I just updated spdep and I see that as.spam.listw works. Below is
sessionInfo
Furthermore, it may be straightforward to condense the adjacency
matrix *before* converting to graph which may help a little bit. You
can profile the code and see which part needs speeding up.
library(spdep)
library(igraph)
x=matrix(c(0,1,0,0,0,
0,1,1,0,0,
0,0,0,0,0,
0,0,0,1,0,
0,0,0,1,0),nrow=5)
a <- as.spam.listw(nb2listw(cell2nb(nrow(x),ncol(x),torus=T),
style="B"))
ind <- which(x>0)
b <- a[ind, ind]
g1 <- graph.adjacency(b)
clusters(g1)$no
---
R version 2.11.1 (2010-05-31)
i386-apple-darwin9.8.0
locale:
[1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils
[5] datasets methods base
other attached packages:
[1] igraph_0.5.3 spam_0.22-0
[3] spdep_0.5-11 coda_0.13-5
[5] deldir_0.0-12 maptools_0.7-34
[7] foreign_0.8-40 nlme_3.1-96
[9] MASS_7.3-6 Matrix_0.999375-39
[11] lattice_0.18-8 boot_1.2-42
[13] sp_0.9-64
loaded via a namespace (and not attached):
[1] grid_2.11.1 tools_2.11.1
Nikhil Kaza
Asst. Professor,
City and Regional Planning
University of North Carolina
nikhil.l...@gmail.com
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