xref: /petsc/src/mat/tests/ex212.c (revision 58d68138c660dfb4e9f5b03334792cd4f2ffd7cc)
1 static char help[] = "Test MatCreateSubMatrix with -mat_type nest and block sizes.\n";
2 
3 #include <petscmat.h>
4 
5 int main(int argc, char **argv) {
6   Mat                    A, B, C, mats[6];
7   IS                     rows[2];
8   ISLocalToGlobalMapping cmap, rmap;
9   const PetscInt         indices[3] = {0, 1, 2};
10   PetscInt               i;
11   PetscMPIInt            size;
12 
13   PetscFunctionBeginUser;
14   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
15   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
16   PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Only coded for one process");
17   PetscCall(MatCreate(PETSC_COMM_WORLD, &A));
18   PetscCall(MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, 2, 1));
19   PetscCall(MatSetBlockSizes(A, 2, 1));
20   PetscCall(MatSetType(A, MATAIJ));
21   PetscCall(ISLocalToGlobalMappingCreate(PETSC_COMM_WORLD, 2, 1, indices, PETSC_COPY_VALUES, &rmap));
22   PetscCall(ISLocalToGlobalMappingCreate(PETSC_COMM_WORLD, 1, 1, indices, PETSC_COPY_VALUES, &cmap));
23   PetscCall(MatSetLocalToGlobalMapping(A, rmap, cmap));
24   PetscCall(ISLocalToGlobalMappingDestroy(&rmap));
25   PetscCall(ISLocalToGlobalMappingDestroy(&cmap));
26   PetscCall(ISLocalToGlobalMappingCreate(PETSC_COMM_WORLD, 1, 2, indices, PETSC_COPY_VALUES, &rmap));
27   PetscCall(ISLocalToGlobalMappingCreate(PETSC_COMM_WORLD, 1, 3, indices, PETSC_COPY_VALUES, &cmap));
28   PetscCall(MatCreate(PETSC_COMM_WORLD, &B));
29   PetscCall(MatSetSizes(B, PETSC_DECIDE, PETSC_DECIDE, 2, 3));
30   PetscCall(MatSetBlockSizes(B, 1, 1));
31   PetscCall(MatSetType(B, MATAIJ));
32   PetscCall(MatSetLocalToGlobalMapping(B, rmap, cmap));
33   PetscCall(ISLocalToGlobalMappingDestroy(&rmap));
34   PetscCall(ISLocalToGlobalMappingDestroy(&cmap));
35   PetscCall(MatSetUp(A));
36   PetscCall(MatSetUp(B));
37   mats[0] = A;
38   mats[1] = B;
39   mats[2] = A;
40   mats[3] = NULL;
41   mats[4] = B;
42   mats[5] = A;
43   PetscCall(MatCreateNest(PETSC_COMM_WORLD, 2, NULL, 3, NULL, mats, &C));
44   PetscCall(MatSetUp(C));
45   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
46   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
47   PetscCall(MatView(C, NULL));
48   PetscCall(MatNestGetISs(C, rows, NULL));
49   for (i = 0; i < 2; i++) {
50     Mat      submat;
51     IS       cols[3];
52     PetscInt j;
53     PetscCall(ISView(rows[i], NULL));
54     PetscCall(MatCreateSubMatrix(C, rows[i], NULL, MAT_INITIAL_MATRIX, &submat));
55     PetscCall(MatView(submat, NULL));
56     PetscCall(MatNestGetISs(submat, NULL, cols));
57     for (j = 0; j < 3; j++) { PetscCall(ISView(cols[j], NULL)); }
58     PetscCall(MatDestroy(&submat));
59   }
60   PetscCall(MatDestroy(&C));
61   PetscCall(MatDestroy(&B));
62   PetscCall(MatDestroy(&A));
63   PetscCall(PetscFinalize());
64   return 0;
65 }
66 
67 /*TEST
68 
69     test:
70 
71 TEST*/
72