xref: /petsc/src/dm/impls/plex/tests/ex28.c (revision 40badf4fbc550ac1f60bd080eaff6de6d55b946d)
1 static char help[] = "Compare parallel partitioning strategies using matrix graphs\n\n";
2 
3 #include <petscmat.h>
4 
5 int main(int argc, char **args)
6 {
7   MatPartitioning part;
8   IS              partis;
9   Mat             A        = NULL;
10   PetscInt        max      = -1;
11   PetscInt        min      = -1;
12   PetscReal       balance  = 0.0;
13   const PetscInt *ranges  = NULL;
14   char            filein[PETSC_MAX_PATH_LEN];
15   MPI_Comm        comm;
16   PetscMPIInt     size;
17   PetscInt        p;
18   PetscBool       flg;
19   PetscErrorCode  ierr;
20 
21   /*load matrix*/
22   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
23   comm = PETSC_COMM_WORLD;
24   CHKERRMPI(MPI_Comm_size(comm, &size));
25   CHKERRQ(PetscOptionsGetString(NULL,NULL,"-fin",filein,sizeof(filein),&flg));
26   if (flg) {
27     PetscViewer view;
28     CHKERRQ(PetscViewerBinaryOpen(comm,filein,FILE_MODE_READ,&view));
29     CHKERRQ(MatCreate(comm,&A));
30     CHKERRQ(MatLoad(A,view));
31     CHKERRQ(PetscViewerDestroy(&view));
32   }
33 
34   /*partition matrix*/
35   CHKERRQ(MatPartitioningCreate(comm,&part));
36   CHKERRQ(MatPartitioningSetAdjacency(part, A));
37   CHKERRQ(MatPartitioningSetFromOptions(part));
38   CHKERRQ(MatPartitioningApply(part, &partis));
39   CHKERRQ(MatGetOwnershipRanges(A, &ranges));
40   CHKERRQ(MatGetSize(A, &min, NULL));
41   for (p = 0; p < size; ++p) {
42     const PetscInt partsize = ranges[p+1]-ranges[p];
43 
44     max = PetscMax(max, partsize);
45     min = PetscMin(min, partsize);
46   }
47   balance = ((PetscReal) max)/min;
48   CHKERRQ(PetscPrintf(comm, "ranges: "));
49   for (p = 0; p <= size; ++p) {
50     if (p > 0) CHKERRQ(PetscPrintf(comm, ", "));
51     CHKERRQ(PetscPrintf(comm, "%D", ranges[p]));
52   }
53   CHKERRQ(PetscPrintf(comm, "\n"));
54   CHKERRQ(PetscPrintf(comm, "max:%.0lf min:%.0lf balance:%.11lf\n", (double) max,(double) min,(double) balance));
55   CHKERRQ(PetscObjectViewFromOptions((PetscObject)partis,NULL,"-partition_view"));
56   CHKERRQ(MatPartitioningDestroy(&part));
57   CHKERRQ(ISDestroy(&partis));
58   CHKERRQ(MatDestroy(&A));
59   ierr = PetscFinalize();
60   return ierr;
61 
62 }
63