column            624 ompi/mca/coll/base/coll_base_topo.c         int column;
column            626 ompi/mca/coll/base/coll_base_topo.c             column = (srank-1)/maxchainlen;
column            627 ompi/mca/coll/base/coll_base_topo.c             head = 1+column*maxchainlen;
column            630 ompi/mca/coll/base/coll_base_topo.c             column = mark + (srank-1-mark*maxchainlen)/(maxchainlen-1);
column            631 ompi/mca/coll/base/coll_base_topo.c             head = mark*maxchainlen+1+(column-mark)*(maxchainlen-1);