[Insight-developers] VNL_CONFIG_ENABLE_SSE2=ON: Matrix-Vector multiplication fails...

[Hauke Heibel]

Hi there,

I just saw some vnl tests failing on my machine and after looking into 
it, it seems as if the multiplication fails. I assume that this has to 
do with SSE2 being enabled since otherwise tons of user must have 
stumbled over this issue.

Here are the tests (I ommited the ITK ones, since right now I assume 
they depend on the VNL ones) that failed.

1>  35 - vnl_test_cholesky (Failed)
1>  44 - vnl_test_ldl_cholesky (Failed)
1>  49 - vnl_test_qr (Failed)
1>  61 - vnl_test_svd (Failed)
1>  91 - vnl_test_quaternion (SEGFAULT)

I looked into the first one and it fails in test_cholesky.cxx lines 
40-47, where A*x = b is trying to be solved. I copied the random 
generated values into Matlab and tried to verify the individual steps 
and it looks as if line 43, b=A*x0 yields incorrect results. The 
archive, I have attached gives also evidence for this. The actual 
cholesky decomposition looks all right.

Any comments?

- Hauke

p.s. I am always confused, does it at all make sense to come here or 
should I've gone right away to the Mantis system... ???

-- 
Tim Hauke Heibel
Computer Aided Medical Procedures (CAMP)
fon: +49 89 289 19427
fax: +49 89 289 17059

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