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Re: slowness of Schur decomposition in octave-2
From: |
Takafumi Hayashi |
Subject: |
Re: slowness of Schur decomposition in octave-2 |
Date: |
Mon, 07 Jul 1997 23:15:17 +0900 |
> If the reference time was produced with an Octave version build with
> G77, it would explain the bad result for the Schur decomposition. A
> few months ago i have tested the OS/2 version of the G77 and the most
> significant change was, that the Schur decomposition was 43 % slower
> (compared to the value for the Octave build with f2c). This was
> because the G77 uses static variables, while the f2c was configured
> to automatic variables. I've tried to change this, but when G77 also
> uses automatic variables, Octave crashes sometimes and on the other
> hand Octave is not faster than the with f2c compiled version. So i
> decided to uses f2c.
I forwarded this message to g77 list.
I got comments...
--------
This sounds like some sort of OS/2 lossage to me. Octave on my x86
GNU/Linux system doesn't try to compile anything with -fno-automatic
AFAICT and it passed all the tests (when I hacked configure
appropriately). I no longer have a compiled version to run, though.
address@hidden octave]$ find . -name Make\* |xargs grep no-automatic
address@hidden octave]$
Of course, if it did use -fno-automatic and g77 0.5.18, the slowness
is understandable.
--------
Regards,
---
Takafumi Hayashi address@hidden
The University of Aizu phone : +81-242-37-2614
FCS Lab. fax : +81-242-37-2734