On Wed, Apr 8, 2015 at 11:06 PM, Hong <[email protected]> wrote: > David: > >> >>>> 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? >> > > When user requests Cholesky factorization, PETSc sets "SYM=2" as default; > If user sets flag of spd, then the interface uses "SYM=1" in order to get > an LDL^T factorization. See MatGetFactor_xxx_mumps() in > petsc/src/mat/impls/aij/mpi/mumps/mumps.c: > > ... > B->factortype = MAT_FACTOR_CHOLESKY; > if (A->spd_set && A->spd) mumps->sym = 1; > else mumps->sym = 2; > ... >
OK, got it, thanks! David
