[Scipy-svn] r7101 - trunk/scipy/misc

[scipy-svn at scipy.org]

Author: warren.weckesser
Date: 2011-01-29 14:54:21 -0600 (Sat, 29 Jan 2011)
New Revision: 7101

Modified:
   trunk/scipy/misc/common.py
   trunk/scipy/misc/pilutil.py
Log:
ENH: misc: Don't use plain assert for argument validation.

Modified: trunk/scipy/misc/common.py
===================================================================
--- trunk/scipy/misc/common.py	2011-01-29 20:17:35 UTC (rev 7100)
+++ trunk/scipy/misc/common.py	2011-01-29 20:54:21 UTC (rev 7101)
@@ -217,7 +217,7 @@
         sv = special.errprint(sv)
         return where(cond, vals, 0.0)
 
-def central_diff_weights(Np,ndiv=1):
+def central_diff_weights(Np, ndiv=1):
     """
     Return weights for an Np-point central derivative of order ndiv
     assuming equally-spaced function points.
@@ -230,8 +230,10 @@
     Can be inaccurate for large number of points.
 
     """
-    assert (Np >= ndiv+1), "Number of points must be at least the derivative order + 1."
-    assert (Np % 2 == 1), "Odd-number of points only."
+    if Np < ndiv + 1:
+        raise ValueError("Number of points must be at least the derivative order + 1.")
+    if Np % 2 == 0:
+        raise ValueError("The number of points must be odd.")
     from scipy import linalg
     ho = Np >> 1
     x = arange(-ho,ho+1.0)
@@ -242,7 +244,7 @@
     w = product(arange(1,ndiv+1),axis=0)*linalg.inv(X)[ndiv]
     return w
 
-def derivative(func,x0,dx=1.0,n=1,args=(),order=3):
+def derivative(func, x0, dx=1.0, n=1, args=(), order=3):
     """
     Find the n-th derivative of a function at point x0.
 
@@ -277,8 +279,12 @@
     4.0
 
     """
-    assert (order >= n+1), "Number of points must be at least the derivative order + 1."
-    assert (order % 2 == 1), "Odd number of points only."
+    if order < n + 1:
+        raise ValueError("'order' (the number of points used to compute the derivative), "
+                         "must be at least the derivative order 'n' + 1.")
+    if order % 2 == 0:
+        raise ValueError("'order' (the number of points used to compute the derivative) "
+                         "must be odd.")
     # pre-computed for n=1 and 2 and low-order for speed.
     if n==1:
         if order == 3:

Modified: trunk/scipy/misc/pilutil.py
===================================================================
--- trunk/scipy/misc/pilutil.py	2011-01-29 20:17:35 UTC (rev 7100)
+++ trunk/scipy/misc/pilutil.py	2011-01-29 20:54:21 UTC (rev 7101)
@@ -147,8 +147,9 @@
     return array(im)
 
 _errstr = "Mode is unknown or incompatible with input array shape."
-def toimage(arr,high=255,low=0,cmin=None,cmax=None,pal=None,
-            mode=None,channel_axis=None):
+
+def toimage(arr, high=255, low=0, cmin=None, cmax=None, pal=None,
+            mode=None, channel_axis=None):
     """Takes a numpy array and returns a PIL image.  The mode of the
     PIL image depends on the array shape, the pal keyword, and the mode
     keyword.
@@ -171,7 +172,8 @@
     shape = list(data.shape)
     valid = len(shape)==2 or ((len(shape)==3) and \
                               ((3 in shape) or (4 in shape)))
-    assert valid, "Not a suitable array shape for any mode."
+    if not valid:
+        raise ValueError("'arr' does not have a suitable array shape for any mode.")
     if len(shape) == 2:
         shape = (shape[1],shape[0]) # columns show up first
         if mode == 'F':
@@ -242,11 +244,13 @@
         raise ValueError(_errstr)
 
     if mode in ['RGB', 'YCbCr']:
-        assert numch == 3, "Invalid array shape for mode."
+        if numch != 3:
+            raise ValueError("Invalid array shape for mode.")
     if mode in ['RGBA', 'CMYK']:
-        assert numch == 4, "Invalid array shape for mode."
+        if numch != 4:
+            raise ValueError("Invalid array shape for mode.")
 
-    # Here we know data and mode is coorect
+    # Here we know data and mode is correct
     image = Image.fromstring(mode, shape, strdata)
     return image