David Winsemius <dwinsem...@comcast.net> writes: > On Jul 11, 2011, at 3:28 PM, Thomas S. Dye wrote: > >> Aloha all, >> >> I have an adjacency matrix for an acyclic digraph that contains >> transitive relations, e.g. (u,v), (v,w), (u,w). I want a DAG with >> only >> intransitive relations. Can someone point me to an R function that >> will >> take my adjacency matrix and give me back one with only intransitive >> relations? In the example, I'd like to get rid of (u,w) and keep >> (u,v) >> and (v,w). > > I'm needing to guess at what sort of code you are using but assuming > this is a square matrix: > > require(ggm) > dag <- DAG(y ~ x, x ~ z, u~z) >> which(dag != t(dag), arr.ind=TRUE) > row col > x 2 1 > y 1 2 > z 3 2 > x 2 3 > u 4 3 > z 3 4 >
Aloha David, Thanks for this suggestion. I don't think it does what I want. Sorry if I wasn't precise. The graph theory language is new to me. What I'm looking for is a function that gets rid of transitive relations, like so: tdye> dag <- DAG(v ~ u, w ~ v, w ~ u) tdye> dag v u w v 0 0 1 u 1 0 1 w 0 0 0 tdye> dag[2,3] <- 0 tdye> dag v u w v 0 0 1 u 1 0 0 w 0 0 0 All the best, Tom >> All the best, >> Tom >> -- >> Thomas S. Dye >> http://www.tsdye.com >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > David Winsemius, MD > West Hartford, CT > -- Thomas S. Dye http://www.tsdye.com ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
