1: static char help[] = "Tests MatMeshToDual()\n\n";

  3: /*
  4:   Include "petscmat.h" so that we can use matrices.
  5:   automatically includes:
  6:      petscsys.h       - base PETSc routines   petscvec.h    - vectors
  7:      petscmat.h    - matrices
  8:      petscis.h     - index sets            petscviewer.h - viewers
  9: */
 10: #include <petscmat.h>

 12: int main(int argc, char **args)
 13: {
 14:   Mat             mesh, dual;
 15:   PetscInt        Nvertices = 6; /* total number of vertices */
 16:   PetscInt        ncells    = 2; /* number cells on this process */
 17:   PetscInt       *ii, *jj;
 18:   PetscMPIInt     size, rank;
 19:   MatPartitioning part;
 20:   IS              is;

 22:   PetscFunctionBeginUser;
 23:   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
 24:   PetscCallMPI(MPI_Comm_size(MPI_COMM_WORLD, &size));
 25:   PetscCheck(size == 2, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This example is for exactly two processes");
 26:   PetscCallMPI(MPI_Comm_rank(MPI_COMM_WORLD, &rank));

 28:   PetscCall(PetscMalloc1(3, &ii));
 29:   PetscCall(PetscMalloc1(6, &jj));
 30:   ii[0] = 0;
 31:   ii[1] = 3;
 32:   ii[2] = 6;
 33:   if (rank == 0) {
 34:     jj[0] = 0;
 35:     jj[1] = 1;
 36:     jj[2] = 2;
 37:     jj[3] = 1;
 38:     jj[4] = 2;
 39:     jj[5] = 3;
 40:   } else {
 41:     jj[0] = 1;
 42:     jj[1] = 4;
 43:     jj[2] = 5;
 44:     jj[3] = 1;
 45:     jj[4] = 3;
 46:     jj[5] = 5;
 47:   }
 48:   PetscCall(MatCreateMPIAdj(MPI_COMM_WORLD, ncells, Nvertices, ii, jj, NULL, &mesh));
 49:   PetscCall(MatMeshToCellGraph(mesh, 2, &dual));
 50:   PetscCall(MatView(dual, PETSC_VIEWER_STDOUT_WORLD));

 52:   PetscCall(MatPartitioningCreate(MPI_COMM_WORLD, &part));
 53:   PetscCall(MatPartitioningSetAdjacency(part, dual));
 54:   PetscCall(MatPartitioningSetFromOptions(part));
 55:   PetscCall(MatPartitioningApply(part, &is));
 56:   PetscCall(ISView(is, PETSC_VIEWER_STDOUT_WORLD));
 57:   PetscCall(ISDestroy(&is));
 58:   PetscCall(MatPartitioningDestroy(&part));

 60:   PetscCall(MatDestroy(&mesh));
 61:   PetscCall(MatDestroy(&dual));
 62:   PetscCall(PetscFinalize());
 63:   return 0;
 64: }

 66: /*TEST

 68:    build:
 69:      requires: parmetis

 71:    test:
 72:       nsize: 2
 73:       requires: parmetis

 75: TEST*/