isolated function

Find and remove isolated vertices

Find and remove unconnected vertices from the graph.

isolated(
  graph,
  undirected = getOption("diffnet.undirected", FALSE),
  self = getOption("diffnet.self", FALSE)
)

drop_isolated(
  graph,
  undirected = getOption("diffnet.undirected", FALSE),
  self = getOption("diffnet.self", FALSE)
)

Arguments

• graph: Any class of accepted graph format (see netdiffuseR-graphs).
• undirected: Logical scalar. When TRUE only the lower triangle of the adjacency matrix will considered (faster).
• self: Logical scalar. When TRUE autolinks (loops, self edges) are allowed (see details).

Returns

When graph is an adjacency matrix: - isolated: an matrix of size $n*1$ 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 $n*T$ with 1's where a node is isolated

• drop_isolated: a modified graph excluding isolated vertices.

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)

See Also

Other data management functions: diffnet-class, edgelist_to_adjmat(), egonet_attrs(), survey_to_diffnet()

Author(s)

George G. Vega Yon