1 static char help[] = "Partition a tiny grid using hierarchical partitioning.\n\n"; 2 3 /* 4 Include "petscmat.h" so that we can use matrices. Note that this file 5 automatically includes: 6 petscsys.h - base PETSc routines petscvec.h - vectors 7 petscmat.h - matrices 8 petscis.h - index sets 9 petscviewer.h - viewers 10 */ 11 #include <petscmat.h> 12 13 int main(int argc, char **args) 14 { 15 Mat A; 16 PetscMPIInt rank, size; 17 PetscInt *ia, *ja; 18 MatPartitioning part; 19 IS is, isn, isrows; 20 IS coarseparts, fineparts; 21 MPI_Comm comm; 22 23 PetscFunctionBeginUser; 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; 34 ja[1] = 4; 35 ja[2] = 0; 36 ja[3] = 2; 37 ja[4] = 5; 38 ja[5] = 1; 39 ja[6] = 3; 40 ja[7] = 6; 41 ja[8] = 2; 42 ja[9] = 7; 43 ia[0] = 0; 44 ia[1] = 2; 45 ia[2] = 5; 46 ia[3] = 8; 47 ia[4] = 10; 48 } else if (rank == 1) { 49 ja[0] = 0; 50 ja[1] = 5; 51 ja[2] = 8; 52 ja[3] = 1; 53 ja[4] = 4; 54 ja[5] = 6; 55 ja[6] = 9; 56 ja[7] = 2; 57 ja[8] = 5; 58 ja[9] = 7; 59 ja[10] = 10; 60 ja[11] = 3; 61 ja[12] = 6; 62 ja[13] = 11; 63 ia[0] = 0; 64 ia[1] = 3; 65 ia[2] = 7; 66 ia[3] = 11; 67 ia[4] = 14; 68 } else if (rank == 2) { 69 ja[0] = 4; 70 ja[1] = 9; 71 ja[2] = 12; 72 ja[3] = 5; 73 ja[4] = 8; 74 ja[5] = 10; 75 ja[6] = 13; 76 ja[7] = 6; 77 ja[8] = 9; 78 ja[9] = 11; 79 ja[10] = 14; 80 ja[11] = 7; 81 ja[12] = 10; 82 ja[13] = 15; 83 ia[0] = 0; 84 ia[1] = 3; 85 ia[2] = 7; 86 ia[3] = 11; 87 ia[4] = 14; 88 } else { 89 ja[0] = 8; 90 ja[1] = 13; 91 ja[2] = 9; 92 ja[3] = 12; 93 ja[4] = 14; 94 ja[5] = 10; 95 ja[6] = 13; 96 ja[7] = 15; 97 ja[8] = 11; 98 ja[9] = 14; 99 ia[0] = 0; 100 ia[1] = 2; 101 ia[2] = 5; 102 ia[3] = 8; 103 ia[4] = 10; 104 } 105 PetscCall(MatCreateMPIAdj(comm, 4, 16, ia, ja, NULL, &A)); 106 PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD)); 107 /* 108 Partition the graph of the matrix 109 */ 110 PetscCall(MatPartitioningCreate(comm, &part)); 111 PetscCall(MatPartitioningSetAdjacency(part, A)); 112 PetscCall(MatPartitioningSetType(part, MATPARTITIONINGHIERARCH)); 113 PetscCall(MatPartitioningHierarchicalSetNcoarseparts(part, 2)); 114 PetscCall(MatPartitioningHierarchicalSetNfineparts(part, 2)); 115 PetscCall(MatPartitioningSetFromOptions(part)); 116 /* get new processor owner number of each vertex */ 117 PetscCall(MatPartitioningApply(part, &is)); 118 /* coarse parts */ 119 PetscCall(MatPartitioningHierarchicalGetCoarseparts(part, &coarseparts)); 120 PetscCall(ISView(coarseparts, PETSC_VIEWER_STDOUT_WORLD)); 121 /* fine parts */ 122 PetscCall(MatPartitioningHierarchicalGetFineparts(part, &fineparts)); 123 PetscCall(ISView(fineparts, PETSC_VIEWER_STDOUT_WORLD)); 124 /* partitioning */ 125 PetscCall(ISView(is, PETSC_VIEWER_STDOUT_WORLD)); 126 /* get new global number of each old global number */ 127 PetscCall(ISPartitioningToNumbering(is, &isn)); 128 PetscCall(ISView(isn, PETSC_VIEWER_STDOUT_WORLD)); 129 PetscCall(ISBuildTwoSided(is, NULL, &isrows)); 130 PetscCall(ISView(isrows, PETSC_VIEWER_STDOUT_WORLD)); 131 PetscCall(ISDestroy(&is)); 132 PetscCall(ISDestroy(&coarseparts)); 133 PetscCall(ISDestroy(&fineparts)); 134 PetscCall(ISDestroy(&isrows)); 135 PetscCall(ISDestroy(&isn)); 136 PetscCall(MatPartitioningDestroy(&part)); 137 /* 138 Free work space. All PETSc objects should be destroyed when they 139 are no longer needed. 140 */ 141 PetscCall(MatDestroy(&A)); 142 PetscCall(PetscFinalize()); 143 return 0; 144 } 145 146 /*TEST 147 148 test: 149 nsize: 4 150 requires: parmetis 151 TODO: tests cannot use parmetis because it produces different results on different machines 152 153 TEST*/ 154