using MUMPS with mg

[Thomas Geenen]

dear Petsc users,

when using mg with Petsc (ml to be precise)
the default solver on the coarsest level is "redundant"
(I could not find much info in either the usermanual or de online
manuals about this solver)

it seems to be a sequential LU factorization running on all cpu's at
the same time?
doing the same thing?

i try to use MUMPS instead.
i try to invoke mumps by calling
ierr = PetscOptionsSetValue("-mg_coarse_ksp_type", "preonly");
ierr = PetscOptionsSetValue("-mg_coarse_mat_type", "aijmumps");
ierr = PetscOptionsSetValue("-mg_coarse_pc_type", "lu");

this gives me

[0]PETSC ERROR: --------------------- Error Message
------------------------------------
[0]PETSC ERROR: No support for this operation for this object type!
[0]PETSC ERROR: Matrix type mpiaij  symbolic

so apparently Petsc did not convert the matrix on the coarsest level.
if i remove the pc_type the conversion option is ignored and Petsc
uses redundant.



cheers
Thomas