DOC: Clean up examples of low-level random access

Test examples on Linux and Windows
Correct bug in Cython example
Improve building instructions for numba examples

1 files changed, 14 insertions, 8 deletions

diff --git a/numpy/random/_examples/numba/extending_distributions.py b/numpy/random/_examples/numba/extending_distributions.py
index 9233ccced..7cf8bf0b0 100644
--- a/numpy/random/_examples/numba/extending_distributions.py
+++ b/numpy/random/_examples/numba/extending_distributions.py
@@ -1,22 +1,28 @@
 r"""
-On *nix, execute in randomgen/src/distributions
+Building the required library in this example requires a source distribution
+of NumPy or clone of the NumPy git repository since distributions.c is not
+included in binary distributions.
 
+On *nix, execute in numpy/random/src/distributions
+
+export ${PYTHON_VERSION}=3.8 # Python version
 export PYTHON_INCLUDE=#path to Python's include folder, usually \
     ${PYTHON_HOME}/include/python${PYTHON_VERSION}m
 export NUMPY_INCLUDE=#path to numpy's include folder, usually \
     ${PYTHON_HOME}/lib/python${PYTHON_VERSION}/site-packages/numpy/core/include
 gcc -shared -o libdistributions.so -fPIC distributions.c \
     -I${NUMPY_INCLUDE} -I${PYTHON_INCLUDE}
-mv libdistributions.so ../../examples/numba/
+mv libdistributions.so ../../_examples/numba/
 
 On Windows
 
-rem PYTHON_HOME is setup dependent, this is an example
+rem PYTHON_HOME and PYTHON_VERSION are setup dependent, this is an example
 set PYTHON_HOME=c:\Anaconda
+set PYTHON_VERSION=38
 cl.exe /LD .\distributions.c -DDLL_EXPORT \
     -I%PYTHON_HOME%\lib\site-packages\numpy\core\include \
-    -I%PYTHON_HOME%\include %PYTHON_HOME%\libs\python36.lib
-move distributions.dll ../../examples/numba/
+    -I%PYTHON_HOME%\include %PYTHON_HOME%\libs\python%PYTHON_VERSION%.lib
+move distributions.dll ../../_examples/numba/
 """
 import os
 
@@ -35,19 +41,19 @@ else:
     raise RuntimeError('Required DLL/so file was not found.')
 
 ffi.cdef("""
-double random_gauss_zig(void *bitgen_state);
+double random_standard_normal(void *bitgen_state);
 """)
 x = PCG64()
 xffi = x.cffi
 bit_generator = xffi.bit_generator
 
-random_gauss_zig = lib.random_gauss_zig
+random_standard_normal = lib.random_standard_normal
 
 
 def normals(n, bit_generator):
     out = np.empty(n)
     for i in range(n):
-        out[i] = random_gauss_zig(bit_generator)
+        out[i] = random_standard_normal(bit_generator)
     return out