[petsc-users] Using Petsc with multiple RHS

[Barry Smith]

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
>