From help-octave-request at bevo dot che dot wisc dot edu Wed Feb 11 14:18:45 2004
Subject: for loop speed in different Windows versions
From: "Ben Diedrich" <Ben dot Diedrich at noaa dot gov>
To: help-octave at bevo dot che dot wisc dot edu
Date: Wed, 11 Feb 2004 14:11:33 -0600

I have encountered an interesting problem while trying out different
Octave packages for Windows and Cygwin. I have been using a precompiled
package (octave-2.1.50a-inst.exe) that I downloaded from the
Octave-Forge site (octave.sourceforge.net). This is a standalone package
that runs outside of Cygwin, although it uses its own tiny Cygwin setup.
It includes Octave-forge and Gnuplot, but not ATLAS. I decided to try
compiling Octave 2.1.50 from source, to have the ATLAS improvments and
multiple gnuplot windows in X.

I compiled and ran Octave successfully in Cygwin (including ATLAS BLAS,
octave-forge and gnuplot). I ran some speed checks that demonstrated
significant speed improvement from the ATLAS libraries using these
tests:
http://homepage.mac.com/chibaf/math/octave/octave_speed_up_by_atlas.html

The problem is that "for" loops seem to run ~6 times slower on my
self-compiled version vs the version I downloaded from
octave.sourceforge.net. I haven't tested anything else. I've tried
recompiling/reinstalling Octave with/without "--enable-shared",
"--disable-static", ATLAS, and "make install-strip". None improved the
situation. My system is Windows 2000 on a P4. Any ideas why this might
be happening?

Ben



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