Functional cartography of complex metabolic networks

Abstract

Functional cartography of complex metabolic networks Care has to be taken with equation one; the 2L in it can be very misleading. When implementing the measure I first ended up with very strange results and only looking through the references (esp. Newman, Fast algorithm for detecting community structure in networks) helped. It becomes clearer when you think about the statement "A good partition of a network into modules must comprise many within-module links and as few as possible between-module links. Equation (1) addresses this diffiulty by imposing that M=0 if nodes are placed at random into modules or if all nodes are in the same cluster.". The latter is not true if you naively implement this as putting the whole network into one module leads to: l_s = d_s implying [l_s / L - (d_s / 2L)^2]= [1 - 1/4 * 1]= 0.75 !!!!!!!!!!!!!