Gael Varoquaux wrote: > I tried tweak my Cython code for performance by manually inlining a small > function, and ended up with a less performant code. I must confess I > don't really understand what is going on here. If somebody has an > explaination, I'd be delighted. The code follows. > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > from numpy import zeros > > # Make sure numpy is initialized. > include "c_numpy.pxd" > > ############################################################################## > cdef int inner_loop(float c_x, float c_y): > cdef float x, y, x_buffer > x = 0; y = 0 > cdef int i > for i in range(50): > x_buffer = x*x - y*y + c_x > y = 2*x*y + c_y > x = x_buffer > if (x*x + x*y > 100):
The line above looks like a typo, and does not match your inline version. Could that be making the difference? Eric > return 50 - i > > def do_Mandelbrot_cython(): > cdef ndarray threshold_time > threshold_time = zeros((500, 500)) > cdef double *tp > cdef float c_x, c_y > cdef int i, j > c_x = -1.5 > tp = <double*>threshold_time.data > for i in range(500): > c_y = -1 > for j in range(500): > tp += 1 > c_y += 0.004 > tp[0] = inner_loop(c_x, c_y) > c_x += 0.004 > return threshold_time > > > def do_Mandelbrot_cython2(): > cdef ndarray threshold_time > threshold_time = zeros((500, 500)) > cdef double *tp > tp = <double*>threshold_time.data > cdef float x, y, xbuffer, c_x, c_y > cdef int i, j, n > c_x = -1.5 > for i in range(500): > c_y = -1 > for j in range(500): > tp += 1 > c_y += 0.004 > x = 0; y = 0 > for n in range(50): > x_buffer = x*x - y*y + c_x > y = 2*x*y + c_y > x = x_buffer > if (x*x + y*y > 100): > tp[0] = 50 -n > break > c_x += 0.004 > return threshold_time > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > And the timing I get are: > > In [2]: %timeit C.do_Mandelbrot_cython2() > 10 loops, best of 3: 342 ms per loop > > In [3]: %timeit C.do_Mandelbrot_cython() > 10 loops, best of 3: 126 ms per loop > > Cheers, > > Gaël > _______________________________________________ > Numpy-discussion mailing list > [EMAIL PROTECTED] > http://projects.scipy.org/mailman/listinfo/numpy-discussion _______________________________________________ Cython-dev mailing list [email protected] http://codespeak.net/mailman/listinfo/cython-dev
