xref: /petsc/src/mat/tests/ex181.c (revision ffa8c5705e8ab2cf85ee1d14dbe507a6e2eb5283)
1 
2 static char help[] = "Tests MatCreateSubmatrix() with entire matrix, modified from ex59.c.";
3 
4 #include <petscmat.h>
5 
6 int main(int argc,char **args)
7 {
8   Mat            C,A,Adup;
9   PetscInt       i,j,m = 3,n = 2,rstart,rend;
10   PetscMPIInt    size,rank;
11   PetscScalar    v;
12   IS             isrow;
13   PetscBool      detect_bug = PETSC_FALSE;
14 
15   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
16   PetscCall(PetscOptionsHasName(NULL,NULL,"-detect_bug",&detect_bug));
17   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
18   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
19   n    = 2*size;
20 
21   PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
22   PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n));
23   PetscCall(MatSetFromOptions(C));
24   PetscCall(MatSetUp(C));
25 
26   /*
27         This is JUST to generate a nice test matrix, all processors fill up
28     the entire matrix. This is not something one would ever do in practice.
29   */
30   PetscCall(MatGetOwnershipRange(C,&rstart,&rend));
31   for (i=rstart; i<rend; i++) {
32     for (j=0; j<m*n; j++) {
33       v    = i + j + 1;
34       PetscCall(MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES));
35     }
36   }
37   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
38   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
39   PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON));
40   PetscCall(MatView(C,PETSC_VIEWER_STDOUT_WORLD));
41   PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
42 
43   /*
44      Generate a new matrix consisting every row and column of the original matrix
45   */
46   PetscCall(MatGetOwnershipRange(C,&rstart,&rend));
47 
48   /* Create parallel IS with the rows we want on THIS processor */
49   if (detect_bug && rank == 0) {
50     PetscCall(ISCreateStride(PETSC_COMM_WORLD,1,rstart,1,&isrow));
51   } else {
52     PetscCall(ISCreateStride(PETSC_COMM_WORLD,rend-rstart,rstart,1,&isrow));
53   }
54   PetscCall(MatCreateSubMatrix(C,isrow,NULL,MAT_INITIAL_MATRIX,&A));
55 
56   /* Change C to test the case MAT_REUSE_MATRIX */
57   if (rank == 0) {
58     i = 0; j = 0; v = 100;
59     PetscCall(MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES));
60   }
61   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
62   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
63 
64   PetscCall(MatCreateSubMatrix(C,isrow,NULL,MAT_REUSE_MATRIX,&A));
65   PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON));
66   PetscCall(MatView(A,PETSC_VIEWER_STDOUT_WORLD));
67   PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
68 
69   /* Test MatDuplicate */
70   PetscCall(MatDuplicate(A,MAT_COPY_VALUES,&Adup));
71   PetscCall(MatDestroy(&Adup));
72 
73   PetscCall(ISDestroy(&isrow));
74   PetscCall(MatDestroy(&A));
75   PetscCall(MatDestroy(&C));
76   PetscCall(PetscFinalize());
77   return 0;
78 }
79 
80 /*TEST
81 
82    test:
83       nsize: 2
84       filter: grep -v "Mat Object"
85       requires: !complex
86 
87    test:
88       suffix: 2
89       nsize: 3
90       args: -detect_bug
91       filter: grep -v "Mat Object"
92       requires: !complex
93 
94 TEST*/
95