xref: /petsc/src/mat/tests/ex59.c (revision 327415f76d85372a4417cf1aaa14db707d4d6c04)
1c4762a1bSJed Brown 
2c4762a1bSJed Brown static char help[] = "Tests MatCreateSubmatrix() in parallel.";
3c4762a1bSJed Brown 
4c4762a1bSJed Brown #include <petscmat.h>
5c4762a1bSJed Brown 
6c4762a1bSJed Brown int main(int argc,char **args)
7c4762a1bSJed Brown {
8c4762a1bSJed Brown   Mat            C,A;
9c4762a1bSJed Brown   PetscInt       i,j,m = 3,n = 2,rstart,rend;
10c4762a1bSJed Brown   PetscMPIInt    size,rank;
11c4762a1bSJed Brown   PetscScalar    v;
12c4762a1bSJed Brown   IS             isrow,iscol;
13c4762a1bSJed Brown 
14*327415f7SBarry Smith   PetscFunctionBeginUser;
159566063dSJacob Faibussowitsch   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
169566063dSJacob Faibussowitsch   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
179566063dSJacob Faibussowitsch   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
18c4762a1bSJed Brown   n    = 2*size;
19c4762a1bSJed Brown 
209566063dSJacob Faibussowitsch   PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
219566063dSJacob Faibussowitsch   PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n));
229566063dSJacob Faibussowitsch   PetscCall(MatSetFromOptions(C));
239566063dSJacob Faibussowitsch   PetscCall(MatSetUp(C));
24c4762a1bSJed Brown 
25c4762a1bSJed Brown   /*
26c4762a1bSJed Brown         This is JUST to generate a nice test matrix, all processors fill up
27c4762a1bSJed Brown     the entire matrix. This is not something one would ever do in practice.
28c4762a1bSJed Brown   */
299566063dSJacob Faibussowitsch   PetscCall(MatGetOwnershipRange(C,&rstart,&rend));
30c4762a1bSJed Brown   for (i=rstart; i<rend; i++) {
31c4762a1bSJed Brown     for (j=0; j<m*n; j++) {
32c4762a1bSJed Brown       v    = i + j + 1;
339566063dSJacob Faibussowitsch       PetscCall(MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES));
34c4762a1bSJed Brown     }
35c4762a1bSJed Brown   }
36c4762a1bSJed Brown 
379566063dSJacob Faibussowitsch   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
389566063dSJacob Faibussowitsch   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
399566063dSJacob Faibussowitsch   PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON));
409566063dSJacob Faibussowitsch   PetscCall(MatView(C,PETSC_VIEWER_STDOUT_WORLD));
41c4762a1bSJed Brown 
42c4762a1bSJed Brown   /*
43c4762a1bSJed Brown      Generate a new matrix consisting of every second row and column of
44c4762a1bSJed Brown    the original matrix
45c4762a1bSJed Brown   */
469566063dSJacob Faibussowitsch   PetscCall(MatGetOwnershipRange(C,&rstart,&rend));
47c4762a1bSJed Brown   /* Create parallel IS with the rows we want on THIS processor */
489566063dSJacob Faibussowitsch   PetscCall(ISCreateStride(PETSC_COMM_WORLD,(rend-rstart)/2,rstart,2,&isrow));
49c4762a1bSJed Brown   /* Create parallel IS with the rows we want on THIS processor (same as rows for now) */
509566063dSJacob Faibussowitsch   PetscCall(ISCreateStride(PETSC_COMM_WORLD,(rend-rstart)/2,rstart,2,&iscol));
51c4762a1bSJed Brown 
529566063dSJacob Faibussowitsch   PetscCall(MatCreateSubMatrix(C,isrow,iscol,MAT_INITIAL_MATRIX,&A));
539566063dSJacob Faibussowitsch   PetscCall(MatCreateSubMatrix(C,isrow,iscol,MAT_REUSE_MATRIX,&A));
549566063dSJacob Faibussowitsch   PetscCall(MatView(A,PETSC_VIEWER_STDOUT_WORLD));
55c4762a1bSJed Brown 
569566063dSJacob Faibussowitsch   PetscCall(ISDestroy(&isrow));
579566063dSJacob Faibussowitsch   PetscCall(ISDestroy(&iscol));
589566063dSJacob Faibussowitsch   PetscCall(MatDestroy(&A));
599566063dSJacob Faibussowitsch   PetscCall(MatDestroy(&C));
609566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
61b122ec5aSJacob Faibussowitsch   return 0;
62c4762a1bSJed Brown }
63c4762a1bSJed Brown 
64c4762a1bSJed Brown /*TEST
65c4762a1bSJed Brown 
66c4762a1bSJed Brown    test:
67c4762a1bSJed Brown 
68c4762a1bSJed Brown    test:
69c4762a1bSJed Brown       suffix: 2
70c4762a1bSJed Brown       nsize: 3
71c4762a1bSJed Brown 
72c4762a1bSJed Brown    test:
73c4762a1bSJed Brown       suffix: 2_baij
74c4762a1bSJed Brown       nsize: 3
75c4762a1bSJed Brown       args: -mat_type baij
76c4762a1bSJed Brown 
77c4762a1bSJed Brown    test:
78c4762a1bSJed Brown       suffix: 2_sbaij
79c4762a1bSJed Brown       nsize: 3
80c4762a1bSJed Brown       args: -mat_type sbaij
81c4762a1bSJed Brown 
82c4762a1bSJed Brown    test:
83c4762a1bSJed Brown       suffix: baij
84c4762a1bSJed Brown       args: -mat_type baij
85c4762a1bSJed Brown       output_file: output/ex59_1_baij.out
86c4762a1bSJed Brown 
87c4762a1bSJed Brown    test:
88c4762a1bSJed Brown       suffix: sbaij
89c4762a1bSJed Brown       args: -mat_type sbaij
90c4762a1bSJed Brown       output_file: output/ex59_1_sbaij.out
91c4762a1bSJed Brown 
92c4762a1bSJed Brown TEST*/
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