[petsc-users] strumpack in ilu mode

[Randall Mackie]

Dear PETSc team:

I am trying to use Strumpack in ILU mode, which is suppose to activate it’s low rank approximation as described on the man page:

https://petsc.org/release/docs/manualpages/Mat/MATSOLVERSSTRUMPACK.html <https://petsc.org/release/docs/manualpages/Mat/MATSOLVERSSTRUMPACK.html>

and in this exchange a few years ago:

https://lists.mcs.anl.gov/pipermail/petsc-users/2017-October/033560.html <https://lists.mcs.anl.gov/pipermail/petsc-users/2017-October/033560.html>


However, regardless of whether I specify ILU or LU, the behavior is the same, and the solution is in 1 step, meaning (to me) it’s doing the LU direct solve.
Furthermore, when I set verbose mode, it doesn’t seem to be activating low rank mode (that is, there are HSS or BLR frontal matrices created).


I’m running this example:

https://petsc.org/release/src/ksp/ksp/tutorials/ex2.c.html <https://petsc.org/release/src/ksp/ksp/tutorials/ex2.c.html>

using options:

mpiexec -n 4 ./ex2 -pc_type ilu -pc_factor_mat_solver_package strumpack

I’m likely doing something wrong, but I can’t figure out what, and would appreciate advice on how to use the strumpack ILU mode.

Thanks, Randy M.


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