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ArnoldiSolver

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6 years 6 months ago - 6 years 6 months ago #227 by there
ArnoldiSolver was created by there
Hi:

I am using ArnoldiSolver to compute an eigenvalue problem, it gave eigenvalues around 1e+290. The following error showed up:

"Solve Hessenberg evp with Lapack ... error in eigensolver, info = 21".

I've tested several other eigenvalue problems using ArnoldiSolver and they worked well in those case.

I believe the input matrices are not the causes, since "scipy.sparse.linalg.eigs" gave correct eigenvalues (it is just very very slow...).

Best,
Shawn
Last edit: 6 years 6 months ago by there.
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6 years 6 months ago #228 by there
Replied by there on topic ArnoldiSolver
It's probably because I'm using mixed elements, where "CouplingType" has to be treated carefully?
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6 years 5 months ago - 6 years 5 months ago #237 by christopher
Replied by christopher on topic ArnoldiSolver
Hi Shawn,
Yes, this may be the case. Lapack is somehow trying to invert a singular matrix. Could you provide a small test case? I've just tried solving a mixed eigenvalue problem and it worked...

Best
Christopher
Last edit: 6 years 5 months ago by christopher.
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6 years 5 months ago #250 by there
Replied by there on topic ArnoldiSolver
Thank you very much Christopher. I think the ArnoldiSolver is working well. I realized the problem is possibly that I didn't update ngsolve to the latest version...

I currently have trouble updating ngsolve since I accidentally deleted mac-based-python2.7!
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