R igraph cluster nodes with the same colour (feature) - r

# example data
library(igraph)
links <- cbind.data.frame(from = rep("A", 6),
to = LETTERS[1:6],
weight = rep((1:3), each =2))
nodes <- nodes <- cbind.data.frame(id = LETTERS[1:6],
feature = rep((1:3), each =2))
net <- graph_from_data_frame(d = links, vertices = nodes, directed = T)
V(net)$color <- V(net)$feature
plot(net, vertex.size=30, edge.arrow.size = 0)
This is what I get:
What I want is to cluster the same colored nodes together, something similar as shown in the figure below. How can I do it?

Maybe the option mark.groups in plot could help
plot(net,mark.groups = split(V(net)$name,V(net)$color))
which gives

Related

Overriding "Non-Existent Components" in a Loop

I have the following network graph:
library(tidyverse)
library(igraph)
set.seed(123)
n=15
data = tibble(d = paste(1:n))
relations = tibble(
from = sample(data$d),
to = lead(from, default=from[1]),
)
graph = graph_from_data_frame(relations, directed=T, vertices = data)
V(graph)$color <- ifelse(data$d == relations$from[1], "red", "orange")
plot(graph, layout=layout.circle, edge.arrow.size = 0.2)
I learned how to remove all the "edges" in this graph:
g <- graph-E(graph)
plot(g)
Now, I am trying to do this same thing, but using a "loop" instead:
for (i in 1:15)
for (j in 1:15) {
graph <- graph - edge(paste0(i, "|", j))
}
But I think the problem is that the above code is trying to delete "edges" that exist, and this code does not have the ability to "skip" (override) an instance when it is commanded to delete a non-existing edge:
Error in delete_edges(e1, unlist(e2, recursive = FALSE)) :
At iterators.c:1828 : Cannot create iterator, invalid edge id, Invalid vertex id
Is there a way to instruct this "loop" to "skip" every instances where two edges do not have a connection and to continue until the loop is done?
Thank you!
I don't know why you want to run a for loop, but please find below a possible solution using the as_edgelist() function from the igraph library.
Reprex
Your data
library(igraph)
library(dplyr)
set.seed(123)
n=15
data = tibble(d = paste(1:n))
relations = tibble(
from = sample(data$d),
to = lead(from, default=from[1]),
)
graph = graph_from_data_frame(relations, directed=T, vertices = data)
V(graph)$color <- ifelse(data$d == relations$from[1], "red", "orange")
plot(graph, layout=layout.circle, edge.arrow.size = 0.2)
Suggested code
edgelist <- as_edgelist(graph, names = TRUE)
for (i in 1:15) {
graph <- graph - edge(paste0(edgelist[i,1], "|", edgelist[i,2]))
}
plot(graph)
Created on 2022-02-24 by the reprex package (v2.0.1)

igraph in R: Arrange the same coloured nodes next to each other [duplicate]

This question already has an answer here:
(igraph) Grouped layout based on attribute
(1 answer)
Closed 2 years ago.
My example:
library(igraph)
links <- cbind.data.frame(from = rep("A", 6),
to = LETTERS[1:6],
weight = rep((1:3), each =2))
nodes <- cbind.data.frame(id = LETTERS[1:6],
feature = rep((1:3), each =2))
net <- graph_from_data_frame(d = links, vertices = nodes, directed = T)
V(net)$color <- V(net)$feature
plot(net, vertex.size=30, edge.arrow.size = 0)
The resulting figure looks like below:
What I want is to arrange the same colored node together, as shown in the following figure. The same colored nodes are next to each other.
I have found a very simple way to do it. Just need to use as_star layout
LO <- layout_(net, as_star())
plot(net, vertex.size = 30, edge.arrow.size = 0, layout = LO)

Setting subgraph/cluster attributes in Rgraphviz

I want to plot a graph via Rgraphviz but I can't handle the design attributes of the clusters that I set.
There are similar questions already on SO and elsewhere but none has a real minimal working example and none of them is answered. So I want to try to ask a complete question to receive a complete answer. As an introduction to the package, I read the paper "How To Plot A Graph Using Rgraphviz" by Gentry, Gentleman, and Huber.
My example network:
library(Rgraphviz)
set.seed(123)
V <- letters[1:6]
M <- 1:4
g1 <- randomGraph(V, M, 0.2)
If I want to plot it, I can easily give it some attributes via a list:
attributes <- list(node = list(shape = "rectangle", fixedsize = FALSE),
graph = list(layout = "dot", bgcolor = "transparent"))
plot(g1, attrs = attributes )
Plotting it via plot(g1) gives the following result:
Now I want to define two clusters/subgraphs. This can be done this way:
sg1= subGraph(c("a", "e", "f"), g1)
sg2= subGraph(c("b", "c", "d"), g1)
subGList <- vector(mode = "list", length = 2)
subGList[[1]] <- list(graph = sg1, cluster = TRUE)
subGList[[2]] <- list(graph = sg2, cluster = TRUE)
Plotting the graph again now including a subGlist argument:
plot(g1, attrs = attributes , subGList = subGList)
So, obviously, there has been a change in the setting and even though it would be convenient having the clusters a little bit more separated, the result is ok.
Now if I want to define cluster-specific styles or try to have them framed, I start having problems. According to page 4 of the mentioned introductory paper one can simply add an element called attrs to the sublists of subGlist.
To my understanding, it should work this way:
subGList[[1]] <- list(graph = sg1,
cluster = TRUE,
attrs = c(fontcolor = "red"))
plot(g1, attrs = attrs, subGList = subGList)
Unfortunately, it doesn't. As mentioned, I would like to frame my clusters (similar to this SO post) but as I can't even handle the fontcolors of the clusters, I think I make a somehow more fundamental mistake.
My complete code:
library(Rgraphviz)
set.seed(123)
V <- letters[1:6]
M <- 1:4
g1 <- randomGraph(V, M, 0.2)
attributes <- list(node = list(shape = "rectangle", fixedsize = FALSE),
graph = list(layout = "dot", bgcolor = "transparent"))
#plot(g1, attrs = attributes )
sg1= subGraph(c("a", "e", "f"), g1)
sg2= subGraph(c("b", "c", "d"), g1)
subGList <- vector(mode = "list", length = 2)
subGList[[1]] <- list(graph = sg1, cluster = TRUE)
subGList[[2]] <- list(graph = sg2, cluster = TRUE)
#plot(g1, attrs = attributes , subGList = subGList)
subGList[[1]] <- list(graph = sg1,
cluster = TRUE,
attrs = c(fontcolor = "red"))
plot(g1, attrs = attrs, subGList = subGList)
I hope someone can help! Thank you

plotly Sankey diagram: Can I make 4 or more links between two nodes?

I created a Sankey diagram using the plotly package.
Please look at below example. I tried to make five streams, 1_6_7, 2_6_7, and so on. But two of five links between 6 and 7 disappeared. As far as I see, plotly allows to make only three or less links between two nodes.
Can I remove this restrictions ? Any help would be greatly appreciated.
Here is an example code and the outputs:
d <- expand.grid(1:5, 6, 7)
node_label <- 1:max(d)
node_colour <- scales::alpha(RColorBrewer::brewer.pal(7, "Set2"), 0.8)
link_source_nodeind <- c(d[,1], d[,2]) - 1
link_target_nodeind <- c(d[,2], d[,3]) - 1
link_value <- rep(100, nrow(d) * 2)
link_label <- rep(paste(d[,1], d[,2], d[,3], sep = "_"), 2)
link_colour <- rep(scales::alpha(RColorBrewer::brewer.pal(5, "Set2"), 0.2), 2)
p <- plotly::plot_ly(type = "sankey",
domain = c(x = c(0,1), y = c(0,1)),
orientation = "h",
node = list(label = node_label,
color = node_colour),
link = list(source = link_source_nodeind,
target = link_target_nodeind,
value = link_value,
label = link_label,
color = link_colour))
p

Show edge attributes as label with igraph

I am using igraph in R for network analysis. I want to display an edge attribute on each line in the plot. An example is below
df <- data.frame(a = c(0,1,2,3,4),b = c(3,4,5,6,7))
nod <- data.frame(node = c(0:7),wt = c(1:8))
pg <- graph_from_data_frame(d = df, vertices = nod,directed = F)
plot(pg)
I want the value of the "wt" feature to show up between each node on the line, or preferably, in a little gap where the line breaks.
Is it possible to make this happen?
Use the parameter edge.label to assign labels of the edges, I used - probably wrong - nod$wt. Of course, you could assign other labels.
You could use the following code:
# load the package
library(igraph)
# your code
df <- data.frame(a = c(0,1,2,3,4),b = c(3,4,5,6,7))
nod <- data.frame(node = c(0:7),wt = c(1:8))
pg <- graph_from_data_frame(d = df, vertices = nod,directed = F)
# plot function with edge.label added
plot(pg, edge.label = nod$wt)
Please, let me know whether this is what you want.

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