Questions regarding MatCreateMPIAIJWithArrays

[Mads Fredrik Skoge Hoel]

Hi,

I am in a similar situation as Tim. I am starting out with a sequential
program using PETSc as a solver and this other library to discretisize.
Which hopefully will become a parallel program once run under mpirun.

But calling MatCreateMPIAIJWithArrays i get the error message:
[0]PETSC ERROR: --------------------- Error Message
------------------------------------
[0]PETSC ERROR: Object is in wrong state!
[0]PETSC ERROR: Must call MatSetSizes() first!
[0]PETSC ERROR:
------------------------------------------------------------------------

This is the call generating the error message:
MatCreateMPIAIJWithArrays(PETSC_COMM_WORLD, n, m, n, m, irow, jcol,
&dpA(1), &A);

I am probably using the MatCreateMPIAIJWithArrays function wrong or in a
wrong context.

Is it allowed to call MatCreateMPIAIJWithArrays when running as a
uniprocessor application? Or must I use in a multiprocessor context
calling MatCreateSeqAIJWithArrays on each processor? And how would a PETSc
solver know that local Mat A is part of a global matrix?

Any help is highly appreciated.

Regards,
Mads