xref: /petsc/src/mat/tests/ex300.c (revision 503c0ea9b45bcfbcebbb1ea5341243bbc69f0bea)
1 
2 static char help[] = "Show MatShift BUG happening after copying a matrix with no rows on a process";
3 /*
4    Contributed by: Eric Chamberland
5 */
6 #include <petscmat.h>
7 
8 /* DEFINE this to turn on/off the bug: */
9 #define SET_2nd_PROC_TO_HAVE_NO_LOCAL_LINES
10 
11 int main(int argc,char **args)
12 {
13   Mat               C;
14   PetscInt          i,m = 3;
15   PetscMPIInt       rank,size;
16   PetscScalar       v;
17   Mat               lMatA;
18   PetscInt          locallines;
19   PetscInt          d_nnz[3] = {0,0,0};
20   PetscInt          o_nnz[3] = {0,0,0};
21 
22   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
23   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
24   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
25 
26   PetscCheckFalse(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++) {
56      PetscCall(MatSetValues(C,1,&i,1,&i,&v,ADD_VALUES));
57   }
58   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
59   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
60   PetscCall(MatSetOption(C,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE));
61   PetscCall(MatSetOption(C, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE));
62   PetscCall(MatView(C,PETSC_VIEWER_STDOUT_WORLD));
63   PetscCall(MatConvert(C,MATSAME, MAT_INITIAL_MATRIX, &lMatA));
64   PetscCall(MatView(lMatA,PETSC_VIEWER_STDOUT_WORLD));
65 
66   PetscCall(MatShift(lMatA,-1.0));
67 
68   PetscCall(MatDestroy(&lMatA));
69   PetscCall(MatDestroy(&C));
70   PetscCall(PetscFinalize());
71   return 0;
72 }
73 
74 /*TEST
75 
76    test:
77       nsize: 2
78 
79 TEST*/
80