On Dec 11, 2011, at 9:29 AM, Alexander Grayver wrote: > 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?
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. We do not handle a sparse right hand side. > > Regards, > Alexander >
