I would like to compare Python with Cython in term of time execution, so I wrote two files:
fac.py
def factorial(n):
if n >= 1:
return n*factorial(n - 1)
return 1
fastfac.pyx
cpdef long fastfactorial(long n):
if n>= 1:
return n*fastfactorial(n - 1)
return 1
Then I wrote a setup file:
setup.py
from distutils.core import setup
from Cython.Build import cythonize
setup(ext_modules = cythonize('fastfac.pyx'))
From the Powershell I executed the two commands:
pip install Cython
python setup.py build_ext --inplace
From the second command I get the following message:
Compiling fastfac.pyx because it changed.
[1/1] Cythonizing fastfac.pyx
C:\Users\.....\venv\lib\site-packages\Cython\Compiler\Main.py:369: FutureWarning: Cython directive 'language_level' not set, using 2 for now (Py2). This will change in a later release! File: C:\Users\.....\fastfac.pyx
tree = Parsing.p_module(s, pxd, full_module_name)
running build_ext
building 'fastfac' extension
error: Unable to find vcvarsall.bat
However I tried to make a comparison, so I wrote the file:
comparison.py
from fastfac import fastfactorial
from fac import factorial
from timeit import timeit
print(timeit('fastfactorial(20)', globals = globals(), number = 10000))
print(timeit('factorial(20)', globals = globals(), number = 10000))
When I run it, I get this error message:
Traceback (most recent call last):
File "C:/Users/...../comparison.py", line 1, in <module>
from fastfac import fastfactorial
ModuleNotFoundError: No module named 'fastfac'
It seems that in the file python.pyx the definition cpdef long fastfactorial(long n) is not recognized as a regular function definition but as a syntax error; in fact, if I try to run that file I get the error message:
File "C:/Users/...../fastfac.pyx", line 1
cpdef long fastfactorial(long n):
^
SyntaxError: invalid syntax
How can I solve? How can I correctly define a cpdef inside a .pyx file?
what am I missing?
