2:  #include <petscmat.h>
  3:  #include <petsc/private/matorderimpl.h>

  5: /*
  6:     MatGetOrdering_1WD - Find the 1-way dissection ordering of a given matrix.
  7: */
  8: PETSC_INTERN PetscErrorCode MatGetOrdering_1WD(Mat mat,MatOrderingType type,IS *row,IS *col)
  9: {
 11:   PetscInt       i,*mask,*xls,nblks,*xblk,*ls,nrow,*perm;
 12:   const PetscInt *ia,*ja;
 13:   PetscBool      done;

 16:   MatGetRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);
 17:   if (!done) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_SUP,"Cannot get rows for matrix");

 19:   PetscMalloc5(nrow,&mask,nrow+1,&xls,nrow,&ls,nrow+1,&xblk,nrow,&perm);
 20:   SPARSEPACKgen1wd(&nrow,ia,ja,mask,&nblks,xblk,perm,xls,ls);
 21:   MatRestoreRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,NULL,&ia,&ja,&done);

 23:   for (i=0; i<nrow; i++) perm[i]--;

 25:   ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,row);
 26:   ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,col);
 27:   PetscFree5(mask,xls,ls,xblk,perm);
 28:   return(0);
 29: }