what communicator did you use with MatCreateSeqDense()? Try PETSC_COMM_SELF or MPI_COMM_SELF [and not PETSC_COMM_WORLD]
Satish On Tue, 30 Aug 2011, Likun Tan wrote: > Dear all, > > I am using MatCreateSeqDense() to create the matrix A, if i set np=2, i > got the error 'Comm must be of size 1'. As you suggested, i should put the > same dense matrix on every process, but how should i do it? > > And also, should the right hand side matrix B be partitioned by column? > > Thanks, > Likun > > > On Mon, August 29, 2011 6:01 pm, Jed Brown wrote: > > On Mon, Aug 29, 2011 at 16:49, Likun Tan <likunt at andrew.cmu.edu> wrote: > > > > > >> It is 27*27 with 343 non-zeros, i use LU for all the linear equations. > >> > > > > > > This is just too small and not sparse enough for sparse linear algebra to > > pay off. Create the same serial dense matrix redundantly on every > > process, factor it, put all your right hand sides for that process in a > > matrix B, and call MatMatSolve(). > > > > > > >
