Hello, I used to use MUMPS directly with sparse multiple RHS. Now I use MUMPS through PETSc interface and solution for multiple RHS takes 1.5-2 times longer (MatMatSolve). My first question is whether do you use multiple RHS internally or you solve one-by-one? Second guess concerns the option: ICNTL(20) (rhs sparse pattern): 0
It's always switched off in PETSc, however my RHS are very sparse (8-32 nonzeros ans my system is 10^6). I can imagine that ignoring sparsity makes this performance difference. Any ideas are appreciated. Regards, Alexander
