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 ierr = PetscOptionsGetInt(NULL,NULL, "-N", &N, NULL);CHKERRQ(ierr); 25 ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr); 26 ierr = MatCreate(comm, &A);CHKERRQ(ierr); 27 ierr = MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, N, N);CHKERRQ(ierr); 28 ierr = MatSetFromOptions(A);CHKERRQ(ierr); 29 ierr = MatSeqAIJSetPreallocation(A, 3, NULL);CHKERRQ(ierr); 30 ierr = MatMPIAIJSetPreallocation(A, 3, NULL, 2, NULL);CHKERRQ(ierr); 31 ierr = PetscOptionsGetBool(NULL,NULL,"-test_vertex_weights",&set_vweights,NULL);CHKERRQ(ierr); 32 ierr = PetscOptionsGetBool(NULL,NULL,"-test_use_edge_weights",&use_edge_weights,NULL);CHKERRQ(ierr); 33 /* Create a linear mesh */ 34 ierr = MatGetOwnershipRange(A, &start, &end);CHKERRQ(ierr); 35 if (set_vweights) { 36 ierr = PetscMalloc1(end-start,&vweights);CHKERRQ(ierr); 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 ierr = MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES);CHKERRQ(ierr); 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 ierr = MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES);CHKERRQ(ierr); 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 ierr = MatSetValues(A, 1, &r, 3, cols, vals, INSERT_VALUES);CHKERRQ(ierr); 68 } 69 } 70 ierr = MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 71 ierr = MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 72 73 ierr = MatPartitioningCreate(comm, &part);CHKERRQ(ierr); 74 ierr = MatPartitioningSetAdjacency(part, A);CHKERRQ(ierr); 75 if (set_vweights) { 76 ierr = MatPartitioningSetVertexWeights(part,vweights);CHKERRQ(ierr); 77 } 78 if (use_edge_weights) { 79 ierr = MatPartitioningSetUseEdgeWeights(part,use_edge_weights);CHKERRQ(ierr); 80 81 ierr = MatPartitioningGetUseEdgeWeights(part,&use_edge_weights);CHKERRQ(ierr); 82 if (!use_edge_weights) SETERRQ(comm,PETSC_ERR_ARG_INCOMP, "use_edge_weights flag does not setup correctly \n"); 83 } 84 ierr = MatPartitioningSetFromOptions(part);CHKERRQ(ierr); 85 ierr = MatPartitioningApply(part, &is);CHKERRQ(ierr); 86 ierr = ISView(is, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 87 ierr = ISDestroy(&is);CHKERRQ(ierr); 88 ierr = MatPartitioningDestroy(&part);CHKERRQ(ierr); 89 90 ierr = MatDestroy(&A);CHKERRQ(ierr); 91 ierr = PetscFinalize(); 92 return ierr; 93 } 94 95 96 /*TEST 97 98 test: 99 nsize: 3 100 requires: parmetis 101 args: -mat_partitioning_type parmetis 102 103 test: 104 suffix: 2 105 nsize: 3 106 requires: ptscotch 107 args: -mat_partitioning_type ptscotch 108 109 test: 110 suffix: 3 111 nsize: 4 112 requires: party 113 args: -mat_partitioning_type party 114 115 test: 116 suffix: 4 117 nsize: 3 118 requires: chaco 119 args: -mat_partitioning_type chaco 120 121 test: 122 suffix: 5 123 nsize: 3 124 requires: parmetis 125 args: -mat_partitioning_type hierarch -mat_partitioning_hierarchical_nfineparts 3 -mat_partitioning_nparts 10 -N 100 126 127 test: 128 suffix: 6 129 nsize: 3 130 requires: parmetis 131 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 1 132 133 test: 134 suffix: 7 135 nsize: 2 136 requires: parmetis 137 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 1 138 139 test: 140 suffix: 8 141 nsize: 2 142 requires: parmetis 143 args: -mat_partitioning_type parmetis -mat_partitioning_nparts 3 -test_use_edge_weights 1 144 145 test: 146 suffix: 9 147 nsize: 2 148 requires: ptscotch 149 args: -mat_partitioning_type ptscotch -mat_partitioning_nparts 3 -test_use_edge_weights 1 -mat_partitioning_ptscotch_proc_weight 0 150 151 TEST*/ 152