diff options
Diffstat (limited to 'docs/src/tutorial/numpy.rst')
| -rw-r--r-- | docs/src/tutorial/numpy.rst | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/docs/src/tutorial/numpy.rst b/docs/src/tutorial/numpy.rst index 5fa205976..0a5535da6 100644 --- a/docs/src/tutorial/numpy.rst +++ b/docs/src/tutorial/numpy.rst @@ -28,7 +28,7 @@ systems, it will be :file:`yourmod.pyd`). We run a Python session to test both the Python version (imported from ``.py``-file) and the compiled Cython module. -.. sourcecode:: ipython +.. code-block:: ipythonconsole In [1]: import numpy as np In [2]: import convolve_py @@ -69,7 +69,7 @@ compatibility. Consider this code (*read the comments!*) : After building this and continuing my (very informal) benchmarks, I get: -.. sourcecode:: ipython +.. code-block:: ipythonconsole In [21]: import convolve2 In [22]: %timeit -n2 -r3 convolve2.naive_convolve(f, g) @@ -97,7 +97,7 @@ These are the needed changes:: Usage: -.. sourcecode:: ipython +.. code-block:: ipythonconsole In [18]: import convolve3 In [19]: %timeit -n3 -r100 convolve3.naive_convolve(f, g) @@ -143,7 +143,7 @@ if we try to actually use negative indices with this disabled. The function call overhead now starts to play a role, so we compare the latter two examples with larger N: -.. sourcecode:: ipython +.. code-block:: ipythonconsole In [11]: %timeit -n3 -r100 convolve4.naive_convolve(f, g) 3 loops, best of 100: 5.97 ms per loop @@ -170,6 +170,16 @@ function call.) The actual rules are a bit more complicated but the main message is clear: Do not use typed objects without knowing that they are not set to None. +What typing does not do +======================= + +The main purpose of typing things as :obj:`ndarray` is to allow efficient +indexing of single elements, and to speed up access to a small number of +attributes such as ``.shape``. Typing does not allow Cython to speed +up mathematical operations on the whole array (for example, adding two arrays +together). Typing does not allow Cython to speed up calls to Numpy global +functions or to methods of the array. + More generic code ================== |