From bug-request at octave dot org Thu Jan 12 11:33:10 2006
Subject: Re: Compiling octave with Intel C++/Fortran compilers on Linux
From: "Tetsuji \"Maverick\" Rai" <maverick31337 at gmail dot com>
To: Shai Ayal <shaia at biocontrol dot co dot il>
CC: bug at octave dot org
Date: Thu, 12 Jan 2006 09:45:02 -0600

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Sorry, I don't know how to benchmark octave (I'm an octave newbie), but
usually seti at home compiled with icc with most aggressively (least
accurate) options is 2-3 times as fast as gcc-3.x on Linux with sse3
enabled P4.  As for accuracy, I test ieee compliance with the latest
version of

http://www.rtems.com/cgi-bin/viewcvs.cgi/rtems/testsuites/samples/paranoia/paranoia.c

gcc with -O(1-3) gives "flawed" or "unacceptable" results even with
- -mieee-fp flag, while icc always gives "satisfactory" or "acceptable"
results with -mp (ieee-compliant) flag even if it's optimized with sse3.

So I personally like Intel compiler (and it's free for Linux).

- -Tetsuji

Shai Ayal wrote:
> Can you show some results which show it is faster and probably more
> accurate ?
> 
> Shai
> 
> Tetsuji "Maverick" Rai wrote:
> Hi,
> 
> I've successfully compiled octave with Intel C++/Fortran compiler on
> Gentoo Linux on P4 to make it faster and probably more accurate (because
> it's more accurate than gcc-3.4.4 with proper options.)  But I needed a
> tweak, so I write diff here.
> 
> It's in src/oct-stream.cc, and the diff for 2.1.72 is
> ...snip.....
> 
> regards,
> 
> 
- --
Tetsuji 'Maverick' Rai
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