xref: /petsc/src/mat/tests/ex98.c (revision 732aec7a18f2199fb53bb9a2f3aef439a834ce31)

static char help[] = "Tests MatMPIAIJSetPreallocationCSR()\n\n";

/*
  Include "petscmat.h" so that we can use matrices.  Note that this file
  automatically includes:
     petscsys.h       - base PETSc routines   petscvec.h - vectors
     petscmat.h - matrices
     petscis.h     - index sets
     petscviewer.h - viewers
*/
#include <petscmat.h>

int main(int argc, char **args)
{
  Mat         A;
  PetscInt   *ia, *ja;
  PetscMPIInt rank, size;

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &args, NULL, help));
  PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
  PetscCheck(size == 4, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Must run with 4 processors");
  PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));

  PetscCall(PetscMalloc1(5, &ia));
  PetscCall(PetscMalloc1(16, &ja));
  if (rank == 0) {
    ja[0] = 1;
    ja[1] = 4;
    ja[2] = 0;
    ja[3] = 2;
    ja[4] = 5;
    ja[5] = 1;
    ja[6] = 3;
    ja[7] = 6;
    ja[8] = 2;
    ja[9] = 7;
    ia[0] = 0;
    ia[1] = 2;
    ia[2] = 5;
    ia[3] = 8;
    ia[4] = 10;
  } else if (rank == 1) {
    ja[0]  = 0;
    ja[1]  = 5;
    ja[2]  = 8;
    ja[3]  = 1;
    ja[4]  = 4;
    ja[5]  = 6;
    ja[6]  = 9;
    ja[7]  = 2;
    ja[8]  = 5;
    ja[9]  = 7;
    ja[10] = 10;
    ja[11] = 3;
    ja[12] = 6;
    ja[13] = 11;
    ia[0]  = 0;
    ia[1]  = 3;
    ia[2]  = 7;
    ia[3]  = 11;
    ia[4]  = 14;
  } else if (rank == 2) {
    ja[0]  = 4;
    ja[1]  = 9;
    ja[2]  = 12;
    ja[3]  = 5;
    ja[4]  = 8;
    ja[5]  = 10;
    ja[6]  = 13;
    ja[7]  = 6;
    ja[8]  = 9;
    ja[9]  = 11;
    ja[10] = 14;
    ja[11] = 7;
    ja[12] = 10;
    ja[13] = 15;
    ia[0]  = 0;
    ia[1]  = 3;
    ia[2]  = 7;
    ia[3]  = 11;
    ia[4]  = 14;
  } else {
    ja[0] = 8;
    ja[1] = 13;
    ja[2] = 9;
    ja[3] = 12;
    ja[4] = 14;
    ja[5] = 10;
    ja[6] = 13;
    ja[7] = 15;
    ja[8] = 11;
    ja[9] = 14;
    ia[0] = 0;
    ia[1] = 2;
    ia[2] = 5;
    ia[3] = 8;
    ia[4] = 10;
  }

  PetscCall(MatCreate(PETSC_COMM_WORLD, &A));
  PetscCall(MatSetSizes(A, 4, 4, 16, 16));
  PetscCall(MatSetType(A, MATMPIAIJ));
  PetscCall(MatMPIAIJSetPreallocationCSR(A, ia, ja, NULL));
  PetscCall(PetscFree(ia));
  PetscCall(PetscFree(ja));
  PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
  PetscCall(MatDestroy(&A));
  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

   test:
      nsize: 4

TEST*/