1 static char help[] = "Example of using graph partitioning to partition a graph\n\n"; 2 3 /*T 4 Concepts: Mat^mat partitioning 5 Concepts: Mat^image segmentation 6 Processors: n 7 T*/ 8 9 #include <petscmat.h> 10 11 int main(int argc, char **args) 12 { 13 Mat A; 14 MatPartitioning part; 15 IS is; 16 PetscInt r,N = 10, start, end, *vweights; 17 PetscBool set_vweights=PETSC_FALSE,use_edge_weights=PETSC_FALSE; 18 PetscMPIInt rank; 19 MPI_Comm comm; 20 PetscErrorCode ierr; 21 22 ierr = PetscInitialize(&argc, &args, (char*) 0, help);if (ierr) return ierr; 23 comm = PETSC_COMM_WORLD; 24 CHKERRQ(PetscOptionsGetInt(NULL,NULL, "-N", &N, NULL)); 25 CHKERRMPI(MPI_Comm_rank(comm,&rank)); 26 CHKERRQ(MatCreate(comm, &A)); 27 CHKERRQ(MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, N, N)); 28 CHKERRQ(MatSetFromOptions(A)); 29 CHKERRQ(MatSeqAIJSetPreallocation(A, 3, NULL)); 30 CHKERRQ(MatMPIAIJSetPreallocation(A, 3, NULL, 2, NULL)); 31 CHKERRQ(PetscOptionsGetBool(NULL,NULL,"-test_vertex_weights",&set_vweights,NULL)); 32 CHKERRQ(PetscOptionsGetBool(NULL,NULL,"-test_use_edge_weights",&use_edge_weights,NULL)); 33 /* Create a linear mesh */ 34 CHKERRQ(MatGetOwnershipRange(A, &start, &end)); 35 if (set_vweights) { 36 CHKERRQ(PetscMalloc1(end-start,&vweights)); 37 for (r = start; r < end; ++r) 38 vweights[r-start] = rank+1; 39 } 40 for (r = start; r < end; ++r) { 41 if (r == 0) { 42 PetscInt cols[2]; 43 PetscScalar vals[2]; 44 45 cols[0] = r; cols[1] = r+1; 46 vals[0] = 1.0; vals[1] = use_edge_weights? 2.0: 1.0; 47 48 CHKERRQ(MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES)); 49 } else if (r == N-1) { 50 PetscInt cols[2]; 51 PetscScalar vals[2]; 52 53 cols[0] = r-1; cols[1] = r; 54 vals[0] = use_edge_weights? 3.0:1.0; vals[1] = 1.0; 55 56 CHKERRQ(MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES)); 57 } else { 58 PetscInt cols[3]; 59 PetscScalar vals[3]; 60 61 cols[0] = r-1; cols[1] = r; cols[2] = r+1; 62 /* ADJ matrix needs to be symmetric */ 63 vals[0] = use_edge_weights? (cols[0]==0? 2.0:5.0):1.0; 64 vals[1] = 1.0; 65 vals[2] = use_edge_weights? (cols[2]==N-1? 3.0:5.0):1.0; 66 67 CHKERRQ(MatSetValues(A, 1, &r, 3, cols, vals, INSERT_VALUES)); 68 } 69 } 70 CHKERRQ(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY)); 71 CHKERRQ(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY)); 72 73 CHKERRQ(MatPartitioningCreate(comm, &part)); 74 CHKERRQ(MatPartitioningSetAdjacency(part, A)); 75 if (set_vweights) { 76 CHKERRQ(MatPartitioningSetVertexWeights(part,vweights)); 77 } 78 if (use_edge_weights) { 79 CHKERRQ(MatPartitioningSetUseEdgeWeights(part,use_edge_weights)); 80 81 CHKERRQ(MatPartitioningGetUseEdgeWeights(part,&use_edge_weights)); 82 PetscCheck(use_edge_weights,comm,PETSC_ERR_ARG_INCOMP, "use_edge_weights flag does not setup correctly "); 83 } 84 CHKERRQ(MatPartitioningSetFromOptions(part)); 85 CHKERRQ(MatPartitioningApply(part, &is)); 86 CHKERRQ(ISView(is, PETSC_VIEWER_STDOUT_WORLD)); 87 CHKERRQ(ISDestroy(&is)); 88 CHKERRQ(MatPartitioningDestroy(&part)); 89 90 CHKERRQ(MatDestroy(&A)); 91 ierr = PetscFinalize(); 92 return ierr; 93 } 94 95 /*TEST 96 97 test: 98 nsize: 3 99 requires: parmetis 100 args: -mat_partitioning_type parmetis 101 102 test: 103 suffix: 2 104 nsize: 3 105 requires: ptscotch 106 args: -mat_partitioning_type ptscotch 107 108 test: 109 suffix: 3 110 nsize: 4 111 requires: party 112 args: -mat_partitioning_type party 113 114 test: 115 suffix: 4 116 nsize: 3 117 requires: chaco 118 args: -mat_partitioning_type chaco 119 120 test: 121 suffix: 5 122 nsize: 3 123 requires: parmetis 124 args: -mat_partitioning_type hierarch -mat_partitioning_hierarchical_nfineparts 3 -mat_partitioning_nparts 10 -N 100 125 126 test: 127 suffix: 6 128 nsize: 3 129 requires: parmetis 130 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 1 131 132 test: 133 suffix: 7 134 nsize: 2 135 requires: parmetis 136 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 1 137 138 test: 139 suffix: 8 140 nsize: 2 141 requires: parmetis 142 args: -mat_partitioning_type parmetis -mat_partitioning_nparts 3 -test_use_edge_weights 1 143 144 test: 145 suffix: 9 146 nsize: 2 147 requires: ptscotch 148 args: -mat_partitioning_type ptscotch -mat_partitioning_nparts 3 -test_use_edge_weights 1 -mat_partitioning_ptscotch_proc_weight 0 149 150 TEST*/ 151