Actual source code: ex11.c
petsc-3.13.6 2020-09-29
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      2: static char help[] = "Tests MatMeshToDual()\n\n";

      4: /*T
      5:    Concepts: Mat^mesh partitioning
      6:    Processors: n
      7: T*/

      9: /*
     10:   Include "petscmat.h" so that we can use matrices.
     11:   automatically includes:
     12:      petscsys.h       - base PETSc routines   petscvec.h    - vectors
     13:      petscmat.h    - matrices
     14:      petscis.h     - index sets            petscviewer.h - viewers
     15: */
     16:  #include <petscmat.h>

     18: int main(int argc,char **args)
     19: {
     20:   Mat             mesh,dual;
     21:   PetscErrorCode  ierr;
     22:   PetscInt        Nvertices = 6;       /* total number of vertices */
     23:   PetscInt        ncells    = 2;       /* number cells on this process */
     24:   PetscInt        *ii,*jj;
     25:   PetscMPIInt     size,rank;
     26:   MatPartitioning part;
     27:   IS              is;

     29:   PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
     30:   MPI_Comm_size(MPI_COMM_WORLD,&size);
     31:   if (size != 2) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"This example is for exactly two processes");
     32:   MPI_Comm_rank(MPI_COMM_WORLD,&rank);

     34:   PetscMalloc1(3,&ii);
     35:   PetscMalloc1(6,&jj);
     36:   ii[0] = 0; ii[1] = 3; ii[2] = 6;
     37:   if (!rank) {
     38:     jj[0] = 0; jj[1] = 1; jj[2] = 2; jj[3] = 1; jj[4] = 2; jj[5] = 3;
     39:   } else {
     40:     jj[0] = 1; jj[1] = 4; jj[2] = 5; jj[3] = 1; jj[4] = 3; jj[5] = 5;
     41:   }
     42:   MatCreateMPIAdj(MPI_COMM_WORLD,ncells,Nvertices,ii,jj,NULL,&mesh);
     43:   MatMeshToCellGraph(mesh,2,&dual);
     44:   MatView(dual,PETSC_VIEWER_STDOUT_WORLD);

     46:   MatPartitioningCreate(MPI_COMM_WORLD,&part);
     47:   MatPartitioningSetAdjacency(part,dual);
     48:   MatPartitioningSetFromOptions(part);
     49:   MatPartitioningApply(part,&is);
     50:   ISView(is,PETSC_VIEWER_STDOUT_WORLD);
     51:   ISDestroy(&is);
     52:   MatPartitioningDestroy(&part);

     54:   MatDestroy(&mesh);
     55:   MatDestroy(&dual);
     56:   PetscFinalize();
     57:   return ierr;
     58: }

     64: /*TEST

     66:    build:
     67:      requires: parmetis

     69:    test:
     70:       nsize: 2
     71:       requires: parmetis

     73: TEST*/