From help-octave-request at bevo dot che dot wisc dot edu Tue Jan 14 21:11:54 2003 Subject: Re: multi-threaded octave? From: Paul Kienzle To: Shahbaz Chaudhary Cc: help-octave at bevo dot che dot wisc dot edu Date: Tue, 14 Jan 2003 22:10:28 -0500 Shahbaz Chaudhary wrote: >Hi, I just installed Octave and it works great. But as I was running a >particularly long computation, I noticed that it was only using one of >my cpus (my computer has two). Apparently it is single threaded...is >there a multi-threaded version of the program? > No. >Actually I installed octave (and every thing it depended on) using >redhat RPMs (for my RH 7.3) system. Later I found out about >ATLAS...while I was installing that it asked my about multiple threads. >Once I had configured and installed atlas, I ran my octave session >again, but didn't see any difference...I'm not sure if that is because >my pre-existing octave didn't even pickup the newly installed atlas. > If you are not seeing any performance gain on matrix multiplication for larger matrices (e.g., x=rand(100); tic; y=x*x; toc) then you aren't linking against atlas. You may need to reconfigure and recompile octave from sources. >Any way, if there is something I can do to improve performance >(especially since one of my cpus is going to waste), I'll appreciate it. > Serial code will be slow. Try to get rid of for loops whereever they occur. Make sure you preallocate matrices rather than extending them. Once you have your algorithm developed, convert the remaining for loops into C++. >BTW, if I run octave on Apple's g4...will their vector technology >significantly speed up octave? Thanks. > If you have vendor blas which can make use of it then it may. Altas is competitive with vendor blas in a lot of cases, so you may see no gain. Paul Kienzle pkienzle at users dot sf dot net ------------------------------------------------------------- Octave is freely available under the terms of the GNU GPL. Octave's home on the web: http://www.octave.org How to fund new projects: http://www.octave.org/funding.html Subscription information: http://www.octave.org/archive.html -------------------------------------------------------------