xref: /petsc/src/mat/tutorials/ex15.c (revision 327415f76d85372a4417cf1aaa14db707d4d6c04)
1c4762a1bSJed Brown static char help[] = "Example of using graph partitioning to partition a graph\n\n";
2c4762a1bSJed Brown 
3c4762a1bSJed Brown #include <petscmat.h>
4c4762a1bSJed Brown 
5c4762a1bSJed Brown int main(int argc, char **args)
6c4762a1bSJed Brown {
7c4762a1bSJed Brown   Mat             A;
8c4762a1bSJed Brown   MatPartitioning part;
9c4762a1bSJed Brown   IS              is;
10c4762a1bSJed Brown   PetscInt        r,N = 10, start, end, *vweights;
11c4762a1bSJed Brown   PetscBool       set_vweights=PETSC_FALSE,use_edge_weights=PETSC_FALSE;
12c4762a1bSJed Brown   PetscMPIInt     rank;
13c4762a1bSJed Brown   MPI_Comm        comm;
14c4762a1bSJed Brown 
15*327415f7SBarry Smith   PetscFunctionBeginUser;
169566063dSJacob Faibussowitsch   PetscCall(PetscInitialize(&argc, &args, (char*) 0, help));
17c4762a1bSJed Brown   comm = PETSC_COMM_WORLD;
189566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL,NULL, "-N", &N, NULL));
199566063dSJacob Faibussowitsch   PetscCallMPI(MPI_Comm_rank(comm,&rank));
209566063dSJacob Faibussowitsch   PetscCall(MatCreate(comm, &A));
219566063dSJacob Faibussowitsch   PetscCall(MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, N, N));
229566063dSJacob Faibussowitsch   PetscCall(MatSetFromOptions(A));
239566063dSJacob Faibussowitsch   PetscCall(MatSeqAIJSetPreallocation(A, 3, NULL));
249566063dSJacob Faibussowitsch   PetscCall(MatMPIAIJSetPreallocation(A, 3, NULL, 2, NULL));
259566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetBool(NULL,NULL,"-test_vertex_weights",&set_vweights,NULL));
269566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetBool(NULL,NULL,"-test_use_edge_weights",&use_edge_weights,NULL));
27c4762a1bSJed Brown   /* Create a linear mesh */
289566063dSJacob Faibussowitsch   PetscCall(MatGetOwnershipRange(A, &start, &end));
29c4762a1bSJed Brown   if (set_vweights) {
309566063dSJacob Faibussowitsch     PetscCall(PetscMalloc1(end-start,&vweights));
31c4762a1bSJed Brown     for (r = start; r < end; ++r)
32c4762a1bSJed Brown       vweights[r-start] = rank+1;
33c4762a1bSJed Brown   }
34c4762a1bSJed Brown   for (r = start; r < end; ++r) {
35c4762a1bSJed Brown     if (r == 0) {
36c4762a1bSJed Brown       PetscInt    cols[2];
37c4762a1bSJed Brown       PetscScalar vals[2];
38c4762a1bSJed Brown 
39c4762a1bSJed Brown       cols[0] = r;   cols[1] = r+1;
40c4762a1bSJed Brown       vals[0] = 1.0; vals[1] = use_edge_weights? 2.0: 1.0;
41c4762a1bSJed Brown 
429566063dSJacob Faibussowitsch       PetscCall(MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES));
43c4762a1bSJed Brown     } else if (r == N-1) {
44c4762a1bSJed Brown       PetscInt    cols[2];
45c4762a1bSJed Brown       PetscScalar vals[2];
46c4762a1bSJed Brown 
47c4762a1bSJed Brown       cols[0] = r-1; cols[1] = r;
48c4762a1bSJed Brown       vals[0] = use_edge_weights? 3.0:1.0; vals[1] = 1.0;
49c4762a1bSJed Brown 
509566063dSJacob Faibussowitsch       PetscCall(MatSetValues(A, 1, &r, 2, cols, vals, INSERT_VALUES));
51c4762a1bSJed Brown     } else {
52c4762a1bSJed Brown       PetscInt    cols[3];
53c4762a1bSJed Brown       PetscScalar vals[3];
54c4762a1bSJed Brown 
55c4762a1bSJed Brown       cols[0] = r-1; cols[1] = r;   cols[2] = r+1;
56c4762a1bSJed Brown       /* ADJ matrix needs to be symmetric */
57c4762a1bSJed Brown       vals[0] = use_edge_weights? (cols[0]==0? 2.0:5.0):1.0;
58c4762a1bSJed Brown       vals[1] = 1.0;
59c4762a1bSJed Brown       vals[2] = use_edge_weights? (cols[2]==N-1? 3.0:5.0):1.0;
60c4762a1bSJed Brown 
619566063dSJacob Faibussowitsch       PetscCall(MatSetValues(A, 1, &r, 3, cols, vals, INSERT_VALUES));
62c4762a1bSJed Brown     }
63c4762a1bSJed Brown   }
649566063dSJacob Faibussowitsch   PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
659566063dSJacob Faibussowitsch   PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
