xref: /petsc/src/dm/impls/plex/tests/ex28.c (revision 8ebe3e4e9e00d86ece2e9fcd0cc84910b0ad437c)
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   ierr = MPI_Comm_size(comm, &size);CHKERRMPI(ierr);
25   ierr = PetscOptionsGetString(NULL,NULL,"-fin",filein,sizeof(filein),&flg);CHKERRQ(ierr);
26   if (flg) {
27     PetscViewer view;
28     ierr = PetscViewerBinaryOpen(comm,filein,FILE_MODE_READ,&view);CHKERRQ(ierr);
29     ierr = MatCreate(comm,&A);CHKERRQ(ierr);
30     ierr = MatLoad(A,view);CHKERRQ(ierr);
31     ierr = PetscViewerDestroy(&view);CHKERRQ(ierr);
32   }
33 
34   /*partition matrix*/
35   ierr = MatPartitioningCreate(comm,&part);CHKERRQ(ierr);
36   ierr = MatPartitioningSetAdjacency(part, A);CHKERRQ(ierr);
37   ierr = MatPartitioningSetFromOptions(part);CHKERRQ(ierr);
38   ierr = MatPartitioningApply(part, &partis);CHKERRQ(ierr);
39   ierr = MatGetOwnershipRanges(A, &ranges);CHKERRQ(ierr);
40   ierr = MatGetSize(A, &min, NULL);CHKERRQ(ierr);
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   ierr = PetscPrintf(comm, "ranges: ");CHKERRQ(ierr);
49   for (p = 0; p <= size; ++p) {
50     if (p > 0) {ierr = PetscPrintf(comm, ", ");CHKERRQ(ierr);}
51     ierr = PetscPrintf(comm, "%D", ranges[p]);CHKERRQ(ierr);
52   }
53   ierr = PetscPrintf(comm, "\n");CHKERRQ(ierr);
54   ierr = PetscPrintf(comm, "max:%.0lf min:%.0lf balance:%.11lf\n", (double) max,(double) min,(double) balance);CHKERRQ(ierr);
55   ierr = PetscObjectViewFromOptions((PetscObject)partis,NULL,"-partition_view");CHKERRQ(ierr);
56   ierr = MatPartitioningDestroy(&part);CHKERRQ(ierr);
57   ierr = ISDestroy(&partis);CHKERRQ(ierr);
58   ierr = MatDestroy(&A);CHKERRQ(ierr);
59   ierr = PetscFinalize();
60   return ierr;
61 
62 }
63