[Numpy-svn] r3751 - in trunk/numpy: . core
numpy-svn at scipy.org
numpy-svn at scipy.org
Sat May 12 15:58:50 EDT 2007
Author: charris
Date: 2007-05-12 14:58:43 -0500 (Sat, 12 May 2007)
New Revision: 3751
Modified:
trunk/numpy/add_newdocs.py
trunk/numpy/core/defmatrix.py
trunk/numpy/core/fromnumeric.py
Log:
Add/edit documentation for mean, std, var.
Modified: trunk/numpy/add_newdocs.py
===================================================================
--- trunk/numpy/add_newdocs.py 2007-05-11 23:13:27 UTC (rev 3750)
+++ trunk/numpy/add_newdocs.py 2007-05-12 19:58:43 UTC (rev 3751)
@@ -332,7 +332,7 @@
add_newdoc('numpy.core.multiarray','set_numeric_ops',
"""set_numeric_ops(op=func, ...)
- Set some or all of the number methods for all array objects. Don't
+ Set some or all of the number methods for all array objects. Do not
forget **dict can be used as the argument list. Return the functions
that were replaced, which can be stored and set later.
@@ -810,7 +810,7 @@
"""a.getfield(dtype, offset) -> field of array as given type.
Returns a field of the given array as a certain type. A field is a view of
- the array's data with each itemsize determined by the given type and the
+ the array data with each itemsize determined by the given type and the
offset into the current array.
"""))
@@ -832,16 +832,38 @@
add_newdoc('numpy.core.multiarray', 'ndarray', ('mean',
- """a.mean(axis=None, dtype=None)
+ """a.mean(axis=None, dtype=None, out=None) -> mean
- Average the array over the given axis. If the axis is None,
- average over all dimensions of the array. Equivalent to
+ Returns the average of the array elements. The average is taken over the
+ flattened array by default, otherwise over the specified axis.
+
+ :Parameters:
+ axis : integer
+ Axis along which the means are computed. The default is
+ to compute the standard deviation of the flattened array.
+ dtype : type
+ Type to use in computing the means. For arrays of
+ integer type the default is float32, for arrays of float types it
+ is the same as the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must have
+ the same shape as the expected output but the type will be cast if
+ necessary.
- a.sum(axis, dtype) / size(a, axis).
+ :Returns:
+ mean : The return type varies, see above.
+ A new array holding the result is returned unless out is specified,
+ in which case a reference to out is returned.
- The optional dtype argument is the data type for intermediate
- calculations in the sum.
+ :SeeAlso:
+ - var : variance
+ - std : standard deviation
+ Notes
+ -----
+ The mean is the sum of the elements along the axis divided by the
+ number of elements.
+
"""))
@@ -1072,16 +1094,40 @@
add_newdoc('numpy.core.multiarray', 'ndarray', ('std',
"""a.std(axis=None, dtype=None, out=None) -> standard deviation.
- The standard deviation isa measure of the spread of a
- distribution.
+ Returns the standard deviation of the array elements, a measure of the
+ spread of a distribution. The standard deviation is computed for the
+ flattened array by default, otherwise over the specified axis.
- The standard deviation is the square root of the average of the
- squared deviations from the mean, i.e.
- std = sqrt(mean((x - x.mean())**2,axis=0)).
+ :Parameters:
+ axis : integer
+ Axis along which the standard deviation is computed. The default is
+ to compute the standard deviation of the flattened array.
+ dtype : type
+ Type to use in computing the standard deviation. For arrays of
+ integer type the default is float32, for arrays of float types it
+ is the same as the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must have
+ the same shape as the expected output but the type will be cast if
+ necessary.
- For multidimensional arrays, std is computed by default along the
- first axis.
+ :Returns:
+ standard deviation : The return type varies, see above.
+ A new array holding the result is returned unless out is specified,
+ in which case a reference to out is returned.
+ :SeeAlso:
+ - var : variance
+ - mean : average
+
+ Notes
+ -----
+
+ The standard deviation is the square root of the average of the squared
+ deviations from the mean, i.e. var = sqrt(mean((x - x.mean())**2)). The
+ computed standard deviation is biased, i.e., the mean is computed by
+ dividing by the number of elements, N, rather than by N-1.
+
"""))
@@ -1224,8 +1270,42 @@
add_newdoc('numpy.core.multiarray', 'ndarray', ('var',
- """a.var(axis=None, dtype=None)
+ """a.var(axis=None, dtype=None, out=None) -> variance
+ Returns the variance of the array elements, a measure of the spread of a
+ distribution. The variance is computed for the flattened array by default,
+ otherwise over the specified axis.
