Hi Barry, Thanks for your comments. To activate block low rank (BLR) approximation in MUMPS version 5.1.1, a user needs to turn on the functionality (i.e. ICNTL(35)=1) and specify the tolerance value (e.g. CNTL(7)=1e-4). In PETSC, I think that we can set up ICNTL and CNTL parameters for MUMPS. I was wondering if we can still use BLR approximation for a preconditioner for Krylov solvers.
Best, Evan On Sat, Sep 23, 2017 at 6:45 PM, Barry Smith <[email protected]> wrote: > > > On Sep 23, 2017, at 8:38 PM, Evan Um <[email protected]> wrote: > > > > Dear PETSC Users, > > > > My system matrix comes from finite element modeling and is complex and > unstructured. Its typical size is a few millions-by a few millions. I > wondering if I can use MUMPS parallel direct solver as a preconditioner in > PETSC. For example, I want to pass factored matrices to Krylov iterative > solvers such as QMR. Is there any PETSC+MUMPS example code for the purpose? > > You don't pass factored matrices you just pass the original matrix and > use -pc_type lu -pc_factor_mat_solver_package mumps > > > Can PETSC call the latest MUMPS that supports block low rank > approximation? > > No, send us info on it and we'll see if we can add an interface > > > > > > In advance, thank you very much for your comments. > > > > Best, > > Evan > > > > > > > > > > > >
