n the network. In many systems, we can 
% find a partition of nodes into specific communities or modules.  
% This modularity metric can be expressed for a bipartite network as:
% <latex>
% \begin{equation}
% Q_b = \frac{1}{E} \sum_{ij} \left( B_{ij} - \frac{k_i d_j}{E} \right) \delta(g_i,h_j),
% \end{equation}
% </latex>
% where @B_ij@ is the element in the bipartite matrix representing a link
% (1)
% or no link (0) between nodes @i@ and @j@, @g_i@ and @h_i@ are the module indexes of nodes @i@ (t