xref: /petsc/src/mat/tests/ex59.c (revision b122ec5aa1bd4469eb4e0673542fb7de3f411254)
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*b122ec5aSJacob Faibussowitsch   CHKERRQ(PetscInitialize(&argc,&args,(char*)0,help));
155f80ce2aSJacob Faibussowitsch   CHKERRMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
165f80ce2aSJacob Faibussowitsch   CHKERRMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
17c4762a1bSJed Brown   n    = 2*size;
18c4762a1bSJed Brown 
195f80ce2aSJacob Faibussowitsch   CHKERRQ(MatCreate(PETSC_COMM_WORLD,&C));
205f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n));
215f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetFromOptions(C));
225f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetUp(C));
23c4762a1bSJed Brown 
24c4762a1bSJed Brown   /*
25c4762a1bSJed Brown         This is JUST to generate a nice test matrix, all processors fill up
26c4762a1bSJed Brown     the entire matrix. This is not something one would ever do in practice.
27c4762a1bSJed Brown   */
285f80ce2aSJacob Faibussowitsch   CHKERRQ(MatGetOwnershipRange(C,&rstart,&rend));
29c4762a1bSJed Brown   for (i=rstart; i<rend; i++) {
30c4762a1bSJed Brown     for (j=0; j<m*n; j++) {
31c4762a1bSJed Brown       v    = i + j + 1;
325f80ce2aSJacob Faibussowitsch       CHKERRQ(MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES));
33c4762a1bSJed Brown     }
34c4762a1bSJed Brown   }
35c4762a1bSJed Brown 
365f80ce2aSJacob Faibussowitsch   CHKERRQ(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
375f80ce2aSJacob Faibussowitsch   CHKERRQ(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
385f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON));
395f80ce2aSJacob Faibussowitsch   CHKERRQ(MatView(C,PETSC_VIEWER_STDOUT_WORLD));
40c4762a1bSJed Brown 
41c4762a1bSJed Brown   /*
42c4762a1bSJed Brown      Generate a new matrix consisting of every second row and column of
43c4762a1bSJed Brown    the original matrix
44c4762a1bSJed Brown   */
455f80ce2aSJacob Faibussowitsch   CHKERRQ(MatGetOwnershipRange(C,&rstart,&rend));
46c4762a1bSJed Brown   /* Create parallel IS with the rows we want on THIS processor */
475f80ce2aSJacob Faibussowitsch   CHKERRQ(ISCreateStride(PETSC_COMM_WORLD,(rend-rstart)/2,rstart,2,&isrow));
48c4762a1bSJed Brown   /* Create parallel IS with the rows we want on THIS processor (same as rows for now) */
495f80ce2aSJacob Faibussowitsch   CHKERRQ(ISCreateStride(PETSC_COMM_WORLD,(rend-rstart)/2,rstart,2,&iscol));
50c4762a1bSJed Brown 
515f80ce2aSJacob Faibussowitsch   CHKERRQ(MatCreateSubMatrix(C,isrow,iscol,MAT_INITIAL_MATRIX,&A));
525f80ce2aSJacob Faibussowitsch   CHKERRQ(MatCreateSubMatrix(C,isrow,iscol,MAT_REUSE_MATRIX,&A));
535f80ce2aSJacob Faibussowitsch   CHKERRQ(MatView(A,PETSC_VIEWER_STDOUT_WORLD));
54c4762a1bSJed Brown 
555f80ce2aSJacob Faibussowitsch   CHKERRQ(ISDestroy(&isrow));
565f80ce2aSJacob Faibussowitsch   CHKERRQ(ISDestroy(&iscol));
575f80ce2aSJacob Faibussowitsch   CHKERRQ(MatDestroy(&A));
585f80ce2aSJacob Faibussowitsch   CHKERRQ(MatDestroy(&C));
59*b122ec5aSJacob Faibussowitsch   CHKERRQ(PetscFinalize());
60*b122ec5aSJacob Faibussowitsch   return 0;
61c4762a1bSJed Brown }
62c4762a1bSJed Brown 
63c4762a1bSJed Brown /*TEST
64c4762a1bSJed Brown 
65c4762a1bSJed Brown    test:
66c4762a1bSJed Brown 
67c4762a1bSJed Brown    test:
68c4762a1bSJed Brown       suffix: 2
69c4762a1bSJed Brown       nsize: 3
70c4762a1bSJed Brown 
71c4762a1bSJed Brown    test:
72c4762a1bSJed Brown       suffix: 2_baij
73c4762a1bSJed Brown       nsize: 3
74c4762a1bSJed Brown       args: -mat_type baij
75c4762a1bSJed Brown 
76c4762a1bSJed Brown    test:
77c4762a1bSJed Brown       suffix: 2_sbaij
78c4762a1bSJed Brown       nsize: 3
79c4762a1bSJed Brown       args: -mat_type sbaij
80c4762a1bSJed Brown 
81c4762a1bSJed Brown    test:
82c4762a1bSJed Brown       suffix: baij
83c4762a1bSJed Brown       args: -mat_type baij
84c4762a1bSJed Brown       output_file: output/ex59_1_baij.out
85c4762a1bSJed Brown 
86c4762a1bSJed Brown    test:
87c4762a1bSJed Brown       suffix: sbaij
88c4762a1bSJed Brown       args: -mat_type sbaij
89c4762a1bSJed Brown       output_file: output/ex59_1_sbaij.out
90c4762a1bSJed Brown 
91c4762a1bSJed Brown TEST*/
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