\myprogram{{rank\_occurrence.py}}
          {compute the intersection of two rankings.}  
          {$<$rank1$>$ $<$rank2$>$ $<$increment$>$}

\mydescription{Get two rankings \textit{rank1} and \textit{rank2} 
                   and compute the size of
the \textit{k}-intersection, i.e. the number of elements which are
present in the first k positions of both rankings, as a function
of \textit{k}.  The parameter \textit{increment} determines the
distance between two subsequent values of \textit{k}.

Each input file is a list of node IDs, one per line, where the first
line contains the ID of the highest ranked node.
}

\myreturn{The program prints on \texttt{stdout} a list of lines in the
format:
  
  \hspace{0.5cm} \textit{k num\_k}
  
  where \textit{num\_k} is the number of nodes which are present in
  the first \textit{k} positions of both rankings.}

\myreference{\refcorrelations}