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[Bug-gsl] Strange problem with gsl_eigen_hermv
From: |
Alexander Klein |
Subject: |
[Bug-gsl] Strange problem with gsl_eigen_hermv |
Date: |
Tue, 28 Dec 2004 14:26:49 +0100 |
Hello,
I spent the morning chasing a strange bug:
I've written a wrapper class in Smalltalk, so I can use the GSL from
Cincom VisualWorks.
Trying to compute the eigenvalues and -vectors of the 4*4 Hilbert
matrix from the GSL-manual, the Smalltalk version always came up with a
lot of NaNs instead of the correct result.
Checking with gdb, I found that the data passed to gsl_eigen_hermv was
definitely correct, but strangely enough, a C program that passed
exactly the same data ran without problems.
After some further experimentation, it turned out that the problem went
away after recompiling GSL with
setenv CFLAGS -O0
I use gcc 3.4.0 on a Pentium-IV running Suse Linux 9.0
The GSL-version is 1.5
Unfortunately, a sample program in Smalltalk is not really what you
would call a 'minimal example', so I won't send the whole class
definition here, but if there's any other information I can provide to
track the bug, I'll be glad to do so.
Thank you anyway for providing the GSL. It saves so much work!
Best regards,
Alex Klein
--
Alexander Klein, Diplom-Mathematiker
Lehrstuhl für Numerische Mathematik
Heinrich-Buff-Ring 44
35392 Giessen
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- [Bug-gsl] Strange problem with gsl_eigen_hermv,
Alexander Klein <=