Affiliation network structure

Test igraph objects for affiliation network structure or impose such structure if possible.

Usage

is_an(graph)

is.an(graph)

as_an(graph, map_type = FALSE)

as.an(graph, map_type = FALSE)

Arguments

graph

An igraph object.

map_type

Logical; whether to add a type attribute for bipartite structure if graph admits one.

Value

For is_an(), a logical value; for as_an(), the input graph with a "type" attribute.

Details

An affiliation network is a bipartite graph whose nodes are classified as actors and events in such a way that all links are between actors and events. The function is_bipartite() tests an igraph object for a type attribute, which is intended to bipartition of the nodes. It does not test whether the links respect this partition. The function is_an tests this, as well as the condition that actor nodes precede event nodes in their node IDs, which simplifies some other functions. The function as_an coerces an igraph object to an affiliation network by verifying that the object is bipartite and minimally permuting the node IDs. If graph has no type attribute and map_type is FALSE, then as_an throws an error; if map_type is TRUE, then as_an calls bipartite_mapping() to add a logical type attribute that takes the value FALSE at the first node (by node ID) in each connected component and TRUE or FALSE at the remaining nodes. (If this cannot be done, an error is thrown.)

See also

Original igraph functions: is_igraph()

Other network testing and coercion: dynamic_an

Examples

graph <- make_graph(c( 1,2, 1,4, 1,6, 3,6, 5,6, 7,8, 9,8 ))
is_an(graph)
#> [1] FALSE
# as_an(graph) # throws an error
an_graph <- as_an(graph, map_type = TRUE)
#> Warning: Graph is directed; collapsing directed links.
is_an(an_graph)
#> [1] TRUE