Red Hat Bugzilla – Bug 138685
gcc miscompiles numerical code (lapack)
Last modified: 2007-11-30 17:10:54 EST
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Description of problem:
It appears that gcc in FC3 miscompiles numerical code.
The problem appears to be with lapack libraries and can be
demonstrated with octave (which uses them):
[dima@localhost ~]$ octave
GNU Octave, version 2.1.57 (i686-pc-linux-gnu).
Copyright (C) 2004 John W. Eaton.
octave:2> tic; eig(a); toc
error: dgeev failed to converge
Sometimes it just hangs there for few minutes after which I kill it.
I tried to compile octave myseelf agains ATLAS (different, optimized
blas/lapack implementation) libraries, which I compile myself as well.
The result was the same. I also tried different versions of octave.
This al works on RHEL3, RH9, FC2, FC1.
It is possible that the problem is actually with glibc. I was not able
to recompile octave with gcc33 to check that.
Version-Release number of selected component (if applicable):
gcc version 3.4.2 20041017 (Red Hat 3.4.2-6.fc3)
Steps to Reproduce:
1. start octave
2. type at the octave prompt as shown
Actual Results: octave hangs or gives an error
Expected Results: "0.004" (may vary slightly) -- this is 4 msec that
it took the code to run on FC2.
this is on athlon/xp 2000MHz/500Meg.
*** This bug has been marked as a duplicate of 138683 ***