Non-orthogonal eigenvectors with DSBGVX

Open discussion regarding features, bugs, issues, vendors, etc.

Non-orthogonal eigenvectors with DSBGVX

Postby bradders2421 » Mon Nov 09, 2015 5:30 am

I have a problem when calculating the eigenvectors of a 148x148 symmetric band matrix that two of the four eigenvectors calculated are clearly not orhtogonal. DSBGVX is being called with RANGE='I'. This occurs in version 3.4.2 of BLAS and LAPACK built with optimisations turned off in Visual Studio on Windows. When I set all small values (e.g. all values < machine precision * value of largest element) to zero, the problem goes away. Therefore, I suspect this is to do with some major loss of precision.

Do you think that this could be the same as bugs 56 and/or 126?

Many thanks
bradders2421
 
Posts: 1
Joined: Fri Nov 06, 2015 12:37 pm

Return to User Discussion

Who is online

Users browsing this forum: No registered users and 1 guest