On Wed, Apr 8, 2015 at 9:28 PM, Hong <hzh...@mcs.anl.gov> wrote: > David , > >> I'm curious about how to do a symmetric LDL^T factorization (instead of >> LU) with MUMPS and SuperLU. Based on this example: >> >> >> http://www.mcs.anl.gov/petsc/petsc-3.4/src/ksp/ksp/examples/tutorials/ex52.c.html >> >> my understanding is as follows: >> >> - With MUMPS I gather that we need to specify: >> >> MatSetOption(A,MAT_SPD,PETSC_TRUE); >> PCSetType(pc,PCCHOLESKY); >> >> I guess "-pc_type cholesky" on the command line is equivalent to the >> PCSetType call, right? Is specifying MAT_SPD required in order for MUMPS to >> do an LDL^T factorization? >> > Mumps supports Cholesky factorization for symmetric, and symmetric+spd > matrices. You may consult mumps user manual. >
OK, thanks. But I was also wondering about the PETSc interface to MUMPS. I consulted the MUMPS manual, but it just says that you need to specify "SYM=1" in order to get an LDL^T factorization. I gather that if we set MatSetOption(A,MAT_SPD,PETSC_TRUE); in PETSc then that will tell MUMPS to use SYM=1, right? Thanks, David