xref: /petsc/src/mat/tests/ex300.c (revision 732aec7a18f2199fb53bb9a2f3aef439a834ce31)
1 static char help[] = "Show MatShift BUG happening after copying a matrix with no rows on a process";
2 /*
3    Contributed by: Eric Chamberland
4 */
5 #include <petscmat.h>
6 
7 /* DEFINE this to turn on/off the bug: */
8 #define SET_2nd_PROC_TO_HAVE_NO_LOCAL_LINES
9 
main(int argc,char ** args)10 int main(int argc, char **args)
11 {
12   Mat         C;
13   PetscInt    i, m = 3;
14   PetscMPIInt rank, size;
15   PetscScalar v;
16   Mat         lMatA;
17   PetscInt    locallines;
18   PetscInt    d_nnz[3] = {0, 0, 0};
19   PetscInt    o_nnz[3] = {0, 0, 0};
20 
21   PetscFunctionBeginUser;
22   PetscCall(PetscInitialize(&argc, &args, NULL, help));
23   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
24   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
25 
26   PetscCheck(2 == size, PETSC_COMM_WORLD, PETSC_ERR_ARG_INCOMP, "Relevant with 2 processes only");
27   PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
28 
29 #ifdef SET_2nd_PROC_TO_HAVE_NO_LOCAL_LINES
30   if (0 == rank) {
31     locallines = m;
32     d_nnz[0]   = 1;
33     d_nnz[1]   = 1;
34     d_nnz[2]   = 1;
35   } else {
36     locallines = 0;
37   }
38 #else
39   if (0 == rank) {
40     locallines = m - 1;
41     d_nnz[0]   = 1;
42     d_nnz[1]   = 1;
43   } else {
44     locallines = 1;
45     d_nnz[0]   = 1;
46   }
47 #endif
48 
49   PetscCall(MatSetSizes(C, locallines, locallines, m, m));
50   PetscCall(MatSetFromOptions(C));
51   PetscCall(MatXAIJSetPreallocation(C, 1, d_nnz, o_nnz, NULL, NULL));
52 
53   v = 2;
54   /* Assembly on the diagonal: */
55   for (i = 0; i < m; i++) PetscCall(MatSetValues(C, 1, &i, 1, &i, &v, ADD_VALUES));
56   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
57   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
58   PetscCall(MatSetOption(C, MAT_NEW_NONZERO_LOCATION_ERR, PETSC_TRUE));
59   PetscCall(MatSetOption(C, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE));
60   PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
61   PetscCall(MatConvert(C, MATSAME, MAT_INITIAL_MATRIX, &lMatA));
62   PetscCall(MatView(lMatA, PETSC_VIEWER_STDOUT_WORLD));
63 
64   PetscCall(MatShift(lMatA, -1.0));
65 
66   PetscCall(MatDestroy(&lMatA));
67   PetscCall(MatDestroy(&C));
68   PetscCall(PetscFinalize());
69   return 0;
70 }
71 
72 /*TEST
73 
74    test:
75       nsize: 2
76 
77 TEST*/
78