[petsc-users] mumps solve with same nonzero pattern

[Wen Jiang]

Hi,

I am using mumps in PETSc to solve a 0.2 million system on 128 cores.
Within Newton-Raphson iteration, the system with same sparse structure but
different values will be solved many times. And I specify the
preconditioning matrix having same nonzero pattern. The first time solving
costs around 900 seconds and later solving only takes around 200 seconds.
So I am wondering why the time differs that much. By setting the same
nonzero pattern of pc, which of the mumps control parameters does PETSc
change? Thanks.

Regards,
Wen
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