[Trilinos-Users] [EXTERNAL] Anasazi solver with ML preconditioner won't converge

[Andris Freimanis]

Heidi and Alicia,

yes the M was singular in BCSST[K/M]01.

I tried LOBPCG with both Ifpack and ML preconditioners for BCSST[K/M]08 
matrices, but solver didn't converge in both cases. I attached output 
from both solves and source files.

Additionally copy+pasted, compiled and ran 
"LOBPCGEpetraExGenPrecIfpack.cpp" and 
"BlockDavidsonEpetraExGenPrecIfpack.cpp". They didn't converge for 
problems built in those files, could this indicate some kind of a 
problem with my trilinos installation?


On 2017.02.07. 03:19, Thornquist, Heidi K wrote:
> Good point Alicia, I didn't pay enough attention to bcsstm01, that can
> easily cause problems!
>
> Andris, if M is indeed non-singular (it seems to be a diagonal in the spy
> plot), would you mind trying this again with a generalized eigenproblem
> that has a positive definite mass matrix?  For example, bcsst[k/m][6,8,9]?
>   However, it may be easier to modify an example like
> anasazi/epetra/example/BlockDavidson/BlockDavidsonEpetraExGenPrecIfpack.cpp
>   or anasazi/epetra/example/LOBPCG/LOBPCGEpetraExGenPrecIfpack.cpp.  These
> examples use a simple incomplete Cholesky preconditioner and will converge
> to the solution with their current settings if the eigensolver sorts for
> the smallest magnitude (--sort="SM").  Changing just the preconditioner,
> from Ifpack to ML, will give you an easy problem to try it out on.
>
> Thanks,
> Heidi
>

-- 
Andris Freimanis
PhD student

Riga Technical university
Institute of transporation
engineering

Ķīpsalas iela 6a, Rīga
00371 263 823 52
andris.freimanis_1 at edu.rtu.lv
www.rtu.lv

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