Hi Nikhil, Typically, you would grab the "raw" underlying Mat object and do the PETSc call yourself. This would be accessible from the libMesh::PetscMatrix object. Typically the ImplicitSystem has the system matrix, but I'm not familiar with where these matrices would be cached on the RB side of things. I would use the Oxygen documentation as a starting point: libmesh.github.io (although it seems GitHub is misbehaving ATM). I hope that helps.
Best, Paul On Thu, Apr 23, 2020 at 12:06 AM Nikhil Vaidya <nikhilvaidy...@gmail.com> wrote: > Hi, > > I am using reduced basis for my work. The number of Aq matrices in my > problem is very large (~250). Because of this, the memory requirements of > my program are ~200 times the mesh-file size. I did some memory usage study > and found out that the allocate_data_structures() function in > RBConstruction is responsible for most of the memory usage. > > I think this might be due to the large number of Petsc sparse matrices > being constructed. Each Aq matrix is known to have non-zero entries > corresponding to only a small sub-domain of the geometry. All these > sub-domains are separate blocks in the mesh. I get the feeling that for > each sparse matrix memory is being allocated even for the zero entries. I > saw that Petsc has an option MAT_IGNORE_ZERO_ENTRIES. How does one pass > this in libMesh? Please note that I am not using libMesh directly. My code > is a MOOSE app, and I am using the RB functionality of the underlying > libmesh code. > > Best regards, > Nikhil > > _______________________________________________ > Libmesh-users mailing list > Libmesh-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/libmesh-users > _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
