Dear all, I think the following message should work. Excuse me for the previous message.
library(spdep) library(rgdal) library(Matrix) nc_sids <- readOGR(system.file("shapes/sids.shp", package = "spData")) adj <- poly2nb(nc_sids) W <- as(nb2mat(adj, style = "B"), "Matrix") Matrix::isSymmetric(W) chol(W) If it's still not working I added a reprex here: https://gist.github.com/agila5/59d3a173df9b1efabe13800f748a2d48 Kind regards Andrea Il giorno mer 29 lug 2020 alle ore 17:19 Roger Bivand <roger.biv...@nhh.no> ha scritto: > Please follow-up in this thread posting in plain text (not HTML). As you > can see below, HTML garbles your message. > > On Wed, 29 Jul 2020, Andrea Gilardi wrote: > > > Dear all, probably I'm missing something obvious but I have a question on > > the matrix built using nb2mat with argument style = "B". More precisely, > I > > don't understand why the following code says that the matrix *W* (which > > should be a binary first-order adjacency matrix) is not symmetric: > > > > > > > > > > > > > > > > > > > > > > > > > > > > *library(spdep)library(rgdal)library(Matrix)# datanc.sids <- > > readOGR(system.file("shapes/sids.shp", package = "spData"))adj <- > > poly2nb(nc.sids)W <- as(nb2mat(adj, style = "B"), > > "Matrix")Matrix::isSymmetric(W)#> [1] FALSEchol(W)#> Error in > > asMethod(object): not a symmetric matrix; consider forceSymmetric() or > > symmpart()* > > > > Kind regards > > Andrea > > > > [[alternative HTML version deleted]] > > > > _______________________________________________ > > R-sig-Geo mailing list > > R-sig-Geo@r-project.org > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > -- > Roger Bivand > Department of Economics, Norwegian School of Economics, > Helleveien 30, N-5045 Bergen, Norway. > voice: +47 55 95 93 55; e-mail: roger.biv...@nhh.no > https://orcid.org/0000-0003-2392-6140 > https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en > [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo