Actual source code: ex4.c


  2: static char help[] = "Creates a matrix, inserts some values, and tests MatCreateSubMatrices() and MatZeroEntries().\n\n";

  4: #include <petscmat.h>

  6: int main(int argc, char **argv)
  7: {
  8:   Mat         mat, submat, submat1, *submatrices;
  9:   PetscInt    m = 10, n = 10, i = 4, tmp, rstart, rend;
 10:   IS          irow, icol;
 11:   PetscScalar value = 1.0;
 12:   PetscViewer sviewer;
 13:   PetscBool   allA = PETSC_FALSE;

 16:   PetscInitialize(&argc, &argv, (char *)0, help);
 17:   PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_COMMON);
 18:   PetscViewerPushFormat(PETSC_VIEWER_STDOUT_SELF, PETSC_VIEWER_ASCII_COMMON);

 20:   MatCreate(PETSC_COMM_WORLD, &mat);
 21:   MatSetSizes(mat, PETSC_DECIDE, PETSC_DECIDE, m, n);
 22:   MatSetFromOptions(mat);
 23:   MatSetUp(mat);
 24:   MatGetOwnershipRange(mat, &rstart, &rend);
 25:   for (i = rstart; i < rend; i++) {
 26:     value = (PetscReal)i + 1;
 27:     tmp   = i % 5;
 28:     MatSetValues(mat, 1, &tmp, 1, &i, &value, INSERT_VALUES);
 29:   }
 30:   MatAssemblyBegin(mat, MAT_FINAL_ASSEMBLY);
 31:   MatAssemblyEnd(mat, MAT_FINAL_ASSEMBLY);
 32:   PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "Original matrix\n");
 33:   MatView(mat, PETSC_VIEWER_STDOUT_WORLD);

 35:   /* Test MatCreateSubMatrix_XXX_All(), i.e., submatrix = A */
 36:   PetscOptionsGetBool(NULL, NULL, "-test_all", &allA, NULL);
 37:   if (allA) {
 38:     ISCreateStride(PETSC_COMM_SELF, m, 0, 1, &irow);
 39:     ISCreateStride(PETSC_COMM_SELF, n, 0, 1, &icol);
 40:     MatCreateSubMatrices(mat, 1, &irow, &icol, MAT_INITIAL_MATRIX, &submatrices);
 41:     MatCreateSubMatrices(mat, 1, &irow, &icol, MAT_REUSE_MATRIX, &submatrices);
 42:     submat = *submatrices;

 44:     /* sviewer will cause the submatrices (one per processor) to be printed in the correct order */
 45:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "\nSubmatrices with all\n");
 46:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "--------------------\n");
 47:     PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer);
 48:     MatView(submat, sviewer);
 49:     PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer);
 50:     PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);

 52:     ISDestroy(&irow);
 53:     ISDestroy(&icol);

 55:     /* test getting a reference on a submat */
 56:     PetscObjectReference((PetscObject)submat);
 57:     MatDestroySubMatrices(1, &submatrices);
 58:     MatDestroy(&submat);
 59:   }

 61:   /* Form submatrix with rows 2-4 and columns 4-8 */
 62:   ISCreateStride(PETSC_COMM_SELF, 3, 2, 1, &irow);
 63:   ISCreateStride(PETSC_COMM_SELF, 5, 4, 1, &icol);
 64:   MatCreateSubMatrices(mat, 1, &irow, &icol, MAT_INITIAL_MATRIX, &submatrices);
 65:   submat = *submatrices;

 67:   /* Test reuse submatrices */
 68:   MatCreateSubMatrices(mat, 1, &irow, &icol, MAT_REUSE_MATRIX, &submatrices);

 70:   /* sviewer will cause the submatrices (one per processor) to be printed in the correct order */
 71:   PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "\nSubmatrices\n");
 72:   PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer);
 73:   MatView(submat, sviewer);
 74:   PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer);
 75:   PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);
 76:   PetscObjectReference((PetscObject)submat);
 77:   MatDestroySubMatrices(1, &submatrices);
 78:   MatDestroy(&submat);

 80:   /* Form submatrix with rows 2-4 and all columns */
 81:   ISDestroy(&icol);
 82:   ISCreateStride(PETSC_COMM_SELF, 10, 0, 1, &icol);
 83:   MatCreateSubMatrices(mat, 1, &irow, &icol, MAT_INITIAL_MATRIX, &submatrices);
 84:   MatCreateSubMatrices(mat, 1, &irow, &icol, MAT_REUSE_MATRIX, &submatrices);
 85:   submat = *submatrices;

 87:   PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "\nSubmatrices with allcolumns\n");
 88:   PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer);
 89:   MatView(submat, sviewer);
 90:   PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer);
 91:   PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);

 93:   /* Test MatDuplicate */
 94:   MatDuplicate(submat, MAT_COPY_VALUES, &submat1);
 95:   MatDestroy(&submat1);

 97:   /* Zero the original matrix */
 98:   PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "Original zeroed matrix\n");
 99:   MatZeroEntries(mat);
100:   MatView(mat, PETSC_VIEWER_STDOUT_WORLD);

102:   ISDestroy(&irow);
103:   ISDestroy(&icol);
104:   PetscObjectReference((PetscObject)submat);
105:   MatDestroySubMatrices(1, &submatrices);
106:   MatDestroy(&submat);
107:   MatDestroy(&mat);
108:   PetscFinalize();
109:   return 0;
110: }

112: /*TEST

114:    test:
115:       args: -mat_type aij

117:    test:
118:       suffix: 2
119:       args: -mat_type dense

121:    test:
122:       suffix: 3
123:       nsize: 3
124:       args: -mat_type aij

126:    test:
127:       suffix: 4
128:       nsize: 3
129:       args: -mat_type dense

131:    test:
132:       suffix: 5
133:       nsize: 3
134:       args: -mat_type aij -test_all

136: TEST*/