+
+ :Parameters:
+ axis : integer
+ Axis along which the variance is computed. The default is to
+ compute the variance of the flattened array.
+ dtype : type
+ Type to use in computing the variance. For arrays of integer type
+ the default is float32, for arrays of float types it is the same as
+ the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must have
+ the same shape as the expected output but the type will be cast if
+ necessary.
+
+ :Returns:
+ variance : The return type varies, see above.
+ A new array holding the result is returned unless out is specified,
+ in which case a reference to out is returned.
+
+ :SeeAlso:
+ - std : standard deviation
+ - mean: average
+
+ Notes
+ -----
+
+ The variance is the average of the squared deviations from the mean, i.e.
+ var = mean((x - x.mean())**2). The computed variance is biased, i.e.,
+ the mean is computed by dividing by the number of elements, N, rather
+ than by N-1.
+
"""))
Modified: trunk/numpy/core/defmatrix.py
===================================================================
--- trunk/numpy/core/defmatrix.py 2007-05-11 23:13:27 UTC (rev 3750)
+++ trunk/numpy/core/defmatrix.py 2007-05-12 19:58:43 UTC (rev 3751)
@@ -241,12 +241,121 @@
return N.ndarray.sum(self, axis, dtype, out)._align(axis)
def mean(self, axis=None, out=None):
+ """Compute the mean along the specified axis.
+
+ Returns the average of the array elements. The average is taken over
+ the flattened array by default, otherwise over the specified axis.
+
+ :Parameters:
+ axis : integer
+ Axis along which the means are computed. The default is
+ to compute the standard deviation of the flattened array.
+ dtype : type
+ Type to use in computing the means. For arrays of integer type
+ the default is float32, for arrays of float types it is the
+ same as the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must
+ have the same shape as the expected output but the type will be
+ cast if necessary.
+
+ :Returns:
+ mean : The return type varies, see above.
+ A new array holding the result is returned unless out is
+ specified, in which case a reference to out is returned.
+
+ :SeeAlso:
+ - var : variance
+ - std : standard deviation
+
+ Notes
+ -----
+ The mean is the sum of the elements along the axis divided by the
+ number of elements.
+
+ """
return N.ndarray.mean(self, axis, out)._align(axis)
def std(self, axis=None, dtype=None, out=None):
+ """Compute the standard deviation along the specified axis.
+
+ Returns the standard deviation of the array elements, a measure of the
+ spread of a distribution. The standard deviation is computed for the
+ flattened array by default, otherwise over the specified axis.
+
+ :Parameters:
+ axis : integer
+ Axis along which the standard deviation is computed. The
+ default is to compute the standard deviation of the flattened
+ array.
+ dtype : type
+ Type to use in computing the standard deviation. For arrays of
+ integer type the default is float32, for arrays of float types
+ it is the same as the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must
+ have the same shape as the expected output but the type will be
+ cast if necessary.
+
+ :Returns:
+ standard deviation : The return type varies, see above.
+ A new array holding the result is returned unless out is
+ specified, in which case a reference to out is returned.
+
+ :SeeAlso:
+ - var : variance
+ - mean : average
+
+ Notes
+ -----
+
+ The standard deviation is the square root of the average of the
+ squared deviations from the mean, i.e. var = sqrt(mean((x -
+ x.mean())**2)). The computed standard deviation is biased, i.e., the
+ mean is computed by dividing by the number of elements, N, rather
+ than by N-1.
+
+ """
return N.ndarray.std(self, axis, dtype, out)._align(axis)
def var(self, axis=None, dtype=None, out=None):
+ """Compute the variance along the specified axis.
+
+ Returns the variance of the array elements, a measure of the spread of
+ a distribution. The variance is computed for the flattened array by
+ default, otherwise over the specified axis.
+
+ :Parameters:
+ axis : integer
+ Axis along which the variance is computed. The default is to
+ compute the variance of the flattened array.
+ dtype : type
+ Type to use in computing the variance. For arrays of integer
+ type the default is float32, for arrays of float types it is
+ the same as the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must
+ have the same shape as the expected output but the type will be
+ cast if necessary.
+
+ :Returns:
+ variance : depends, see above
+ A new array holding the result is returned unless out is
+ specified, in which case a reference to out is returned.
+
+ :SeeAlso:
+ - std : standard deviation
+ - mean : average
+
+ Notes
+ -----
+
+ The variance is the average of the squared deviations from the mean,
+ i.e. var = mean((x - x.mean())**2). The computed variance is
+ biased, i.e., the mean is computed by dividing by the number of
+ elements, N, rather than by N-1.
