Actual source code: ex82.c
petsc-3.10.5 2019-03-28
2: static char help[] = "Partition a tiny grid using hierarchical partitioning.\n\n";
4: /*T
5: Concepts: partitioning
6: Processors: 4
7: T*/
11: /*
12: Include "petscmat.h" so that we can use matrices. Note that this file
13: automatically includes:
14: petscsys.h - base PETSc routines petscvec.h - vectors
15: petscmat.h - matrices
16: petscis.h - index sets
17: petscviewer.h - viewers
18: */
19: #include <petscmat.h>
21: int main(int argc,char **args)
22: {
23: Mat A;
24: PetscErrorCode ierr;
25: PetscMPIInt rank,size;
26: PetscInt *ia,*ja;
27: MatPartitioning part;
28: IS is,isn,isrows;
29: IS coarseparts,fineparts;
30: MPI_Comm comm;
32: PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
33: comm = PETSC_COMM_WORLD;
34: MPI_Comm_size(comm,&size);
35: if (size != 4) SETERRQ(comm,1,"Must run with 4 processors");
36: MPI_Comm_rank(comm,&rank);
38: PetscMalloc1(5,&ia);
39: PetscMalloc1(16,&ja);
40: if (!rank) {
41: ja[0] = 1; ja[1] = 4; ja[2] = 0; ja[3] = 2; ja[4] = 5; ja[5] = 1; ja[6] = 3; ja[7] = 6;
42: ja[8] = 2; ja[9] = 7;
43: ia[0] = 0; ia[1] = 2; ia[2] = 5; ia[3] = 8; ia[4] = 10;
44: } else if (rank == 1) {
45: ja[0] = 0; ja[1] = 5; ja[2] = 8; ja[3] = 1; ja[4] = 4; ja[5] = 6; ja[6] = 9; ja[7] = 2;
46: ja[8] = 5; ja[9] = 7; ja[10] = 10; ja[11] = 3; ja[12] = 6; ja[13] = 11;
47: ia[0] = 0; ia[1] = 3; ia[2] = 7; ia[3] = 11; ia[4] = 14;
48: } else if (rank == 2) {
49: ja[0] = 4; ja[1] = 9; ja[2] = 12; ja[3] = 5; ja[4] = 8; ja[5] = 10; ja[6] = 13; ja[7] = 6;
50: ja[8] = 9; ja[9] = 11; ja[10] = 14; ja[11] = 7; ja[12] = 10; ja[13] = 15;
51: ia[0] = 0; ia[1] = 3; ia[2] = 7; ia[3] = 11; ia[4] = 14;
52: } else {
53: ja[0] = 8; ja[1] = 13; ja[2] = 9; ja[3] = 12; ja[4] = 14; ja[5] = 10; ja[6] = 13; ja[7] = 15;
54: ja[8] = 11; ja[9] = 14;
55: ia[0] = 0; ia[1] = 2; ia[2] = 5; ia[3] = 8; ia[4] = 10;
56: }
57: MatCreateMPIAdj(comm,4,16,ia,ja,NULL,&A);
58: MatView(A,PETSC_VIEWER_STDOUT_WORLD);
59: /*
60: Partition the graph of the matrix
61: */
62: MatPartitioningCreate(comm,&part);
63: MatPartitioningSetAdjacency(part,A);
64: MatPartitioningSetType(part,MATPARTITIONINGHIERARCH);
65: MatPartitioningHierarchicalSetNcoarseparts(part,2);
66: MatPartitioningHierarchicalSetNfineparts(part,2);
67: MatPartitioningSetFromOptions(part);
68: /* get new processor owner number of each vertex */
69: MatPartitioningApply(part,&is);
70: /* coarse parts */
71: MatPartitioningHierarchicalGetCoarseparts(part,&coarseparts);
72: ISView(coarseparts,PETSC_VIEWER_STDOUT_WORLD);
73: /* fine parts */
74: MatPartitioningHierarchicalGetFineparts(part,&fineparts);
75: ISView(fineparts,PETSC_VIEWER_STDOUT_WORLD);
76: /* partitioning */
77: ISView(is,PETSC_VIEWER_STDOUT_WORLD);
78: /* get new global number of each old global number */
79: ISPartitioningToNumbering(is,&isn);
80: ISView(isn,PETSC_VIEWER_STDOUT_WORLD);
81: ISBuildTwoSided(is,NULL,&isrows);
82: ISView(isrows,PETSC_VIEWER_STDOUT_WORLD);
83: ISDestroy(&is);
84: ISDestroy(&coarseparts);
85: ISDestroy(&fineparts);
86: ISDestroy(&isrows);
87: ISDestroy(&isn);
88: MatPartitioningDestroy(&part);
89: /*
90: Free work space. All PETSc objects should be destroyed when they
91: are no longer needed.
92: */
93: MatDestroy(&A);
94: PetscFinalize();
95: return ierr;
96: }
99: /*TEST
101: test:
102: nsize: 4
103: requires: parmetis
104: TODO: tests cannot use parmetis because it produces different results on different machines
106: TEST*/