xref: /petsc/src/mat/tests/ex87.c (revision df4cd43f92eaa320656440c40edb1046daee8f75)
1 
2 static char help[] = "Tests MatCreateSubMatrices() for SBAIJ matrices\n\n";
3 
4 #include <petscmat.h>
5 
6 int main(int argc, char **args)
7 {
8   Mat         BAIJ, SBAIJ, *subBAIJ, *subSBAIJ;
9   PetscViewer viewer;
10   char        file[PETSC_MAX_PATH_LEN];
11   PetscBool   flg;
12   PetscInt    n = 2, issize, M, N;
13   PetscMPIInt rank;
14   IS          isrow, iscol, irow[n], icol[n];
15 
16   PetscFunctionBeginUser;
17   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
18   PetscCall(PetscOptionsGetString(NULL, NULL, "-f", file, sizeof(file), &flg));
19   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, file, FILE_MODE_READ, &viewer));
20 
21   PetscCall(MatCreate(PETSC_COMM_WORLD, &BAIJ));
22   PetscCall(MatSetType(BAIJ, MATMPIBAIJ));
23   PetscCall(MatLoad(BAIJ, viewer));
24   PetscCall(PetscViewerDestroy(&viewer));
25 
26   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, file, FILE_MODE_READ, &viewer));
27   PetscCall(MatCreate(PETSC_COMM_WORLD, &SBAIJ));
28   PetscCall(MatSetType(SBAIJ, MATMPISBAIJ));
29   PetscCall(MatLoad(SBAIJ, viewer));
30   PetscCall(PetscViewerDestroy(&viewer));
31 
32   PetscCall(MatGetSize(BAIJ, &M, &N));
33   issize = M / 4;
34   PetscCall(ISCreateStride(PETSC_COMM_SELF, issize, 0, 1, &isrow));
35   irow[0] = irow[1] = isrow;
36   issize            = N / 2;
37   PetscCall(ISCreateStride(PETSC_COMM_SELF, issize, 0, 1, &iscol));
38   icol[0] = icol[1] = iscol;
39   PetscCall(MatCreateSubMatrices(BAIJ, n, irow, icol, MAT_INITIAL_MATRIX, &subBAIJ));
40   PetscCall(MatCreateSubMatrices(BAIJ, n, irow, icol, MAT_REUSE_MATRIX, &subBAIJ));
41 
42   /* irow and icol must be same for SBAIJ matrices! */
43   icol[0] = icol[1] = isrow;
44   PetscCall(MatCreateSubMatrices(SBAIJ, n, irow, icol, MAT_INITIAL_MATRIX, &subSBAIJ));
45   PetscCall(MatCreateSubMatrices(SBAIJ, n, irow, icol, MAT_REUSE_MATRIX, &subSBAIJ));
46 
47   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
48   if (rank == 0) {
49     PetscCall(MatView(subBAIJ[0], PETSC_VIEWER_STDOUT_SELF));
50     PetscCall(MatView(subSBAIJ[0], PETSC_VIEWER_STDOUT_SELF));
51   }
52 
53   /* Free data structures */
54   PetscCall(ISDestroy(&isrow));
55   PetscCall(ISDestroy(&iscol));
56   PetscCall(MatDestroySubMatrices(n, &subBAIJ));
57   PetscCall(MatDestroySubMatrices(n, &subSBAIJ));
58   PetscCall(MatDestroy(&BAIJ));
59   PetscCall(MatDestroy(&SBAIJ));
60 
61   PetscCall(PetscFinalize());
62   return 0;
63 }
64