8000 DOCS: New ufunc creation docs by chrisjordansquire · Pull Request #132 · numpy/numpy · GitHub
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DOCS: New ufunc creation docs #132

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b7ea38b
DOCS: New ufunc creation docs
Aug 3, 2011
3fdc4cc
Changed to follow PEP 7
Aug 15, 2011
0a10f1a
ENH: Docs now Py3k compliant
Aug 15, 2011
2b16b97
style changes and bugs removed from docs
Aug 17, 2011
7f262fd
Py3K compliant, extra comments added
Aug 22, 2011
4adb151
npspam changed to npufunc
Aug 22, 2011
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Py3K compliant, extra comments added
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Chris Jordan-Squire committed Aug 22, 2011
commit 7f262fd044edde09168e7085826a1f98e13ab402
81 changes: 55 additions & 26 deletions doc/source/user/c-info.ufunc-tutorial.rst
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Expand Up @@ -139,7 +139,7 @@ the module.
/* This initiates the module using the above definitions. */
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Missed one ;)

#if PY_VERSION_HEX >= 0x03000000
static struct PyModuleDef moduledef = {
PyModuleDef HEAT_INIT,
PyModuleDef_HEAD_INIT,
"spam",
NULL,
-1,
Expand All @@ -150,7 +150,7 @@ the module.
NULL
};

PyObject *PyInit__npspam(void)
PyObject *PyInit_npspam(void)
{
PyObject *m;
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PyObject *m, *logit, *d;

m = PyModule_Create(&moduledef);
Expand Down Expand Up @@ -180,13 +180,18 @@ directory.

'''
setup.py file for spammodule.c

Calling
$python setup.py build
will build the extension library in a file
that looks like ./build/lib*, where lib* is
a file that begins with lib.
$python setup.py build_ext --inplace
will build the extension library in the current file.

Calling
$python setup.py build
will build a file that looks like ./build/lib*, where
lib* is a file that begins with lib. The library will
be in this file and end with a C library extension,
such as .so

Calling
$python setup.py install
will install the module in your site-packages file.
Expand All @@ -211,11 +216,25 @@ directory.
Once the spam module is imported into python, you can call logit
via spam.logit. Note that the function used above cannot be applied
as-is to numpy arrays. To do so we must call numpy.vectorize on it.
For example:
For example, if a python interpreter is opened in the file containing
the spam library or spam has been installed, one can perform the
following commands:

>>> import numpy as np
>>> import spam
>>> spam.logit(0)
-inf
>>> spam.logit(1)
inf
>>> spam.logit(0.5)
0.0
>>> x = np.linspace(0,1,10)
>>> spam.logit(x)
TypeError: only length-1 arrays can be converted to Python scalars
>>> f = np.vectorize(spam.logit)
>>> f(x)
array([ -inf, -2.07944154, -1.25276297, -0.69314718, -0.22314355,
0.22314355, 0.69314718, 1.25276297, 2.07944154, inf])

THE RESULTING LOGIT FUNCTION IS NOT FAST! numpy.vectorize simply
loops over spam.logit. The loop is done at the C level, but the numpy
Expand Down Expand Up @@ -305,7 +324,7 @@ the primary thing that must be changed to create your own ufunc.

#if PY_VERSION_HEX >= 0x03000000
static struct PyModuleDef moduledef = {
PyModuleDef HEAT_INIT,
PyModuleDef_HEAD_INIT,
"npspam",
NULL,
-1,
Expand All @@ -316,9 +335,9 @@ the primary thing that must be changed to create your own ufunc.
NULL
};

PyObject *PyInit__npspam(void)
PyObject *PyInit_npspam(void)
{
PyObject *m;
PyObject *m, *logit, *d;
m = PyModule_Create(&moduledef);
if (!m) {
return NULL;
Expand Down Expand Up @@ -375,11 +394,16 @@ or installed to site-packages via python setup.py install.
we use numpy.distutils instead of
distutils from the python standard library.

Calling
$python setup.py build_ext --inplace
will build the extension library in the current file.

Calling
$python setup.py build
will build the extension library in a file
that looks like ./build/lib*, where lib* is
a file that begins with lib.
$python setup.py build
will build a file that looks like ./build/lib*, where
lib* is a file that begins with lib. The library will
be in this file and end with a C library extension,
such as .so

Calling
$python setup.py install
Expand Down Expand Up @@ -579,7 +603,7 @@ the primary thing that must be changed to create your own ufunc.

#if PY_VERSION_HEX >= 0x03000000
static struct PyModuleDef moduledef = {
PyModuleDef HEAT_INIT,
PyModuleDef_HEAD_INIT,
"npspam",
NULL,
-1,
Expand All @@ -590,9 +614,9 @@ the primary thing that must be changed to create your own ufunc.
NULL
};

PyObject *PyInit__npspam(void)
PyObject *PyInit_npspam(void)
{
PyObject *m;
PyObject *m, *logit, *d;
m = PyModule_Create(&moduledef);
if (!m) {
return NULL;
Expand Down Expand Up @@ -648,12 +672,17 @@ or installed to site-packages via python setup.py install.
Note that since this is a numpy extension
we use numpy.distutils instead of
distutils from the python standard library.


Calling
$python setup.py build_ext --inplace
will build the extension library in the current file.

Calling
$python setup.py build
will build the extension library in a file
that looks like ./build/lib*, where lib* is
a file that begins with lib.
$python setup.py build
will build a file that looks like ./build/lib*, where
lib* is a file that begins with lib. The library will
be in this file and end with a C library extension,
such as .so

Calling
$python setup.py install
Expand Down Expand Up @@ -797,7 +826,7 @@ as well as all other properties of a ufunc.

#if PY_VERSION_HEX >= 0x03000000
static struct PyModuleDef moduledef = {
PyModuleDef HEAT_INIT,
PyModuleDef_HEAD_INIT,
"npspam",
NULL,
-1,
Expand All @@ -808,9 +837,9 @@ as well as all other properties of a ufunc.
NULL
};

PyObject *PyInit__npspam(void)
PyObject *PyInit_npspam(void)
{
PyObject *m;
PyObject *m, *logit, *d;
m = PyModule_Create(&moduledef);
if (!m) {
return NULL;
Expand Down
0