I have a sample code in R as follows:
library(igraph)
rm(list=ls())
dat=read.csv(file.choose(),header=TRUE,row.names=1,check.names=T) # read .csv file
m=as.matrix(dat)
net=graph.adjacency(adjmatrix=m,mode="undirected",weighted=TRUE,diag=FALSE)
where I used csv file as input which contain following data:
23732 23778 23824 23871 58009 58098 58256
23732 0 8 0 1 0 10 0
23778 8 0 1 15 0 1 0
23824 0 1 0 0 0 0 0
23871 1 15 0 0 1 5 0
58009 0 0 0 1 0 7 0
58098 10 1 0 5 7 0 1
58256 0 0 0 0 0 1 0
After this I used following command to check weight values:
E(net)$weight
Expected output is somewhat like this:
> E(net)$weight
[1] 8 1 10 1 15 1 1 5 7 1
But I'm getting weird values (and every time different):
> E(net)$weight
[1] 2.121996e-314 2.121996e-313 1.697597e-313 1.291034e-57 1.273197e-312 5.092790e-313 2.121996e-314 2.121996e-314 6.320627e-316 2.121996e-314 1.273197e-312 2.121996e-313
[13] 8.026755e-316 9.734900e-72 1.273197e-312 8.027076e-316 6.320491e-316 8.190221e-316 5.092790e-313 1.968065e-62 6.358638e-316
I'm unable to find where and what I am doing wrong? Please help me to get the correct expected result and also please tell me why is this weird output and that too every time different when I run it.??
Thanks, Nitin
The problem seems to be due to the data-type of the matrix elements. graph.adjacency expects elements of type numeric. Not sure if its a bug.
After you do,
m <- as.matrix(dat)
set its mode to numeric by:
mode(m) <- "numeric"
And then do:
net <- graph.adjacency(m, mode = "undirected", weighted = TRUE, diag = FALSE)
> E(net)$weight
[1] 8 1 10 1 15 1 1 5 7 1
Just a small working example below, much clearer than CSV input.
library('igraph');
adjm1<-matrix(sample(0:1,100,replace=TRUE,prob=c(0.9,01)),nc=10);
g1<-graph.adjacency(adjm1);
plot(g1)
P.s. ?graph.adjacency has a lot of good examples (remember to run library('igraph')).
Related threads
来源：https://stackoverflow.com/questions/14332233/using-graph-adjacency-in-r