Renting CPU time for a Python script

[Andreas Kostyrka]

Am Sam, 2002-07-20 um 22.16 schrieb Zachary Bortolot:
> Hi Fernando,
> 
> Thanks for your very informative post!  Unfortunately the bottleneck
> in my program lies with the PIL extension since I have to perform a
> lot of putpixel and getpixel operations, which are quite expensive in
Well, there are certain Python optimizations you could try:
instead of an inner loop like this:
for i in xrange(100):
  img.putpixel((i,i),1)

use this:

pp=img.putpixel
for i in xrange(100):
  pp((i,i),1)

Basically python function calls are painful slow for things like
putpixel. Try to move more data per call.
Either get your data into python with img.getdata (if I recall
correctly) split it up into a list and manipulate it in python, or
manipulate the data directly in C.

Best regards,

Andreas Kostyrka