[petsc-users] strumpack in ilu mode

[Barry Smith]

  Randy,

    Please take a look at https://gitlab.com/petsc/petsc/-/merge_requests/4543/ <https://gitlab.com/petsc/petsc/-/merge_requests/4543/> and try its branch. It has more features and may provide more of what you need.

  Barry


> On May 23, 2022, at 1:59 PM, Randall Mackie <rlmackie862 at gmail.com> wrote:
> 
> 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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