track_allocation=True):
     lltype.free(storage, flavor='raw', track_allocation=track_allocation)
 


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