\myprogram{{tune\_qnn\_adaptive}}
          {Construct a multiplex with prescribed inter-layer correlations.} 
          {$<$degs1$>$  $<$degs2$>$ $<$mu$>$ $<$eps$>$ $<$beta$>$ [RND|NAT|INV]}

\mydescription{This programs tunes the inter-layer degree correlation
          exponent $\mu$. If we consider two layers of a multiplex,
          and we denote by $k$ the degree of a node on the first layer
          and by $q$ the degree of the same node on the second layers,
          the inter-layer degree correlation function is defined as:
          
          \begin{equation*}
            \overline{q}(k) = \sum_{q'} q' P(q'|k)
          \end{equation*}

           where $\overline{q}(k)$ is the average degree on layer $2$
           of nodes having degree $k$ on layer $1$. 

           The program assumes that we want to set the degree
           correlation function such that:

           \begin{equation*}
           \overline{q}(k) = a k^{\mu}
           \end{equation*}
           
           where the exponent of the power-law function is given by
           the user (it is indeed the parameter \textit{mu}), and
           successively adjusts the pairing between nodes at the two
           layers in order to obtain a correlation function as close
           as possible to the desired one. The files \textit{degs1}
           and \textit{degs2} contain, respectively, the degrees of
           the nodes on the first layer and on the second layer. 
           
           The parameter \textit{eps} is the accuracy of \textit{mu}.
           For instance, if \textit{mu} is set equal to -0.25
           and \textit{eps} is equal to 0.0001, the program stops when
           the configuration of node pairing corresponds to a value of
           the exponent $\mu$ which differs from -0.25 by less than
           0.0001.

          The parameter \textit{beta} is the typical inverse
          temperature of simulated annealing.

          If no other parameter is specified, or if the last parameter
          is \texttt{RND}, the program starts from a random pairing of
          nodes. If the last parameter is \texttt{NAT} then the
          program assumes that the initial pairing is the natural one,
          where the nodes have the same ID on both layers. Finally,
          if \texttt{INV} is specified, the initial pairing is the
          inverse pairing, i.e. the one where node 0 on layer 1 is
          paired with node N-1 on layer 2, and so on.

 }


\myreturn{The program prints on \texttt{stdout} a pairing, i.e. a list
of lines in the format:

\hspace{0.5cm} \textit{IDL1 IDL2}

where \textit{IDL1} is the ID of the node on layer 1 and \textit{IDL2}
is the corresponding ID of the same node on layer 2.
}

\myreference{\refcorrelations}