The mixing matrix of a graph gives the density of edges between vertices with different characteristics. The mixing matrix for a given igraph object can be calculated using the following function:   # calculate the mixing matrix of in igraph graph object ‘mygraph’, by some vertex attribute ‘attrib’ # can change the default use.density=FALSE to…

In a previous post, I discussed different approaches to speeding up some loops in data frames. In particular, R data frames provide a simple framework for representing large cohorts of agents in stochastic epidemiological models, such as those representing disease transmission. This approach is much easier and likely faster than trying to implement cohorts of R…

In a previous post we used the web of sexual contacts among characters on the Grey’s Anatomy television show to look at some social network analysis using R. To celebrate the beginning of the new season, Ben Lind has put together a Grey’s Anatomy tutorial on exponential random graph (ERG) models. Who knew popular culture could teach us so much…