R igraph manual pages

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Create graphs from an incidence matrix

Description

graph_from_incidence_matrix creates a bipartite igraph graph from an incidence matrix.

Usage

graph_from_incidence_matrix(
  incidence,
  directed = FALSE,
  mode = c("all", "out", "in", "total"),
  multiple = FALSE,
  weighted = NULL,
  add.names = NULL
)

from_incidence_matrix(...)

Arguments

`incidence`	The input incidence matrix. It can also be a sparse matrix from the `Matrix` package.
`directed`	Logical scalar, whether to create a directed graph.
`mode`	A character constant, defines the direction of the edges in directed graphs, ignored for undirected graphs. If ‘`out`’, then edges go from vertices of the first kind (corresponding to rows in the incidence matrix) to vertices of the second kind (columns in the incidence matrix). If ‘`in`’, then the opposite direction is used. If ‘`all`’ or ‘`total`’, then mutual edges are created.
`multiple`	Logical scalar, specifies how to interpret the matrix elements. See details below.
`weighted`	This argument specifies whether to create a weighted graph from the incidence matrix. If it is `NULL` then an unweighted graph is created and the `multiple` argument is used to determine the edges of the graph. If it is a character constant then for every non-zero matrix entry an edge is created and the value of the entry is added as an edge attribute named by the `weighted` argument. If it is `TRUE` then a weighted graph is created and the name of the edge attribute will be ‘`weight`’.
`add.names`	A character constant, `NA` or `NULL`. `graph_from_incidence_matrix` can add the row and column names of the incidence matrix as vertex attributes. If this argument is `NULL` (the default) and the incidence matrix has both row and column names, then these are added as the ‘`name`’ vertex attribute. If you want a different vertex attribute for this, then give the name of the attributes as a character string. If this argument is `NA`, then no vertex attributes (other than type) will be added.
`...`	Passed to `graph_from_incidence_matrix`.

Details

Bipartite graphs have a ‘type’ vertex attribute in igraph, this is boolean and FALSE for the vertices of the first kind and TRUE for vertices of the second kind.

graph_from_incidence_matrix can operate in two modes, depending on the multiple argument. If it is FALSE then a single edge is created for every non-zero element in the incidence matrix. If multiple is TRUE, then the matrix elements are rounded up to the closest non-negative integer to get the number of edges to create between a pair of vertices.

Value

A bipartite igraph graph. In other words, an igraph graph that has a vertex attribute type.

Author(s)

Gabor Csardi csardi.gabor@gmail.com

Examples


inc <- matrix(sample(0:1, 15, repl=TRUE), 3, 5)
colnames(inc) <- letters[1:5]
rownames(inc) <- LETTERS[1:3]
graph_from_incidence_matrix(inc)

[Package igraph version 1.2.7 Index]