Hi, thank you Tamas for your response. The bipartite graph that I am using is not directed.
If I understand your answer correctly on how to calculate density, then, the code above might be wrong, because it says # Number of top and bottom nodes top<-length(V(g)[type==FALSE]) bottom<-length(V(g)[type==TRUE]) # Number of edges m<-ecount(g) # Mean degree for top and bottom nodes ktop<-m/top kbottom<-m/bottom # Density for bipartite network bidens<-m/(top*bottom) So, it takes the actual existing number of edges in the bipartite graph and divides it by the product of the number of nodes for each type. Based on your described ratio, it seems to miss the total number of possible edges between the top and bottom vertices, right? In my case and as an example, we have 11 "top" vertices and 17 "bottom" vertices and the number of edges (m) is 215 (because in this graph, there can be multipe edges between a top and a bottom vertice). If I take the numbers and calculate the density in the following way 215/(11*17), I get 1.15. So, is there anything missing in the calculation or could the multiple edges in the network be the problem here? And how could it be solved? Best wishes, Stefan Am 06.06.2017 um 20:34 schrieb Tamas Nepusz: > > The suggested code works out and I also checked the named > reference for > further information, but I couldn't find anything about the ratio of > bipartite network density. It either doesn't seem to be the 0-1 > ratio of > one-mode networks or I did something wrong, because I get results > about > 1.0 for the 2-mode-networks? > > You are probably doing something wrong because the measure should be > between 0 and 1. It is actually simply the ratio of the total number > of edges and the total number of _possible_ edges between the "top" > and the "bottom" vertices. If you get a result close to 1.0, it means > that almost all of the possible edges between the top and the bottom > vertices are present -- assuming that there are no edges between > top-top or bottom-bottom, which should be the case anyway if it is a > bipartite network. > > One possible catch is if your network is directed; in that case, you > should multiply the denominator of the fraction (i.e. the number of > possible edges) by 2. > > T. > > > _______________________________________________ > igraph-help mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/igraph-help -- Stefan Wallaschek Visting PhD fellow at School of Politics and International Relations (SPIRe) University College Dublin -- [email protected] PhD Fellow Bremen International Graduate School of Social Sciences (BIGSSS)/ University of Bremen Mary-Somerville-Straße 9 P.O. Box 33 04 40 28359 Bremen (Germany) https://www.bigsss-bremen.de/people/phd-fellows/stefan-wallaschek Twitter: https://twitter.com/s_wallaschek
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