adjacency-matrix

I want to create a plot showing connections between nodes from an adjacency matrix like the one below. gplot seems like the best tool for this. However, in order to use it, I need to pass the coordinate of each node. The problem is that I don't know where the coordinates should be, I was hoping the function would be capable of figuring out a good layout for me. For example here's my output using the following arbitrary coordinates: A = [1 1 0 0 1 0; 1 0 1 0 1 0; 0 1 0 1 0 0; 0 0 1 0 1 1; 1 1 0 1 0 0; 0 0 0 1 0 0]; crd = [0 1; 1 1; 2 1; 0 2; 1 2; 2 2]; gplot (A, crd, "o-"); Which is hard to

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

My problem is very simple: I need to create an adjacency list/matrix from a list of edges. I have an edge list stored in a csv document with column1 = node1 and column2 = node2 and I would like to convert this to a weighted adjacency list or a weighted adjacency matrix. To be more precise, here's how the data looks like -where the numbers are simply node ids: node1,node2 551,548 510,512 548,553 505,504 510,512 552,543 512,510 512,510 551,548 548,543 543,547 543,548 548,543 548,542 Any tips on how to achieve the conversion from this to a weighted adjacency list/matrix? This is how I resolved to

I want to find the adjacency matrix from a csv file that includes the information as follows: A B 1 2 1 3 1 4 2 5 3 7 and so on. There are 100 nodes but everytime I try to create a matrix and subsequently plot the graph, the error is that it is a non-square matrix. Can somebody help me with the correct code in R? Brian Diggs What you have is an edge list. You can build a graph from that and then covert it to an adjacency matrix: library(igraph) dat <- read.table(text="A B 1 2 1 3 1 4 2 5 3 7", header=TRUE) get.adjacency(graph.edgelist(as.matrix(dat), directed=FALSE)) That gives 7 x 7 sparse

Edit: huge thanks to the users below for great contributions and to Gregor for benchmarking. Say I have a matrix filled with integer values like this... mat <- matrix(1:100, 10, 10) I can create a list of x, y coordinates of each element like this... addresses <- expand.grid(x = 1:10, y = 1:10) Now for each of these coordinates (i.e. for each element in mat) i would like to find the neighboring elements (including diagonals this should make 8 neighbors). I'm sure there is an easy way, can anyone help? What I have tried so far is to loop through and for each element record the neighboring

Hello I understand the concepts of adjacency list and matrix but I am confused as to how to implement them in Python: An algorithm to achieve the following two examples achieve but without knowing the input from the start as they hard code it in their examples: For adjacency list: a, b, c, d, e, f, g, h = range(8) N = [ {b:2, c:1, d:3, e:9, f:4}, # a {c:4, e:3}, # b {d:8}, # c {e:7}, # d {f:5}, # e {c:2, g:2, h:2}, # f {f:1, h:6}, # g {f:9, g:8} # h ] For adjacency matrix: a, b, c, d, e, f, g, h = range(8) _ = float('inf') # a b c d e f g h W = [[0,2,1,3,9,4,_,_], # a [_,0,4,_,3,_,_,_], # b [_