xref: /petsc/src/mat/tests/ex21.c (revision 73fdd05bb67e49f40fd8fd311695ff6fdf0b9b8a)
1 
2 static char help[] = "Tests converting a parallel AIJ formatted matrix to the parallel Row format.\n\
3  This also tests MatGetRow() and MatRestoreRow() for the parallel case.\n\n";
4 
5 #include <petscmat.h>
6 
7 int main(int argc, char **args)
8 {
9   Mat                C, A;
10   PetscInt           i, j, m = 3, n = 2, Ii, J, rstart, rend, nz;
11   PetscMPIInt        rank, size;
12   const PetscInt    *idx;
13   PetscScalar        v;
14   const PetscScalar *values;
15 
16   PetscFunctionBeginUser;
17   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
18   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
19   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
20   n = 2 * size;
21 
22   /* create the matrix for the five point stencil, YET AGAIN*/
23   PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
24   PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
25   PetscCall(MatSetFromOptions(C));
26   PetscCall(MatMPIAIJSetPreallocation(C, 5, NULL, 5, NULL));
27   PetscCall(MatSeqAIJSetPreallocation(C, 5, NULL));
28   for (i = 0; i < m; i++) {
29     for (j = 2 * rank; j < 2 * rank + 2; j++) {
30       v  = -1.0;
31       Ii = j + n * i;
32       if (i > 0) {
33         J = Ii - n;
34         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
35       }
36       if (i < m - 1) {
37         J = Ii + n;
38         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
39       }
40       if (j > 0) {
41         J = Ii - 1;
42         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
43       }
44       if (j < n - 1) {
45         J = Ii + 1;
46         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
47       }
48       v = 4.0;
49       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
50     }
51   }
52   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
53   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
54   PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO));
55   PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
56   PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
57   PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
58 
59   PetscCall(MatGetOwnershipRange(C, &rstart, &rend));
60   for (i = rstart; i < rend; i++) {
61     PetscCall(MatGetRow(C, i, &nz, &idx, &values));
62     PetscCall(PetscSynchronizedFPrintf(PETSC_COMM_WORLD, stdout, "[%d] get row %" PetscInt_FMT ": ", rank, i));
63     for (j = 0; j < nz; j++) PetscCall(PetscSynchronizedFPrintf(PETSC_COMM_WORLD, stdout, "%" PetscInt_FMT " %g  ", idx[j], (double)PetscRealPart(values[j])));
64     PetscCall(PetscSynchronizedFPrintf(PETSC_COMM_WORLD, stdout, "\n"));
65     PetscCall(MatRestoreRow(C, i, &nz, &idx, &values));
66   }
67   PetscCall(PetscSynchronizedFlush(PETSC_COMM_WORLD, stdout));
68 
69   PetscCall(MatConvert(C, MATSAME, MAT_INITIAL_MATRIX, &A));
70   PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO));
71   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
72   PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
73   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
74 
75   PetscCall(MatDestroy(&A));
76   PetscCall(MatDestroy(&C));
77   PetscCall(PetscFinalize());
78   return 0;
79 }
80 
81 /*TEST
82 
83    test:
84       args: -mat_type seqaij
85 
86 TEST*/
87