xref: /petsc/src/mat/tests/ex300.c (revision ebead697dbf761eb322f829370bbe90b3bd93fa3)
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   PetscFunctionBeginUser;
23   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
24   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
25   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
26 
27   PetscCheck(2 == size,PETSC_COMM_WORLD,PETSC_ERR_ARG_INCOMP,"Relevant with 2 processes only");
28   PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
29 
30 #ifdef SET_2nd_PROC_TO_HAVE_NO_LOCAL_LINES
31   if (0 == rank) {
32     locallines = m;
33     d_nnz[0] = 1;
34     d_nnz[1] = 1;
35     d_nnz[2] = 1;
36   } else {
37    locallines = 0;
38   }
39 #else
40   if (0 == rank) {
41     locallines = m-1;
42     d_nnz[0] = 1;
43     d_nnz[1] = 1;
44   } else {
45     locallines = 1;
46     d_nnz[0] = 1;
47   }
48 #endif
49 
50   PetscCall(MatSetSizes(C,locallines,locallines,m,m));
51   PetscCall(MatSetFromOptions(C));
52   PetscCall(MatXAIJSetPreallocation(C,1,d_nnz,o_nnz,NULL,NULL));
53 
54   v = 2;
55   /* Assembly on the diagonal: */
56   for (i=0; i<m; i++) {
57      PetscCall(MatSetValues(C,1,&i,1,&i,&v,ADD_VALUES));
58   }
59   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
60   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
61   PetscCall(MatSetOption(C,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE));
62   PetscCall(MatSetOption(C, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE));
63   PetscCall(MatView(C,PETSC_VIEWER_STDOUT_WORLD));
64   PetscCall(MatConvert(C,MATSAME, MAT_INITIAL_MATRIX, &lMatA));
65   PetscCall(MatView(lMatA,PETSC_VIEWER_STDOUT_WORLD));
66 
67   PetscCall(MatShift(lMatA,-1.0));
68 
69   PetscCall(MatDestroy(&lMatA));
70   PetscCall(MatDestroy(&C));
71   PetscCall(PetscFinalize());
72   return 0;
73 }
74 
75 /*TEST
76 
77    test:
78       nsize: 2
79 
80 TEST*/
81