netdiffuseR (version 1.16.2)

isolated: Find and remove isolated vertices

Description

Find and remove unconnected vertices from the graph.

Usage

isolated(graph, undirected = getOption("diffnet.undirected"))
drop_isolated(graph, undirected = getOption("diffnet.undirected"))

Arguments

graph

Any class of accepted graph format (see netdiffuseR-graphs).

undirected

Logical. TRUE when the graph is undirected.

Value

• When graph is an adjacency matrix:
• isolated
  an matrix of size $n\times 1$ with 1's where a node is isolated
• drop_isolated
  a modified graph excluding isolated vertices.
• Otherwise, when graph is a list
• isolated
  an matrix of size $n\times T$ with 1's where a node is isolated
• drop_isolated
  a modified graph excluding isolated vertices.

See Also

Other data management functions: edgelist_to_adjmat

Examples

# Generating random graph
set.seed(123)
adjmat <- rgraph_er()

# Making nodes 1 and 4 isolated
adjmat[c(1,4),] <- 0
adjmat[,c(1,4)] <- 0
adjmat

# Finding isolated nodes
iso <- isolated(adjmat)
iso

# Removing isolated nodes
drop_isolated(adjmat)


# Now with a dynamic graph
graph <- rgraph_er(n=10, t=3)

# Making 1 and 5 isolated
graph <- lapply(graph, "[<-", i=c(1,5), j=1:10, value=0)
graph <- lapply(graph, "[<-", i=1:10, j=c(1,5), value=0)
graph

isolated(graph)
drop_isolated(graph)