Re: [Numpy-discussion] Multithreading support

2010-02-14 Thread Chris Colbert
Perhaps it's my inability to properly use openmp, but when working on scikits.image on algorithms doing per-pixel manipulation with numpy arrays (using Cython), i saw better performance using Python threads and releasing the GIL than I did with openmp. I found the openmp overhead to be quite

[Numpy-discussion] Multithreading support

2010-02-13 Thread Wolfgang Kerzendorf
Dear all, I don't know much about parallel programming so I don't know how easy it is to do that: When doing simple arrray operations like adding two arrays or adding a number to the array, is numpy able to put this on multiple cores? I have tried it but it doesnt seem to do that. Is there a

Re: [Numpy-discussion] Multithreading support

2010-02-13 Thread David Cournapeau
On Sat, Feb 13, 2010 at 6:20 PM, Wolfgang Kerzendorf wkerzend...@googlemail.com wrote: Dear all, I don't know much about parallel programming so I don't know how easy it is to do that: When doing simple arrray operations like adding two arrays or adding a number to the array, is numpy able

Re: [Numpy-discussion] Multithreading support

2010-02-13 Thread René Dudfield
hi, see: http://numcorepy.blogspot.com/ They see a benefit when working with large arrays. Otherwise you are limited by memory - and the extra cores don't help with memory bandwidth. cheers, On Sat, Feb 13, 2010 at 2:20 PM, David Cournapeau courn...@gmail.comwrote: On Sat, Feb 13, 2010 at