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;

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

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

 35:   /* Test MatCreateSubMatrix_XXX_All(), i.e., submatrix = A */
 36:   PetscCall(PetscOptionsGetBool(NULL, NULL, "-test_all", &allA, NULL));
 37:   if (allA) {
 38:     PetscCall(ISCreateStride(PETSC_COMM_SELF, m, 0, 1, &irow));
 39:     PetscCall(ISCreateStride(PETSC_COMM_SELF, n, 0, 1, &icol));
 40:     PetscCall(MatCreateSubMatrices(mat, 1, &irow, &icol, MAT_INITIAL_MATRIX, &submatrices));
 41:     PetscCall(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:     PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "\nSubmatrices with all\n"));
 46:     PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "--------------------\n"));
 47:     PetscCall(PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer));
 48:     PetscCall(MatView(submat, sviewer));
 49:     PetscCall(PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer));
 50:     PetscCall(PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD));

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

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

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

 67:   /* Test reuse submatrices */
 68:   PetscCall(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:   PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD, "\nSubmatrices\n"));
 72:   PetscCall(PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer));
 73:   PetscCall(MatView(submat, sviewer));
 74:   PetscCall(PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer));
 75:   PetscCall(PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD));
 76:   PetscCall(PetscObjectReference((PetscObject)submat));
 77:   PetscCall(MatDestroySubMatrices(1, &submatrices));
 78:   PetscCall(MatDestroy(&submat));

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

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

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

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

102:   PetscCall(ISDestroy(&irow));
103:   PetscCall(ISDestroy(&icol));
104:   PetscCall(PetscObjectReference((PetscObject)submat));
105:   PetscCall(MatDestroySubMatrices(1, &submatrices));
106:   PetscCall(MatDestroy(&submat));
107:   PetscCall(MatDestroy(&mat));
108:   PetscCall(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*/