Actual source code: ex10.c

  1: static char help[] = "Tests repeated use of assembly for matrices.\n\n";

  3: #include <petscmat.h>

  5: int main(int argc, char **args)
  6: {
  7:   Mat         C, B;
  8:   PetscInt    i, j, m = 5, n = 2, Ii, J;
  9:   PetscMPIInt rank, size;
 10:   PetscScalar v;

 12:   PetscFunctionBeginUser;
 13:   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
 14:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
 15:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 16:   n = 2 * size;

 18:   /* create the matrix for the five point stencil, YET AGAIN*/
 19:   PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
 20:   PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
 21:   PetscCall(MatSetFromOptions(C));
 22:   PetscCall(MatSetUp(C));
 23:   PetscCall(MatDuplicate(C, MAT_DO_NOT_COPY_VALUES, &B)); /* test that SeqAIJ non-preallocated matrices can be duplicated */
 24:   PetscCall(MatDestroy(&C));
 25:   C = B;
 26:   for (i = 0; i < m; i++) {
 27:     for (j = 2 * rank; j < 2 * rank + 2; j++) {
 28:       v  = -1.0;
 29:       Ii = j + n * i;
 30:       if (i > 0) {
 31:         J = Ii - n;
 32:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 33:       }
 34:       if (i < m - 1) {
 35:         J = Ii + n;
 36:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 37:       }
 38:       if (j > 0) {
 39:         J = Ii - 1;
 40:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 41:       }
 42:       if (j < n - 1) {
 43:         J = Ii + 1;
 44:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 45:       }
 46:       v = 4.0;
 47:       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
 48:     }
 49:   }
 50:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
 51:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
 52:   for (i = 0; i < m; i++) {
 53:     for (j = 2 * rank; j < 2 * rank + 2; j++) {
 54:       v  = 1.0;
 55:       Ii = j + n * i;
 56:       if (i > 0) {
 57:         J = Ii - n;
 58:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 59:       }
 60:       if (i < m - 1) {
 61:         J = Ii + n;
 62:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 63:       }
 64:       if (j > 0) {
 65:         J = Ii - 1;
 66:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 67:       }
 68:       if (j < n - 1) {
 69:         J = Ii + 1;
 70:         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
 71:       }
 72:       v = -4.0;
 73:       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
 74:     }
 75:   }
 76:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
 77:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));

 79:   PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));

 81:   PetscCall(MatDestroy(&C));
 82:   PetscCall(PetscFinalize());
 83:   return 0;
 84: }

 86: /*TEST

 88:    test:

 90: TEST*/