combineNodes
A function to combine, or collapse, a specified set of nodes in a graph.
combineNodes(nodes, graph, newName, ...) ## S4 method for signature 'character,graphNEL,character' combineNodes(nodes, graph, newName, collapseFunction=sum)
nodes |
A set of nodes that are to be collapsed. |
graph |
The graph containing the nodes |
newName |
The name for the new, collapsed node. |
collapseFunction |
Function or character giving the name of a function used to collapse the edge weights after combining nodes. The default is to sum up the weights, but mean would be a useful alternative. |
... |
Additional arguments for the generic |
The nodes specified are reduced to a single new node with label given
by newName. The in and out edges of the set of nodes are all
made into in and out edges for the new node.
An new instance of a graph of the same class as graph is
returned. This new graph has the specified nodes reduced to a single
node.
R. Gentleman
V <- LETTERS[1:4]
edL1 <- vector("list", length=4)
names(edL1) <- V
for(i in 1:4)
edL1[[i]] <- list(edges=c(2,1,4,3)[i], weights=sqrt(i))
gR <- graphNEL(nodes=V, edgeL=edL1, edgemode="directed")
gR <- addNode("M", gR)
gR <- addEdge("M", "A", gR, 1)
gR <- addEdge("B", "D", gR, 1)
gX <- combineNodes(c("B","D"), gR, "X")
gR <- addNode("K", gR)
gR <- addEdge(c("K","K"), c("D", "B"), gR, c(5,3))
edgeWeights(combineNodes(c("B","D"), gR, "X"))$K
edgeWeights(combineNodes(c("B","D"), gR, "X", mean))$KPlease choose more modern alternatives, such as Google Chrome or Mozilla Firefox.