66c4762a1bSJed Brown 
679566063dSJacob Faibussowitsch   PetscCall(MatPartitioningCreate(comm, &part));
689566063dSJacob Faibussowitsch   PetscCall(MatPartitioningSetAdjacency(part, A));
691baa6e33SBarry Smith   if (set_vweights) PetscCall(MatPartitioningSetVertexWeights(part,vweights));
70c4762a1bSJed Brown   if (use_edge_weights) {
719566063dSJacob Faibussowitsch     PetscCall(MatPartitioningSetUseEdgeWeights(part,use_edge_weights));
72c4762a1bSJed Brown 
739566063dSJacob Faibussowitsch     PetscCall(MatPartitioningGetUseEdgeWeights(part,&use_edge_weights));
7428b400f6SJacob Faibussowitsch     PetscCheck(use_edge_weights,comm,PETSC_ERR_ARG_INCOMP, "use_edge_weights flag does not setup correctly ");
75c4762a1bSJed Brown   }
769566063dSJacob Faibussowitsch   PetscCall(MatPartitioningSetFromOptions(part));
779566063dSJacob Faibussowitsch   PetscCall(MatPartitioningApply(part, &is));
789566063dSJacob Faibussowitsch   PetscCall(ISView(is, PETSC_VIEWER_STDOUT_WORLD));
799566063dSJacob Faibussowitsch   PetscCall(ISDestroy(&is));
809566063dSJacob Faibussowitsch   PetscCall(MatPartitioningDestroy(&part));
81c4762a1bSJed Brown 
829566063dSJacob Faibussowitsch   PetscCall(MatDestroy(&A));
839566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
84b122ec5aSJacob Faibussowitsch   return 0;
85c4762a1bSJed Brown }
86c4762a1bSJed Brown 
87c4762a1bSJed Brown /*TEST
88c4762a1bSJed Brown 
89c4762a1bSJed Brown    test:
90c4762a1bSJed Brown       nsize: 3
91c4762a1bSJed Brown       requires: parmetis
92c4762a1bSJed Brown       args: -mat_partitioning_type parmetis
93c4762a1bSJed Brown 
94c4762a1bSJed Brown    test:
95c4762a1bSJed Brown       suffix: 2
96c4762a1bSJed Brown       nsize: 3
97c4762a1bSJed Brown       requires: ptscotch
98c4762a1bSJed Brown       args: -mat_partitioning_type ptscotch
99c4762a1bSJed Brown 
100c4762a1bSJed Brown    test:
101c4762a1bSJed Brown       suffix: 3
102c4762a1bSJed Brown       nsize: 4
103c4762a1bSJed Brown       requires: party
104c4762a1bSJed Brown       args: -mat_partitioning_type party
105c4762a1bSJed Brown 
106c4762a1bSJed Brown    test:
107c4762a1bSJed Brown       suffix: 4
108c4762a1bSJed Brown       nsize: 3
109c4762a1bSJed Brown       requires: chaco
110c4762a1bSJed Brown       args: -mat_partitioning_type chaco
111c4762a1bSJed Brown 
112c4762a1bSJed Brown    test:
113c4762a1bSJed Brown       suffix: 5
114c4762a1bSJed Brown       nsize: 3
115c4762a1bSJed Brown       requires: parmetis
116c4762a1bSJed Brown       args: -mat_partitioning_type hierarch -mat_partitioning_hierarchical_nfineparts 3 -mat_partitioning_nparts 10 -N 100
117c4762a1bSJed Brown 
118c4762a1bSJed Brown    test:
119c4762a1bSJed Brown       suffix: 6
120c4762a1bSJed Brown       nsize: 3
121c4762a1bSJed Brown       requires: parmetis
122c4762a1bSJed Brown       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
123c4762a1bSJed Brown 
124c4762a1bSJed Brown    test:
125c4762a1bSJed Brown       suffix: 7
126c4762a1bSJed Brown       nsize: 2
127c4762a1bSJed Brown       requires: parmetis
128c4762a1bSJed Brown       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
129c4762a1bSJed Brown 
130c4762a1bSJed Brown    test:
131c4762a1bSJed Brown       suffix: 8
132c4762a1bSJed Brown       nsize: 2
133c4762a1bSJed Brown       requires: parmetis
134c4762a1bSJed Brown       args: -mat_partitioning_type parmetis -mat_partitioning_nparts 3 -test_use_edge_weights 1
135c4762a1bSJed Brown 
136c4762a1bSJed Brown    test:
137c4762a1bSJed Brown       suffix: 9
138c4762a1bSJed Brown       nsize: 2
139c4762a1bSJed Brown       requires: ptscotch
140c4762a1bSJed Brown       args: -mat_partitioning_type ptscotch -mat_partitioning_nparts 3 -test_use_edge_weights 1 -mat_partitioning_ptscotch_proc_weight 0
141c4762a1bSJed Brown 
142c4762a1bSJed Brown TEST*/
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