Annotating .py file with pxd for generating fast c-code. Needs Cython 0.19-dev, tested with both Python 2.7 and Python 3.3 Execute by running e.g.: bash run_python.sh bash run_cython_working.sh bash run_cython_not_working.sh

main.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
Mandelbrot example using cython
"""

# stdlib imports
import time

# external imports
import numpy as np
try:
    from PIL import Image
    use_pil = True
except ImportError:
    use_pil = False

# local imports
import mandel
import mapper

NX, NY, DIST, NS = 800, 800, 2.0, 40

t0 = time.time() # time execution
out = np.empty((NY, NX), dtype=np.float64)
mapper.map_mandel(out, NX, NY, NS, DIST)
print('Execution time: {}'.format(time.time() - t0))
print('Sum of matrix: {}'.format(np.sum(out)))

if use_pil:
    # Generate 256 level greyscale image of number of steps
    out *= 255.0
    img = Image.frombuffer('L', out.shape, out.astype(np.uint8), 'raw', 'L', 0, 1)
    img.save('out.png', "PNG")

mandel.pxd

import cython

cdef class MandelPoint:
    cdef double x, y

    @cython.locals(x=cython.double, y=cython.double, i=cython.int)
    cpdef steps_to_dist(self, double dist, int maxsteps)

mandel.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

class MandelPoint:

    __slots__ = ('x', 'y')

    def __init__(self, x, y):
        self.x = x
        self.y = y

    def steps_to_dist(self, dist, maxsteps):
        x = self.x
        y = self.y
        for i in range(maxsteps):
            if (x**2 + y**2)**0.5 > dist:
                break
            x = x**2 - y**2 + self.x
            y = 2*x*y + self.y
        return i

mapper.pxd

import cython
from mandel cimport MandelPoint
cimport numpy as np

@cython.locals(x=cython.double, y=cython.double, i=cython.int, j=cython.int)
cpdef map_mandel(np.ndarray[np.npy_float64, ndim = 2] out, int nx, int ny, int ns, double dist)

mapper.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from __future__ import division

from itertools import product
from mandel import MandelPoint

def map_mandel(out, nx, ny, ns, dist):
    """
    calc on grid with size 2*dist by 2*dist
    """
    for i, j in product(range(nx), range(ny)):
        x = (i - nx // 2) / (nx // 2) * dist
        y = (j - ny // 2) / (ny // 2) * dist
        out[j, i] = MandelPoint(x, y).steps_to_dist(dist, ns) / ns

run_cython_both.sh

#!/bin/bash
# Run script, using cython for "mandel.py+mandel.pxd"
# and "mapper.py+mapper.pxd" (_NOT_ working)

if [[ -f "mandel.c" ]]; then
    rm mandel.c
fi

if [[ -f "mapper.c" ]]; then
    rm mapper.c
fi

if [[ -f "setup.py" ]]; then
    rm setup.py
fi

cp setup.py_pxd_both setup.py
python setup.py build_ext --inplace
if [[ $? -eq 0 ]]; then
    mv mandel.py _mandel.py
    mv mapper.py _mapper.py
    python main.py
    mv _mandel.py mandel.py
    mv _mapper.py mapper.py
fi
if [[ $? -eq 0 && -f "out.png" ]]; then
    eog out.png
fi

run_cython_mandel.sh

#!/bin/bash
# Run script, using cython for "mandel.py+mandel.pxd" (working)
if [[ -f "mandel.c" ]]; then
    rm mandel.c
fi

if [[ -f "mapper.c" ]]; then
    rm mapper.c
fi

if [[ -f "setup.py" ]]; then
    rm setup.py
fi
cp setup.py_pxd_mandel setup.py
python setup.py build_ext --inplace
if [[ $? -eq 0 ]]; then
    mv mandel.py _mandel.py
    python main.py
    mv _mandel.py mandel.py
fi
if [[ $? -eq 0 && -f "out.png" ]]; then
    eog out.png
fi

run_python.sh

#!/bin/bash
# Run script, not using cython (working)
rm mandel.*so
rm mapper.*so
python main.py
if [[ $? -eq 0 && -f "out.png" ]]; then
    eog out.png
fi

setup.py_pxd_both

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

setup(ext_modules = [
    Extension('mandel', ['mandel.py', 'mandel.pxd']),
    Extension('mapper', ['mapper.py', 'mapper.pxd']),
    ],
    cmdclass = {'build_ext': build_ext}
)

setup.py_pxd_mandel

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

setup(ext_modules = [
    Extension('mandel', ['mandel.py', 'mandel.pxd']),
    ],
    cmdclass = {'build_ext': build_ext}
)