[petsc-users] Force running petsc sequentially

[Barry Smith]

On Sep 16, 2014, at 6:37 AM, Florian Lindner <mailinglists at xgm.de> wrote:

> Hello,
> 
> I'm currently replacing an RBF implementation with petsc linear algebra. The program itself runs parallel using MPI but the piece of code I work on runs strictly sequentially without making any use of MPI, just the same code on every node. Right now we're more interessted in patsc sparse matrix abilities then in its parallelization. Though parallelization is certainly interesting later....
> 
> What is the best way to run petsc sequentially?
> 
> 1) MatSetType the matrix to MATSEQSBAIJ e.g. -> expects MPI communicator of size 1.
> 2)  MatSetSizes(matrix, n, n, n, n) does not work.

    This should certainly work on one process

> 2) MatCreate not with PETSC_COMM_WORLD but with the communicator of size 1. Where do I get it from? (probably MPI_Comm_create and friends)

  Just use PETSC_COMM_SELF

> 
> Is there another more petsc like way?
> 
> Thanks,
> Florian