graph.incidence {igraph} | R Documentation |
graph.incidence
creates a bipartite igraph graph
from an incidence matrix.
graph.incidence(incidence, directed = FALSE, mode = c("all", "out", "in", "total"), multiple = FALSE, weighted = NULL, add.names = NULL)
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.incidence 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.
|
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.incidence
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.
A bipartite igraph graph. In other words, an igraph graph that has a
vertex attribute type
.
Gabor Csardi csardi@rmki.kfki.hu
graph.bipartite
for another way to create
bipartite graphs
inc <- matrix(sample(0:1, 15, repl=TRUE), 3, 5) colnames(inc) <- letters[1:5] rownames(inc) <- LETTERS[1:3] graph.incidence(inc)