Actual source code: ex10.c


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

  4: #include <petscmat.h>

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

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

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

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

 82:   PetscCall(MatDestroy(&C));
 83:   PetscCall(PetscFinalize());
 84:   return 0;
 85: }

 87: /*TEST

 89:    test:

 91: TEST*/