Actual source code: sprcm.c

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

      5: /*
      6:     MatGetOrdering_RCM - Find the Reverse Cuthill-McKee ordering of a given matrix.
      7: */
      8: PETSC_INTERN PetscErrorCode MatGetOrdering_RCM(Mat mat,MatOrderingType type,IS *row,IS *col)
      9: {
     10:   PetscInt       i,*mask,*xls,nrow,*perm;
     11:   const PetscInt *ia,*ja;
     12:   PetscBool      done;

     14:   MatGetRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);

     17:   PetscMalloc3(nrow,&mask,nrow,&perm,2*nrow,&xls);
     18:   SPARSEPACKgenrcm(&nrow,ia,ja,perm,mask,xls);
     19:   MatRestoreRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,NULL,&ia,&ja,&done);

     21:   /* shift because Sparsepack indices start at one */
     22:   for (i=0; i<nrow; i++) perm[i]--;
     23:   ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,row);
     24:   ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,col);
     25:   PetscFree3(mask,perm,xls);
     26:   return 0;
     27: }