Ben, You can use -pc_type redundant -redundant_pc_type lu to solve the linear system with a sequential LU to test if that improves the situation.
Likely your generation of the matrix on 2 processes is wrong, you can run with -mat_view on a small problem with both 1 and 2 processes and see if they are the same in both cases. I don't think what you propose to do below makes sense, Barry On Tue, 23 Jan 2007, Ben Tay wrote: > Hi, > > In my MPI CFD code, I have to solve 2 linear eqns - momentum and poisson > eqn. There's some error in the code and I don't know which one causes the > error. May I know if it is possible to solve 1 eqn in sequential mode while > the other in MPI to pinpoint the error since my code works ok in a > sequential mode. > > I tried to use this for one of the eqn: > > > call > MatCreateSeqAIJ(PETSC_COMM_SELF,size_x*size_y,size_x*size_y,9,PETSC_NULL_INTEGER,A_mat,ierr) > > call VecCreateSeq(PETSC_COMM_SELF,size_x*size_y,b_rhs,ierr) > > but there's error. > > Thank you. >
