xref: /petsc/src/mat/tests/ex300.c (revision efa12513287cff49a2b9648ae83199dcbfaad71a)
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 
9 /* DEFINE this to turn on/off the bug: */
10 #define SET_2nd_PROC_TO_HAVE_NO_LOCAL_LINES
11 
12 int main(int argc,char **args)
13 {
14   Mat               C;
15   PetscInt          i,m = 3;
16   PetscMPIInt       rank,size;
17   PetscErrorCode    ierr;
18   PetscScalar       v;
19   Mat               lMatA;
20   PetscInt          locallines;
21   PetscInt          d_nnz[3] = {0,0,0};
22   PetscInt          o_nnz[3] = {0,0,0};
23 
24   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
25   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
26   ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRMPI(ierr);
27 
28   if (2 != size) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_ARG_INCOMP,"Relevant with 2 processes only");
29   ierr = MatCreate(PETSC_COMM_WORLD,&C);CHKERRQ(ierr);
30 
31 #ifdef SET_2nd_PROC_TO_HAVE_NO_LOCAL_LINES
32   if (0 == rank) {
33     locallines = m;
34     d_nnz[0] = 1;
35     d_nnz[1] = 1;
36     d_nnz[2] = 1;
37   } else {
38    locallines = 0;
39   }
40 #else
41   if (0 == rank) {
42     locallines = m-1;
43     d_nnz[0] = 1;
44     d_nnz[1] = 1;
45   } else {
46     locallines = 1;
47     d_nnz[0] = 1;
48   }
49 #endif
50 
51   ierr = MatSetSizes(C,locallines,locallines,m,m);CHKERRQ(ierr);
52   ierr = MatSetFromOptions(C);CHKERRQ(ierr);
53   ierr = MatXAIJSetPreallocation(C,1,d_nnz,o_nnz,NULL,NULL);CHKERRQ(ierr);
54 
55   v = 2;
56   /* Assembly on the diagonal: */
57   for (i=0; i<m; i++) {
58      ierr = MatSetValues(C,1,&i,1,&i,&v,ADD_VALUES);CHKERRQ(ierr);
59   }
60   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
61   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
62   ierr = MatSetOption(C,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
63   ierr = MatSetOption(C, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE);CHKERRQ(ierr);
64   ierr = MatView(C,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
65   ierr = MatConvert(C,MATSAME, MAT_INITIAL_MATRIX, &lMatA);CHKERRQ(ierr);
66   ierr = MatView(lMatA,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
67 
68   ierr = MatShift(lMatA,-1.0);CHKERRQ(ierr);
69 
70   ierr = MatDestroy(&lMatA);CHKERRQ(ierr);
71   ierr = MatDestroy(&C);CHKERRQ(ierr);
72   ierr = PetscFinalize();
73   return ierr;
74 }
75 
76 
77 /*TEST
78 
79    test:
80       nsize: 2
81 
82 TEST*/
83