Actual source code: ex80.c
2: static char help[] = "Partition tiny grid.\n\n";
4: /*T
5: Concepts: partitioning
6: Processors: 4
7: T*/
9: /*
10: Include "petscmat.h" so that we can use matrices. Note that this file
11: automatically includes:
12: petscsys.h - base PETSc routines petscvec.h - vectors
13: petscmat.h - matrices
14: petscis.h - index sets
15: petscviewer.h - viewers
16: */
17: #include <petscmat.h>
19: int main(int argc,char **args)
20: {
21: Mat A;
22: PetscMPIInt rank,size;
23: PetscInt *ia,*ja;
24: MatPartitioning part;
25: IS is,isn;
27: PetscInitialize(&argc,&args,(char*)0,help);
28: MPI_Comm_size(PETSC_COMM_WORLD,&size);
30: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
32: PetscMalloc1(5,&ia);
33: PetscMalloc1(16,&ja);
34: if (rank == 0) {
35: ja[0] = 1; ja[1] = 4; ja[2] = 0; ja[3] = 2; ja[4] = 5; ja[5] = 1; ja[6] = 3; ja[7] = 6;
36: ja[8] = 2; ja[9] = 7;
37: ia[0] = 0; ia[1] = 2; ia[2] = 5; ia[3] = 8; ia[4] = 10;
38: } else if (rank == 1) {
39: ja[0] = 0; ja[1] = 5; ja[2] = 8; ja[3] = 1; ja[4] = 4; ja[5] = 6; ja[6] = 9; ja[7] = 2;
40: ja[8] = 5; ja[9] = 7; ja[10] = 10; ja[11] = 3; ja[12] = 6; ja[13] = 11;
41: ia[0] = 0; ia[1] = 3; ia[2] = 7; ia[3] = 11; ia[4] = 14;
42: } else if (rank == 2) {
43: ja[0] = 4; ja[1] = 9; ja[2] = 12; ja[3] = 5; ja[4] = 8; ja[5] = 10; ja[6] = 13; ja[7] = 6;
44: ja[8] = 9; ja[9] = 11; ja[10] = 14; ja[11] = 7; ja[12] = 10; ja[13] = 15;
45: ia[0] = 0; ia[1] = 3; ia[2] = 7; ia[3] = 11; ia[4] = 14;
46: } else {
47: ja[0] = 8; ja[1] = 13; ja[2] = 9; ja[3] = 12; ja[4] = 14; ja[5] = 10; ja[6] = 13; ja[7] = 15;
48: ja[8] = 11; ja[9] = 14;
49: ia[0] = 0; ia[1] = 2; ia[2] = 5; ia[3] = 8; ia[4] = 10;
50: }
52: MatCreateMPIAdj(PETSC_COMM_WORLD,4,16,ia,ja,NULL,&A);
53: MatView(A,PETSC_VIEWER_STDOUT_WORLD);
55: /*
56: Partition the graph of the matrix
57: */
58: MatPartitioningCreate(PETSC_COMM_WORLD,&part);
59: MatPartitioningSetAdjacency(part,A);
60: MatPartitioningSetFromOptions(part);
61: /* get new processor owner number of each vertex */
62: MatPartitioningApply(part,&is);
63: /* get new global number of each old global number */
64: ISPartitioningToNumbering(is,&isn);
65: ISView(isn,PETSC_VIEWER_STDOUT_WORLD);
66: ISDestroy(&is);
68: ISDestroy(&isn);
69: MatPartitioningDestroy(&part);
71: /*
72: Free work space. All PETSc objects should be destroyed when they
73: are no longer needed.
74: */
75: MatDestroy(&A);
77: PetscFinalize();
78: return 0;
79: }