From help-request at octave dot org Thu Oct  6 16:10:08 2005
Subject: Re: BLAS lib performance (was Re: MPI (was Re: BIG libraries ....))
From: Quentin Spencer <qspencer at ieee dot org>
To: Fredrik Lingvall <fl at ifi dot uio dot no>
CC: help at octave dot org
Date: Thu, 06 Oct 2005 16:07:21 -0500

Fredrik Lingvall wrote:

> I noticed that matlab utilizes that B=A*A'  (and A'*A) is symmetric 
> (A*A' only takes
> half the time to compute compared to A*A). Is this functionality 
> available in octave as well?


I haven't looked at the source code, but I think Octave doesn't do this 
automatically. I was recently comparing Octave with ATLAS libraries to 
Matlab, and I discovered that in Octave, Z=X*Y takes the same amount of 
time as Z=X*X', while in Matlab, the second is faster than the first.

-Quentin



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