graph2SparseM {graph} | R Documentation

## 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

### See Also

`graph-class`, `graphNEL-class`, and for other conversions, `aM2bpG` and `ftM2adjM`

### 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))

[Package graph version 1.65.3 Index]