Let's see a Python method which takes care of calculating all prime numbers within a range (calculate_primes.py).

def calculate_primes(limit): primes = [] number = 0 divisor = 0 for number in range(limit): for divisor in range(2, number+1): if number % divisor == 0 and number == divisor: primes.append(number) break elif number % divisor == 0 and number != divisor: break return primes

Now let's import this module in another program and run it in order to work out the time spent in searching for all prime numbers between 2 and 10000 (the application will be executed five times and averaged it).

$ cat test.py from timeit import Timer timer = Timer("calculate_primes(10000)", "from calculate_primes import calculate_primes") print sum(timer.repeat(repeat=5, number=1)) / 5 $ python test.py 1.7978372097

The next step will be to compile this program with Cython in order to generate C extensions for our program. So as to install Cython, you have a couple of options: either to grab directly its source code from the web page of the project, or install it from some repository. In my case, I am going to download its source code and thereby, to be able to have the most recent version (0.18 at present).

After downloading and uncompressing it, you will be able to install it on your system by running the setup.py script, or as in my case, just decompressing it on the home directory and using that path later. Also point out that you must have installed on your system all tools needed to compile C/C++ programs (for example, the package build-essential in case of Ubuntu).

$ mkdir cython ; cd cython cython$ wget http://cython.org/release/Cython-0.18.zip ; unzip Cython-0.18.zip

The first test will be to compile the module called calculate_primes with Cython, so as to generate on the one hand a C file, and on the other, a module loadable by Python. First up, you need to change the extension of the module from py to pyx. And to compile it, you might do it by hand, but it is much better to create a tiny script responsible of accomplishing it.

cython$ cp -a calculate_primes.py calculate_primes1.pyx cython$ cat setup.py import sys sys.path.insert(0, "/home/javi/cython/Cython-0.18") from distutils.core import setup from distutils.extension import Extension from Cython.Distutils import build_ext setup( cmdclass = {'build_ext': build_ext}, ext_modules = [Extension("calculate_primes1", ["calculate_primes1.pyx"])] )

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