The lasso is used to determine which edges are present in a topic graph. The original R code was written by David M. Blei and co-authors and is available together with the C code for fitting the CTM.
build_graph(x, lambda, and = TRUE)Object of class "CTM".
Numeric in \([0,1]\) indicating the relative bound on the L1-norm of the parameters.
Logical; if TRUE the graph is computed by taking the
intersection of the neighbors, otherwise the union is determined.
Returns an adjacency matrix for the topics versus topics graph.
Blei D.M., Lafferty J.D. (2007). A Correlated Topic Model of Science. The Annals of Applied Statistics, 1(1), 17--35.