xref: /petsc/src/mat/tests/ex181.c (revision bef158480efac06de457f7a665168877ab3c2fd7)
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   PetscErrorCode ierr;
12   PetscScalar    v;
13   IS             isrow;
14   PetscBool      detect_bug = PETSC_FALSE;
15 
16   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
17   ierr = PetscOptionsHasName(NULL,NULL,"-detect_bug",&detect_bug);CHKERRQ(ierr);
18   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);
19   ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
20   n    = 2*size;
21 
22   ierr = MatCreate(PETSC_COMM_WORLD,&C);CHKERRQ(ierr);
23   ierr = MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);CHKERRQ(ierr);
24   ierr = MatSetFromOptions(C);CHKERRQ(ierr);
25   ierr = MatSetUp(C);CHKERRQ(ierr);
26 
27   /*
28         This is JUST to generate a nice test matrix, all processors fill up
29     the entire matrix. This is not something one would ever do in practice.
30   */
31   ierr = MatGetOwnershipRange(C,&rstart,&rend);CHKERRQ(ierr);
32   for (i=rstart; i<rend; i++) {
33     for (j=0; j<m*n; j++) {
34       v    = i + j + 1;
35       ierr = MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES);CHKERRQ(ierr);
36     }
37   }
38   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
39   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
40   ierr = PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON);CHKERRQ(ierr);
41   ierr = MatView(C,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
42   ierr = PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
43 
44   /*
45      Generate a new matrix consisting every row and column of the original matrix
46   */
47   ierr = MatGetOwnershipRange(C,&rstart,&rend);CHKERRQ(ierr);
48 
49   /* Create parallel IS with the rows we want on THIS processor */
50   if (detect_bug && !rank) {
51     ierr = ISCreateStride(PETSC_COMM_WORLD,1,rstart,1,&isrow);CHKERRQ(ierr);
52   } else {
53     ierr = ISCreateStride(PETSC_COMM_WORLD,rend-rstart,rstart,1,&isrow);CHKERRQ(ierr);
54   }
55   ierr = MatCreateSubMatrix(C,isrow,NULL,MAT_INITIAL_MATRIX,&A);CHKERRQ(ierr);
56 
57   /* Change C to test the case MAT_REUSE_MATRIX */
58   if (!rank) {
59     i = 0; j = 0; v = 100;
60     ierr = MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES);CHKERRQ(ierr);
61   }
62   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
63   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
64 
65   ierr = MatCreateSubMatrix(C,isrow,NULL,MAT_REUSE_MATRIX,&A);CHKERRQ(ierr);
66   ierr = PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON);CHKERRQ(ierr);
67   ierr = MatView(A,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
68   ierr = PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
69 
70   /* Test MatDuplicate */
71   ierr = MatDuplicate(A,MAT_COPY_VALUES,&Adup);CHKERRQ(ierr);
72   ierr = MatDestroy(&Adup);CHKERRQ(ierr);
73 
74   ierr = ISDestroy(&isrow);CHKERRQ(ierr);
75   ierr = MatDestroy(&A);CHKERRQ(ierr);
76   ierr = MatDestroy(&C);CHKERRQ(ierr);
77   ierr = PetscFinalize();
78   return ierr;
79 }
80 
81 
82 /*TEST
83 
84    test:
85       nsize: 2
86       filter: grep -v "Mat Object"
87       requires: !complex
88 
89    test:
90       suffix: 2
91       nsize: 3
92       args: -detect_bug
93       filter: grep -v "Mat Object"
94       requires: !complex
95 
96 TEST*/
97