xref: /petsc/src/mat/tests/ex300.c (revision 7d5fd1e4d9337468ad3f05b65b7facdcd2dfd2a4)
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   PetscErrorCode    ierr;
17   PetscScalar       v;
18   Mat               lMatA;
19   PetscInt          locallines;
20   PetscInt          d_nnz[3] = {0,0,0};
21   PetscInt          o_nnz[3] = {0,0,0};
22 
23   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
24   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
25   ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRMPI(ierr);
26 
27   if (2 != size) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_ARG_INCOMP,"Relevant with 2 processes only");
28   ierr = MatCreate(PETSC_COMM_WORLD,&C);CHKERRQ(ierr);
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   ierr = MatSetSizes(C,locallines,locallines,m,m);CHKERRQ(ierr);
51   ierr = MatSetFromOptions(C);CHKERRQ(ierr);
52   ierr = MatXAIJSetPreallocation(C,1,d_nnz,o_nnz,NULL,NULL);CHKERRQ(ierr);
53 
54   v = 2;
55   /* Assembly on the diagonal: */
56   for (i=0; i<m; i++) {
57      ierr = MatSetValues(C,1,&i,1,&i,&v,ADD_VALUES);CHKERRQ(ierr);
58   }
59   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
60   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
61   ierr = MatSetOption(C,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
62   ierr = MatSetOption(C, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE);CHKERRQ(ierr);
63   ierr = MatView(C,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
64   ierr = MatConvert(C,MATSAME, MAT_INITIAL_MATRIX, &lMatA);CHKERRQ(ierr);
65   ierr = MatView(lMatA,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
66 
67   ierr = MatShift(lMatA,-1.0);CHKERRQ(ierr);
68 
69   ierr = MatDestroy(&lMatA);CHKERRQ(ierr);
70   ierr = MatDestroy(&C);CHKERRQ(ierr);
71   ierr = PetscFinalize();
72   return ierr;
73 }
74 
75 /*TEST
76 
77    test:
78       nsize: 2
79 
80 TEST*/
81