[petsc-dev] PETSc LU vs SuperLU

[Dave Nystrom]

I have been comparing sequential SuperLU on one of my linear solves versus
PETSc LU.  I am finding SuperLU to be a little over 2x slower than PETSc LU.
I was wondering if this is due to SuperLU not being tuned to my problem or if
the PETSc LU algorithm performance is expected to be superior to that of
SuperLU in general.  I did play around with the reordering options for
SuperLU but did not find anything superior to the defaults.  I was also
wondering if building PETSc and its external packages with another compiler
such as PGI or Intel might result in higher performance in this regard.  Or
whether using a vendor blas like MKL would speed up SuperLU.  Or perhaps the
interface of SuperLU to PETSc results in some extra data copying that is the
difference.

Does anyone have any idea why SuperLU might be that much slower than PETSc
LU?

I also tried spooles and that was just a little slower than PETSc LU.  And I
tried MUMPS and that seg faulted after my problem had been running over an
hour.  This particular problem was running for less than 3 minutes with PETSc
LU.

I would be interested in any suggestions of things to try to speed up my LU
solve with either PETSc or any of the external packages.  Right now, I'm just
doing serial, single node calculations.

Thanks,

Dave