1 static char help[] = "Example of using graph partitioning to partition a graph\n\n"; 2 3 #include <petscmat.h> 4 5 int main(int argc, char **args) 6 { 7 Mat A; 8 MatPartitioning part; 9 IS is; 10 PetscInt r,N = 10, start, end, *vweights; 11 PetscBool set_vweights=PETSC_FALSE,use_edge_weights=PETSC_FALSE; 12 PetscMPIInt rank; 13 MPI_Comm comm; 14 15 PetscFunctionBeginUser; 16 PetscCall(PetscInitialize(&argc, &args, (char*) 0, help)); 17 comm = PETSC_COMM_WORLD; 18 PetscCall(PetscOptionsGetInt(NULL,NULL, "-N", &N, NULL)); 19 PetscCallMPI(MPI_Comm_rank(comm,&rank)); 20 PetscCall(MatCreate(comm, &A)); 21 PetscCall(MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, N, N)); 22 PetscCall(MatSetFromOptions(A)); 23 PetscCall(MatSeqAIJSetPreallocation(A, 3, NULL)); 24 PetscCall(MatMPIAIJSetPreallocation(A, 3, NULL, 2, NULL)); 25 PetscCall(PetscOptionsGetBool(NULL,NULL,"-test_vertex_weights",&set_vweights,NULL)); 26 PetscCall(PetscOptionsGetBool(NULL,NULL,"-test_use_edge_weights",&use_edge_weights,NULL)); 27 /* Create a linear mesh */ 28 PetscCall(MatGetOwnershipRange(A, &start, &end)); 29 if (set_vweights) { 30 PetscCall(PetscMalloc1(end-start,&vweights)); 31 for (r = start; r < end; ++r) 32 vweights[r-start] = rank+1; 33 } 34 for (r = start; r < end; ++r) { 35 if (r == 0) { 36 PetscInt cols[2]; 37 PetscScalar vals[2]; 38 39 cols[0] = r; cols[1] = r+1; 40 vals[0] = 1.0; vals[1] = use_edge_weights? 2.0: 1.0; 41 42 PetscCall(MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES)); 43 } else if (r == N-1) { 44 PetscInt cols[2]; 45 PetscScalar vals[2]; 46 47 cols[0] = r-1; cols[1] = r; 48 vals[0] = use_edge_weights? 3.0:1.0; vals[1] = 1.0; 49 50 PetscCall(MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES)); 51 } else { 52 PetscInt cols[3]; 53 PetscScalar vals[3]; 54 55 cols[0] = r-1; cols[1] = r; cols[2] = r+1; 56 /* ADJ matrix needs to be symmetric */ 57 vals[0] = use_edge_weights? (cols[0]==0? 2.0:5.0):1.0; 58 vals[1] = 1.0; 59 vals[2] = use_edge_weights? (cols[2]==N-1? 3.0:5.0):1.0; 60 61 PetscCall(MatSetValues(A, 1, &r, 3, cols, vals, INSERT_VALUES)); 62 } 63 } 64 PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY)); 65 PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY)); 66 67 PetscCall(MatPartitioningCreate(comm, &part)); 68 PetscCall(MatPartitioningSetAdjacency(part, A)); 69 if (set_vweights) PetscCall(MatPartitioningSetVertexWeights(part,vweights)); 70 if (use_edge_weights) { 71 PetscCall(MatPartitioningSetUseEdgeWeights(part,use_edge_weights)); 72 73 PetscCall(MatPartitioningGetUseEdgeWeights(part,&use_edge_weights)); 74 PetscCheck(use_edge_weights,comm,PETSC_ERR_ARG_INCOMP, "use_edge_weights flag does not setup correctly "); 75 } 76 PetscCall(MatPartitioningSetFromOptions(part)); 77 PetscCall(MatPartitioningApply(part, &is)); 78 PetscCall(ISView(is, PETSC_VIEWER_STDOUT_WORLD)); 79 PetscCall(ISDestroy(&is)); 80 PetscCall(MatPartitioningDestroy(&part)); 81 82 PetscCall(MatDestroy(&A)); 83 PetscCall(PetscFinalize()); 84 return 0; 85 } 86 87 /*TEST 88 89 test: 90 nsize: 3 91 requires: parmetis 92 args: -mat_partitioning_type parmetis 93 94 test: 95 suffix: 2 96 nsize: 3 97 requires: ptscotch 98 args: -mat_partitioning_type ptscotch 99 100 test: 101 suffix: 3 102 nsize: 4 103 requires: party 104 args: -mat_partitioning_type party 105 106 test: 107 suffix: 4 108 nsize: 3 109 requires: chaco 110 args: -mat_partitioning_type chaco 111 112 test: 113 suffix: 5 114 nsize: 3 115 requires: parmetis 116 args: -mat_partitioning_type hierarch -mat_partitioning_hierarchical_nfineparts 3 -mat_partitioning_nparts 10 -N 100 117 118 test: 119 suffix: 6 120 nsize: 3 121 requires: parmetis 122 args: -mat_partitioning_type hierarch -mat_partitioning_hierarchical_nfineparts 3 -mat_partitioning_nparts 10 -N 100 -test_vertex_weights 1 -mat_partitioning_use_edge_weights 1 123 124 test: 125 suffix: 7 126 nsize: 2 127 requires: parmetis 128 args: -mat_partitioning_type hierarch -mat_partitioning_hierarchical_nfineparts 2 -mat_partitioning_nparts 10 -mat_partitioning_hierarchical_fineparttype hierarch -malloc_dump -N 100 -mat_partitioning_improve 1 129 130 test: 131 suffix: 8 132 nsize: 2 133 requires: parmetis 134 args: -mat_partitioning_type parmetis -mat_partitioning_nparts 3 -test_use_edge_weights 1 135 136 test: 137 suffix: 9 138 nsize: 2 139 requires: ptscotch 140 args: -mat_partitioning_type ptscotch -mat_partitioning_nparts 3 -test_use_edge_weights 1 -mat_partitioning_ptscotch_proc_weight 0 141 142 TEST*/ 143