+
+ """
return N.ndarray.var(self, axis, dtype, out)._align(axis)
def prod(self, axis=None, dtype=None, out=None):
Modified: trunk/numpy/core/fromnumeric.py
===================================================================
--- trunk/numpy/core/fromnumeric.py 2007-05-11 23:13:27 UTC (rev 3750)
+++ trunk/numpy/core/fromnumeric.py 2007-05-12 19:58:43 UTC (rev 3751)
@@ -691,12 +691,38 @@
around = round_
def mean(a, axis=None, dtype=None, out=None):
- """mean(a, axis=None, dtype=None)
- Return the arithmetic mean.
+ """Compute the mean along the specified axis.
- The mean is the sum of the elements divided by the number of elements.
+ Returns the average of the array elements. The average is taken over the
+ flattened array by default, otherwise over the specified axis.
- See also: average
+ :Parameters:
+ axis : integer
+ Axis along which the means are computed. The default is
+ to compute the standard deviation of the flattened array.
+ dtype : type
+ Type to use in computing the means. For arrays of
+ integer type the default is float32, for arrays of float types it
+ is the same as the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must have
+ the same shape as the expected output but the type will be cast if
+ necessary.
+
+ :Returns:
+ mean : The return type varies, see above.
+ A new array holding the result is returned unless out is specified,
+ in which case a reference to out is returned.
+
+ :SeeAlso:
+ - var : variance
+ - std : standard deviation
+
+ Notes
+ -----
+ The mean is the sum of the elements along the axis divided by the
+ number of elements.
+
"""
try:
mean = a.mean
@@ -704,14 +730,44 @@
return _wrapit(a, 'mean', axis, dtype, out)
return mean(axis, dtype, out)
+
def std(a, axis=None, dtype=None, out=None):
- """std(sample, axis=None, dtype=None)
- Return the standard deviation, a measure of the spread of a distribution.
+ """Compute the standard deviation along the specified axis.
- The standard deviation is the square root of the average of the squared
- deviations from the mean, i.e. std = sqrt(mean((x - x.mean())**2)).
+ Returns the standard deviation of the array elements, a measure of the
+ spread of a distribution. The standard deviation is computed for the
+ flattened array by default, otherwise over the specified axis.
- See also: var
+ :Parameters:
+ axis : integer
+ Axis along which the standard deviation is computed. The default is
+ to compute the standard deviation of the flattened array.
+ dtype : type
+ Type to use in computing the standard deviation. For arrays of
+ integer type the default is float32, for arrays of float types it
+ is the same as the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must have
+ the same shape as the expected output but the type will be cast if
+ necessary.
+
+ :Returns:
+ standard deviation : The return type varies, see above.
+ A new array holding the result is returned unless out is specified,
+ in which case a reference to out is returned.
+
+ :SeeAlso:
+ - var : variance
+ - mean : average
+
+ Notes
+ -----
+
+ The standard deviation is the square root of the average of the squared
+ deviations from the mean, i.e. var = sqrt(mean((x - x.mean())**2)). The
+ computed standard deviation is biased, i.e., the mean is computed by
+ dividing by the number of elements, N, rather than by N-1.
+
"""
try:
std = a.std
@@ -719,14 +775,44 @@
return _wrapit(a, 'std', axis, dtype, out)
return std(axis, dtype, out)
+
def var(a, axis=None, dtype=None, out=None):
- """var(sample, axis=None, dtype=None)
- Return the variance, a measure of the spread of a distribution.
+ """Compute the variance along the specified axis.
- The variance is the average of the squared deviations from the mean,
- i.e. var = mean((x - x.mean())**2).
+ Returns the variance of the array elements, a measure of the spread of a
+ distribution. The variance is computed for the flattened array by default,
+ otherwise over the specified axis.
- See also: std
+ :Parameters:
+ axis : integer
+ Axis along which the variance is computed. The default is to
+ compute the variance of the flattened array.
+ dtype : type
+ Type to use in computing the variance. For arrays of integer type
+ the default is float32, for arrays of float types it is the same as
+ the array type.
+ out : ndarray
+ Alternative output array in which to place the result. It must have
+ the same shape as the expected output but the type will be cast if
+ necessary.
+
+ :Returns:
+ variance : depends, see above
+ A new array holding the result is returned unless out is specified,
+ in which case a reference to out is returned.
+
+ :SeeAlso:
+ - std : standard deviation
+ - mean : average
+
+ Notes
+ -----
+
+ The variance is the average of the squared deviations from the mean, i.e.
+ var = mean((x - x.mean())**2). The computed variance is biased, i.e.,
+ the mean is computed by dividing by the number of elements, N, rather
+ than by N-1.
+
"""
try:
var = a.var
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