Actual source code: ex181.c

  1: static char help[] = "Tests MatCreateSubmatrix() with entire matrix, modified from ex59.c.";

  3: #include <petscmat.h>

  5: int main(int argc, char **args)
  6: {
  7:   Mat         C, A, Adup;
  8:   PetscInt    i, j, m = 3, n = 2, rstart, rend;
  9:   PetscMPIInt size, rank;
 10:   PetscScalar v;
 11:   IS          isrow;
 12:   PetscBool   detect_bug = PETSC_FALSE;

 14:   PetscFunctionBeginUser;
 15:   PetscCall(PetscInitialize(&argc, &args, NULL, help));
 16:   PetscCall(PetscOptionsHasName(NULL, NULL, "-detect_bug", &detect_bug));
 17:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
 18:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 19:   n = 2 * size;

 21:   PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
 22:   PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
 23:   PetscCall(MatSetFromOptions(C));
 24:   PetscCall(MatSetUp(C));

 26:   /*
 27:         This is JUST to generate a nice test matrix, all processors fill up
 28:     the entire matrix. This is not something one would ever do in practice.
 29:   */
 30:   PetscCall(MatGetOwnershipRange(C, &rstart, &rend));
 31:   for (i = rstart; i < rend; i++) {
 32:     for (j = 0; j < m * n; j++) {
 33:       v = i + j + 1;
 34:       PetscCall(MatSetValues(C, 1, &i, 1, &j, &v, INSERT_VALUES));
 35:     }
 36:   }
 37:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
 38:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
 39:   PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_COMMON));
 40:   PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
 41:   PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));

 43:   /*
 44:      Generate a new matrix consisting every row and column of the original matrix
 45:   */
 46:   PetscCall(MatGetOwnershipRange(C, &rstart, &rend));

 48:   /* Create parallel IS with the rows we want on THIS processor */
 49:   if (detect_bug && rank == 0) {
 50:     PetscCall(ISCreateStride(PETSC_COMM_WORLD, 1, rstart, 1, &isrow));
 51:   } else {
 52:     PetscCall(ISCreateStride(PETSC_COMM_WORLD, rend - rstart, rstart, 1, &isrow));
 53:   }
 54:   PetscCall(MatCreateSubMatrix(C, isrow, NULL, MAT_INITIAL_MATRIX, &A));

 56:   /* Change C to test the case MAT_REUSE_MATRIX */
 57:   if (rank == 0) {
 58:     i = 0;
 59:     j = 0;
 60:     v = 100;
 61:     PetscCall(MatSetValues(C, 1, &i, 1, &j, &v, INSERT_VALUES));
 62:   }
 63:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
 64:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));

 66:   PetscCall(MatCreateSubMatrix(C, isrow, NULL, MAT_REUSE_MATRIX, &A));
 67:   PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_COMMON));
 68:   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
 69:   PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));

 71:   /* Test MatDuplicate */
 72:   PetscCall(MatDuplicate(A, MAT_COPY_VALUES, &Adup));
 73:   PetscCall(MatDestroy(&Adup));

 75:   PetscCall(ISDestroy(&isrow));
 76:   PetscCall(MatDestroy(&A));
 77:   PetscCall(MatDestroy(&C));
 78:   PetscCall(PetscFinalize());
 79:   return 0;
 80: }

 82: /*TEST

 84:    test:
 85:       nsize: 2
 86:       filter: grep -v "Mat Object"
 87:       requires: !complex

 89:    test:
 90:       suffix: 2
 91:       nsize: 3
 92:       args: -detect_bug
 93:       filter: grep -v "Mat Object"
 94:       requires: !complex

 96: TEST*/