1 2 static char help[] = "Partition a tiny grid using hierarchical partitioning.\n\n"; 3 4 /* 5 Include "petscmat.h" so that we can use matrices. Note that this file 6 automatically includes: 7 petscsys.h - base PETSc routines petscvec.h - vectors 8 petscmat.h - matrices 9 petscis.h - index sets 10 petscviewer.h - viewers 11 */ 12 #include <petscmat.h> 13 14 int main(int argc,char **args) 15 { 16 Mat A; 17 PetscMPIInt rank,size; 18 PetscInt *ia,*ja; 19 MatPartitioning part; 20 IS is,isn,isrows; 21 IS coarseparts,fineparts; 22 MPI_Comm comm; 23 24 PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 25 comm = PETSC_COMM_WORLD; 26 PetscCallMPI(MPI_Comm_size(comm,&size)); 27 PetscCheck(size == 4,comm,PETSC_ERR_WRONG_MPI_SIZE,"Must run with 4 processors"); 28 PetscCallMPI(MPI_Comm_rank(comm,&rank)); 29 30 PetscCall(PetscMalloc1(5,&ia)); 31 PetscCall(PetscMalloc1(16,&ja)); 32 if (rank == 0) { 33 ja[0] = 1; ja[1] = 4; ja[2] = 0; ja[3] = 2; ja[4] = 5; ja[5] = 1; ja[6] = 3; ja[7] = 6; 34 ja[8] = 2; ja[9] = 7; 35 ia[0] = 0; ia[1] = 2; ia[2] = 5; ia[3] = 8; ia[4] = 10; 36 } else if (rank == 1) { 37 ja[0] = 0; ja[1] = 5; ja[2] = 8; ja[3] = 1; ja[4] = 4; ja[5] = 6; ja[6] = 9; ja[7] = 2; 38 ja[8] = 5; ja[9] = 7; ja[10] = 10; ja[11] = 3; ja[12] = 6; ja[13] = 11; 39 ia[0] = 0; ia[1] = 3; ia[2] = 7; ia[3] = 11; ia[4] = 14; 40 } else if (rank == 2) { 41 ja[0] = 4; ja[1] = 9; ja[2] = 12; ja[3] = 5; ja[4] = 8; ja[5] = 10; ja[6] = 13; ja[7] = 6; 42 ja[8] = 9; ja[9] = 11; ja[10] = 14; ja[11] = 7; ja[12] = 10; ja[13] = 15; 43 ia[0] = 0; ia[1] = 3; ia[2] = 7; ia[3] = 11; ia[4] = 14; 44 } else { 45 ja[0] = 8; ja[1] = 13; ja[2] = 9; ja[3] = 12; ja[4] = 14; ja[5] = 10; ja[6] = 13; ja[7] = 15; 46 ja[8] = 11; ja[9] = 14; 47 ia[0] = 0; ia[1] = 2; ia[2] = 5; ia[3] = 8; ia[4] = 10; 48 } 49 PetscCall(MatCreateMPIAdj(comm,4,16,ia,ja,NULL,&A)); 50 PetscCall(MatView(A,PETSC_VIEWER_STDOUT_WORLD)); 51 /* 52 Partition the graph of the matrix 53 */ 54 PetscCall(MatPartitioningCreate(comm,&part)); 55 PetscCall(MatPartitioningSetAdjacency(part,A)); 56 PetscCall(MatPartitioningSetType(part,MATPARTITIONINGHIERARCH)); 57 PetscCall(MatPartitioningHierarchicalSetNcoarseparts(part,2)); 58 PetscCall(MatPartitioningHierarchicalSetNfineparts(part,2)); 59 PetscCall(MatPartitioningSetFromOptions(part)); 60 /* get new processor owner number of each vertex */ 61 PetscCall(MatPartitioningApply(part,&is)); 62 /* coarse parts */ 63 PetscCall(MatPartitioningHierarchicalGetCoarseparts(part,&coarseparts)); 64 PetscCall(ISView(coarseparts,PETSC_VIEWER_STDOUT_WORLD)); 65 /* fine parts */ 66 PetscCall(MatPartitioningHierarchicalGetFineparts(part,&fineparts)); 67 PetscCall(ISView(fineparts,PETSC_VIEWER_STDOUT_WORLD)); 68 /* partitioning */ 69 PetscCall(ISView(is,PETSC_VIEWER_STDOUT_WORLD)); 70 /* get new global number of each old global number */ 71 PetscCall(ISPartitioningToNumbering(is,&isn)); 72 PetscCall(ISView(isn,PETSC_VIEWER_STDOUT_WORLD)); 73 PetscCall(ISBuildTwoSided(is,NULL,&isrows)); 74 PetscCall(ISView(isrows,PETSC_VIEWER_STDOUT_WORLD)); 75 PetscCall(ISDestroy(&is)); 76 PetscCall(ISDestroy(&coarseparts)); 77 PetscCall(ISDestroy(&fineparts)); 78 PetscCall(ISDestroy(&isrows)); 79 PetscCall(ISDestroy(&isn)); 80 PetscCall(MatPartitioningDestroy(&part)); 81 /* 82 Free work space. All PETSc objects should be destroyed when they 83 are no longer needed. 84 */ 85 PetscCall(MatDestroy(&A)); 86 PetscCall(PetscFinalize()); 87 return 0; 88 } 89 90 /*TEST 91 92 test: 93 nsize: 4 94 requires: parmetis 95 TODO: tests cannot use parmetis because it produces different results on different machines 96 97 TEST*/ 98