graph: graph2SparseM – R documentation

Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!

graph2SparseM

Coercion methods between graphs and sparse matrices

Description

These functions provide coercions between objects that inherit from the graph class to sparse matrices from the SparseM package.

Usage

graph2SparseM(g, useweights=FALSE)
sparseM2Graph(sM, nodeNames, edgemode=c("directed", "undirected"))

Arguments

`g`	An instance of the `graph` class.
`useweights`	A logical value indicating whether to use the edge weights in the graph as values in the sparse matrix.
`sM`	A sparse matrix.
`nodeNames`	A `character` vector of the node names.
`edgemode`	Specifies whether the graph to be created should have directed (default) or undirected edges. If undirected, the input matrix `sM` must be symmetric.

Details

A very simple coercion from one representation to another.

Currently it is presumed that the matrix is square. For other graph formats, such as bipartite graphs, some improvements will be needed; patches are welcome.

Value

graph2SparseM takes as input an instance of a subclass of the graph class and returns a sparse matrix.

sparseM2Graph takes a sparse matrix as input and returns an instance of the graphNEL class. By default, the graphNEL returned will have directed edges.

Author(s)

R. Gentleman

Examples

set.seed(123)
  g1 <- randomGraph(letters[1:10], 1:4, p=.3)
  s1 <- graph2SparseM(g1, useweights=TRUE)
  g2 <- sparseM2Graph(s1, letters[1:10], edgemode="undirected")
  ## consistency check
  stopifnot(all.equal(g1, g2))

graph

graph: A package to handle graph data structures

v1.68.0

Artistic-2.0

Authors

R. Gentleman, Elizabeth Whalen, W. Huber, S. Falcon

Initial release