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DGMRES gone?

Posted: Mon Jul 13, 2015 1:10 pm
by JosefWeinbub
Hi,
Just to verify: In 1.6.2 dgmres is gone? The declaration is there (sparse-iter/include/magmasparse_d.h) but the implementation is gone.
There is a 'dfgmres' version, is this one replacing dgmres or will dgmres come back in a future release?
Best, Josef

Re: DGMRES gone?

Posted: Mon Jul 13, 2015 3:58 pm
by hartwig anzt
Dear Josef,

you are right, dgmres is still listed in the header, but does no longer exist. dfgmres is a flexible GMRES implementation, this allows for changing preconditioners. If you want a plain (unpreconditioned) GMRES, using dfgmres without preconditioner is almost equivalent. The performance differences are also negligible, as the cost of the additional copy in every iteration is small compared to the SpMV and the orthogonalization.
The purpose of removing was keeping the maintenance effort low. If you however need the original GMRES according to Saad's book, please let me know, and we will put it back in the next release.

Thanks, Hartwig

Re: DGMRES gone?

Posted: Tue Jul 14, 2015 5:01 am
by JosefWeinbub
Hi Hartwig!

Thank you very much for your quick reply.
1.6.1 still has the GMRES implementation, that serves the purpose.

Best, Josef