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PARILUT preconditioner causes SEGFAULT

Posted: Thu Jul 12, 2018 1:32 am
by fedrat
Hello.
I am trying to use sparse MAGMA for solving dual elasticity+hydrodynamics problem, but met some difficulties. At the moment, system of linear equations is solved at CPU by BICGSTAB + ILUT, and i want to use same pair at GPU. But ILUT gives SEGFAULT upon calling magma_s_precondsetup. Moreover, i tried to launch testing_spreconditioner.cpp with next params "--solver BICGSTAB --precond PARILUT mat_ones.mtx", where mat_ones is 10x10 matrix with ones at diagonal. Got the same problem - SEGFAULT at magma_s_precondsetup.
I am using MAGMA 2.3.0 under Windows, GPU Quadro P5000 (capability 6.1).
Hope someone can help.
Thanks in advance.

Re: PARILUT preconditioner causes SEGFAULT

Posted: Fri Jul 13, 2018 2:42 am
by hartwig anzt
This is not a surprise. ParILUT is a threshold-ILU preconditioner. The ParILUT considers the level-fill as potential fill in candidates. But if you have a diagonal matrix, there is no level-fill, and there are no locations that are reasonable to consider as fill-in. Depending on your other test matrix, the same might happen.

I do however agree: MAGMA should not segfault, instead return without a preconditioner.

Thanks, Hartwig