Coercion from Matrices to Network Objects

as.network.matrix attempts to coerce its first argument to an object of class network.

# Default S3 method
as.network(x, ...)

# S3 method for class 'matrix'
as.network(
  x,
  matrix.type = NULL,
  directed = TRUE,
  hyper = FALSE,
  loops = FALSE,
  multiple = FALSE,
  bipartite = FALSE,
  ignore.eval = TRUE,
  names.eval = NULL,
  na.rm = FALSE,
  edge.check = FALSE,
  ...
)

Arguments

x

a matrix containing an adjacency structure

...

additional arguments

matrix.type

one of "adjacency", "edgelist", "incidence", or NULL

directed

logical; should edges be interpreted as directed?

hyper

logical; are hyperedges allowed?

loops

logical; should loops be allowed?

multiple

logical; are multiplex edges allowed?

bipartite

count; should the network be interpreted as bipartite? If present (i.e., non-NULL) it is the count of the number of actors in the bipartite network. In this case, the number of nodes is equal to the number of actors plus the number of events (with all actors preceding all events). The edges are then interpreted as nondirected.

ignore.eval

logical; ignore edge values?

names.eval

optionally, the name of the attribute in which edge values should be stored

na.rm

logical; ignore missing entries when constructing the network?

edge.check

logical; perform consistency checks on new edges?

Value

An object of class network

Details

Depending on matrix.type, one of three edgeset constructor methods will be employed to read the input matrix (see edgeset.constructors). If matrix.type==NULL, which.matrix.type will be used to guess the appropriate matrix type.

The coercion methods will recognize and attempt to utilize the sna extended matrix attributes where feasible. These are as follows:

• "n": taken to indicate number of vertices in the network.

• "bipartite": taken to indicate the network's bipartite attribute, where present.

• "vnames": taken to contain vertex names, where present.

These attributes are generally used with edgelists, and indeed data in sna edgelist format should be transparently converted in most cases. Where the extended matrix attributes are in conflict with the actual contents of x, results are no guaranteed (but the latter will usually override the former). For an edge list, the number of nodes in a network is determined by the number of unique nodes specified. If there are isolate nodes not in the edge list, the "n" attribute needs to be set. See example below.

References

Butts, C. T. (2008). “network: a Package for Managing Relational Data in R.” Journal of Statistical Software, 24(2). doi:10.18637/jss.v024.i02

See also

edgeset.constructors, network, which.matrix.type

Author

Carter T. Butts buttsc@uci.edu and David Hunter dhunter@stat.psu.edu

Examples

#Draw a random matrix
m<-matrix(rbinom(25,1,0.5),5)
diag(m)<-0

#Coerce to network form
g<-as.network.matrix(m,matrix.type="adjacency")

# edge list example. Only 4 nodes in the edge list.
m = matrix(c(1,2, 2,3, 3,4), byrow = TRUE, nrow=3)
attr(m, 'n') = 7
as.network(m, matrix.type='edgelist')
#>  Network attributes:
#>   vertices = 7 
#>   directed = TRUE 
#>   hyper = FALSE 
#>   loops = FALSE 
#>   multiple = FALSE 
#>   bipartite = FALSE 
#>   total edges= 3 
#>     missing edges= 0 
#>     non-missing edges= 3 
#> 
#>  Vertex attribute names: 
#>     vertex.names 
#> 
#> No edge attributes