exNetwork: Sample network structure

In intergraph: Coercion Routines for Network Data Objects

Sample network structure

Description

An examples of networks together with network, edge and vertex attributes used primarly for testing. The same networks are stored in objects of class network and igraph.

Format

exNetwork,exNetwork2

is of class network

exIgraph,exIgraph2

is of class igraph

Objects exNetwork and exIgraph store directed version of the network. Objects exNetwork2 and exIgraph2 store the undirected version: all direction information from the edges is removed.

The network consists of 15 vertices and 11 edges.

• Vertex 1 is an isolate.

• Vertices 2-6 constitute a star with vertex 2 as a center.

• Vertices 7-8 and 9-10 make two dyads

• Vertcies 11, 12, 13,14 and 15 make a stem-and-leaf network.

Details

Vertices and edges has attribute label. For vertices these are simply letters from "a" to "o". For edges these are two-letter sequences corresponding to the neightboring vertices, i.e. the label for the edges linking nodes "b" and "c" will be "bc". The order is irrelevant.

In the exNetwork object the label attribute is also copied to the vertex.names attribute to facilitate plotting.

The exIgraph object has additional graph attribute layout so that by default Fruchterman-Reingold placement is used for plotting.

Examples

if(require(network, quietly=TRUE) ) print(exNetwork)
if( require(igraph, quietly=TRUE) ) print(exIgraph)


# showing-off 'network' versions
if(require(network, quietly=TRUE))
{
  op <- par(mar=c(1,1,1,1))
  layout( matrix(1:2, 1, 2, byrow=TRUE) )
  # need to change the family to device default because of faulty 'igraph'
  plot(exNetwork, main="Directed, class 'network'", displaylabels=TRUE)
  plot(exNetwork2, main="Undirected, class 'network'", displaylabels=TRUE)
  par(op)
}

# not running because of a bug in 'igraph': plot.igraph wants to set default
# font for vertex labels to 'serif', which is not supported on all devices
if(FALSE) {
# showing-off 'igraph' versions
if(require(igraph, quietly=TRUE))
{
  op <- par(mar=c(1,1,1,1))
  layout( matrix(1:2, 1, 2, byrow=TRUE) )
  plot(exIgraph, main="Directed, class 'igraph'")
  plot(exIgraph2, main="Undirected, class 'igraph'")
  par(op)
}
}

# The data was generated with the following code
if(FALSE) {
# directed igraph
g <- igraph::graph( c(2,1, 3,1, 4,1, 5,1, # star
	 6,7, 8,9, # two dyads
	 10,11, 11,12, 12,13, 13,14, 14,12), # stem-leaf
	 n=14, directed=TRUE)
# add some vertex attributes
vl <- letters[seq(1, vcount(g))]
g <- igraph::set.vertex.attribute(g, "label", value=vl)
# add some edge attributes
m <- igraph::get.edgelist(g)
l <- matrix(vl[m+1], ncol=2)
el <- apply(l, 1, paste, collapse="")
g <- igraph::set.edge.attribute(g, "label", value=el)
g <- igraph::set.graph.attribute(g, "layout", igraph::layout.fruchterman.reingold)
rm(vl, l, m, el)
exIgraph <- g

# undirected igraph
exIgraph2 <- igraph::as.undirected(exIgraph)
exIgraph2 <- igraph::set.edge.attribute(exIgraph2, "label", 
	value=igraph::get.edge.attribute(exIgraph, "label"))


# copy as a 'network' object through adjacency matrix
m <- igraph::get.adjacency(exIgraph)
g <- network::network(m, vertex.attr=list(label=vattr(exIgraph, "label")),
    vertex.attrnames="label", directed=TRUE)
network::set.vertex.attribute(g, "vertex.names", value=vattr(exIgraph, "label"))
network::set.edge.attribute(g, "label", igraph::get.edge.attribute(exIgraph, "label"))
exNetwork <- network::network.copy(g)

# copy as a 'network' object through adjacency matrix
m <- igraph::get.adjacency(exIgraph2)
g <- network::network(m, vertex.attr=list(label=vattr(exIgraph2, "label")),
    vertex.attrnames="label", directed=FALSE)
network::set.vertex.attribute(g, "vertex.names", value=vattr(exIgraph2, "label"))
network::set.edge.attribute(g, "label", igraph::get.edge.attribute(exIgraph2, "label"))
exNetwork2 <- network::network.copy(g)
}

intergraph documentation built on Aug. 21, 2023, 1:06 a.m.