[SciPy-user] problems with scipy.test() on Opteron 64-bit

Giovanni Samaey Giovanni.Samaey at cs.kuleuven.ac.be
Thu Nov 25 09:04:27 CST 2004


>
> Hmm, try also
>
> scipy.linalg.flapack.zgeev([[1,2,3],[1,2,3],[2,5,6]],0,0)
> scipy.linalg.flapack.dgeev(scipy.array([[1,2,3],[1,2,3],[2,5,6]],'d'),0,0) 
>
> scipy.linalg.flapack.dgeev(Numeric.array([[1,2,3],[1,2,3],[2,5,6]],'d'),0,0) 
>

The first one gives the correct result.  The second and third give the 
wrong result.

>
> If those fail as well then try a C program that uses dgeev to solve 
> the same eigenvalue problem:
>
> $ gcc main.c -llapack
> $ ./a.out
> wr=9.32183,-6.20979e-16,-0.321825,wi=0,0,0

I get (after adding some -lblas -lm and paths etc...)
./a.out
wr=9.43719,-0.115365,-0.321825,wi=0,0,0

which probably shows that the error comes from lapack.
(This is with the lapack I compiled myself in an intermediate step to 
build atlas for scipy.)
Just to repeat how I compiled lapack: I took the Makefile and added 
-fPIC and -m64 there
to give it the same compiler options as that atlas makefile.

Giovanni



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