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;
  9:   PetscInt    i, j, m = 5, n = 2, Ii, J;
 10:   PetscMPIInt rank, size;
 11:   PetscScalar v;

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

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

 77:   MatView(C, PETSC_VIEWER_STDOUT_WORLD);

 79:   MatDestroy(&C);
 80:   PetscFinalize();
 81:   return 0;
 82: }

 84: /*TEST

 86:    test:

 88: TEST*/