1: static char help[] = "Example of using graph partitioning to partition a graph\n\n";

  3: #include <petscmat.h>

  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;

 15:   PetscInitialize(&argc, &args, (char*) 0, help);
 16:   comm = PETSC_COMM_WORLD;
 17:   PetscOptionsGetInt(NULL,NULL, "-N", &N, NULL);
 18:   MPI_Comm_rank(comm,&rank);
 19:   MatCreate(comm, &A);
 20:   MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, N, N);
 21:   MatSetFromOptions(A);
 22:   MatSeqAIJSetPreallocation(A, 3, NULL);
 23:   MatMPIAIJSetPreallocation(A, 3, NULL, 2, NULL);
 24:   PetscOptionsGetBool(NULL,NULL,"-test_vertex_weights",&set_vweights,NULL);
 25:   PetscOptionsGetBool(NULL,NULL,"-test_use_edge_weights",&use_edge_weights,NULL);
 26:   /* Create a linear mesh */
 27:   MatGetOwnershipRange(A, &start, &end);
 28:   if (set_vweights) {
 29:     PetscMalloc1(end-start,&vweights);
 30:     for (r = start; r < end; ++r)
 31:       vweights[r-start] = rank+1;
 32:   }
 33:   for (r = start; r < end; ++r) {
 34:     if (r == 0) {
 35:       PetscInt    cols[2];
 36:       PetscScalar vals[2];

 38:       cols[0] = r;   cols[1] = r+1;
 39:       vals[0] = 1.0; vals[1] = use_edge_weights? 2.0: 1.0;

 41:       MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES);
 42:     } else if (r == N-1) {
 43:       PetscInt    cols[2];
 44:       PetscScalar vals[2];

 46:       cols[0] = r-1; cols[1] = r;
 47:       vals[0] = use_edge_weights? 3.0:1.0; vals[1] = 1.0;

 49:       MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES);
 50:     } else {
 51:       PetscInt    cols[3];
 52:       PetscScalar vals[3];

 54:       cols[0] = r-1; cols[1] = r;   cols[2] = r+1;
 55:       /* ADJ matrix needs to be symmetric */
 56:       vals[0] = use_edge_weights? (cols[0]==0? 2.0:5.0):1.0;
 57:       vals[1] = 1.0;
 58:       vals[2] = use_edge_weights? (cols[2]==N-1? 3.0:5.0):1.0;

 60:       MatSetValues(A, 1, &r, 3, cols, vals, INSERT_VALUES);
 61:     }
 62:   }
 63:   MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY);
 64:   MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY);

 66:   MatPartitioningCreate(comm, &part);
 67:   MatPartitioningSetAdjacency(part, A);
 68:   if (set_vweights) {
 69:     MatPartitioningSetVertexWeights(part,vweights);
 70:   }
 71:   if (use_edge_weights) {
 72:     MatPartitioningSetUseEdgeWeights(part,use_edge_weights);

 74:     MatPartitioningGetUseEdgeWeights(part,&use_edge_weights);
 76:   }
 77:   MatPartitioningSetFromOptions(part);
 78:   MatPartitioningApply(part, &is);
 79:   ISView(is, PETSC_VIEWER_STDOUT_WORLD);
 80:   ISDestroy(&is);
 81:   MatPartitioningDestroy(&part);

 83:   MatDestroy(&A);
 84:   PetscFinalize();
 85:   return 0;
 86: }

 88: /*TEST

 90:    test:
 91:       nsize: 3
 92:       requires: parmetis
 93:       args: -mat_partitioning_type parmetis

 95:    test:
 96:       suffix: 2
 97:       nsize: 3
 98:       requires: ptscotch
 99:       args: -mat_partitioning_type ptscotch

101:    test:
102:       suffix: 3
103:       nsize: 4
104:       requires: party
105:       args: -mat_partitioning_type party

107:    test:
108:       suffix: 4
109:       nsize: 3
110:       requires: chaco
111:       args: -mat_partitioning_type chaco

113:    test:
114:       suffix: 5
115:       nsize: 3
116:       requires: parmetis
117:       args: -mat_partitioning_type hierarch -mat_partitioning_hierarchical_nfineparts 3 -mat_partitioning_nparts 10 -N 100

119:    test:
120:       suffix: 6
121:       nsize: 3
122:       requires: parmetis
123:       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

125:    test:
126:       suffix: 7
127:       nsize: 2
128:       requires: parmetis
129:       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

131:    test:
132:       suffix: 8
133:       nsize: 2
134:       requires: parmetis
135:       args: -mat_partitioning_type parmetis -mat_partitioning_nparts 3 -test_use_edge_weights 1

137:    test:
138:       suffix: 9
139:       nsize: 2
140:       requires: ptscotch
141:       args: -mat_partitioning_type ptscotch -mat_partitioning_nparts 3 -test_use_edge_weights 1 -mat_partitioning_ptscotch_proc_weight 0

143: TEST*/