These functions offer tools for transforming migraph-consistent objects (matrices, igraph, tidygraph, or network objects). Transforming means that the returned object may have different dimensions than the original object.

to_mode1(object, similarity = c("count", "jaccard", "rand", "pearson", "yule"))

to_mode2(object, similarity = c("count", "jaccard", "rand", "pearson", "yule"))

to_giant(object)

to_subgraph(object, ...)

to_ties(object)

to_blocks(object, membership, FUN = mean)

to_matching(object, mark = "type")

to_anti(object)

Arguments

object

An object of a migraph-consistent class:

  • matrix (adjacency or incidence) from {base} R

  • edgelist, a data frame from {base} R or tibble from {tibble}

  • igraph, from the {igraph} package

  • network, from the {network} package

  • tbl_graph, from the {tidygraph} package

similarity

Method for establishing ties, currently "count" (default), "jaccard", or "rand". "count" calculates the number of coinciding ties, and can be interpreted as indicating the degree of opportunities between nodes. "jaccard" uses this count as the numerator in a proportion, where the denominator consists of any cell where either node has a tie. It can be interpreted as opportunity weighted by participation. "rand", or the Simple Matching Coefficient, is a proportion where the numerator consists of the count of cells where both nodes are present or both are absent, over all possible cells. It can be interpreted as the (weighted) degree of behavioral mirroring between two nodes. "pearson" (Pearson's coefficient) and "yule" (Yule's Q) produce correlations for valued and binary data, respectively. Note that Yule's Q has a straightforward interpretation related to the odds ratio.

...

Arguments passed on to dplyr::filter

membership

A vector of partition memberships.

FUN

A function for summarising block content. By default mean. Other recommended options include median, sum, min or max.

mark

A logical vector marking two types or modes. By default "type".

Details

Since some modifications are easier to implement for some objects than others, here are the currently implemented modifications:

to_edgelistsmatricesigraphtidygraphnetwork
mode1XXXXX
mode2XXXXX
giantXXXXX
subgraphXXXXX
tiesXXXXX
blocksXXXXX
matchingXXXXX

Functions

  • to_mode1(): Results in a weighted one-mode object that retains the row nodes from a two-mode object, and weights the ties between them on the basis of their joint ties to nodes in the second mode (columns)

  • to_mode2(): Results in a weighted one-mode object that retains the column nodes from a two-mode object, and weights the ties between them on the basis of their joint ties to nodes in the first mode (rows).

  • to_giant(): Returns an object that includes only the main component without any smaller components or isolates

  • to_subgraph(): Returns a network subgraph filtered on the basis of some node-related logical statement.

  • to_ties(): Returns a matrix (named if possible) where the edges are the nodes

  • to_blocks(): Returns a reduced graph from a given partition membership vector. Reduced graphs provide summary representations of network structures by collapsing groups of connected nodes into single nodes while preserving the topology of the original structures.

  • to_matching(): Returns a network with only matching ties

  • to_anti(): Returns the complement of a network where only ties not present in the original network are included in the new network.

to_matching

to_matching() uses {igraph}'s max_bipartite_match() to return a network in which each node is only tied to one of its previous ties. The number of these ties left is its cardinality, and the algorithm seeks to maximise this such that, where possible, each node will be associated with just one node in the other mode or some other mark. The algorithm used is the push-relabel algorithm with greedy initialization and a global relabelling after every \(\frac{n}{2}\) steps, where \(n\) is the number of nodes in the network.

References

Goldberg, A V; Tarjan, R E (1986). "A new approach to the maximum flow problem". Proceedings of the eighteenth annual ACM symposium on Theory of computing – STOC '86. p. 136. doi:10.1145/12130.12144

See also

Other manipulations: add, as(), grab, reformat, split()

Examples

autographr(ison_southern_women) /
(autographr(to_mode1(ison_southern_women)) |
autographr(to_mode2(ison_southern_women)))

autographr(ison_adolescents) +  
autographr(to_ties(ison_adolescents))

(adolblock <- to_blocks(ison_adolescents, 
  node_regular_equivalence(ison_adolescents, k = 3)))
#> # A tbl_graph: 3 nodes and 4 edges
#> #
#> # An undirected multigraph with 1 component
#> #
#> # Node Data: 3 × 1 (active)
#>   name   
#>   <chr>  
#> 1 Block 1
#> 2 Block 2
#> 3 Block 3
#> #
#> # Edge Data: 4 × 3
#>    from    to weight
#>   <int> <int>  <dbl>
#> 1     1     1  0.167
#> 2     1     2  0.5  
#> 3     1     3  0.5  
#> # … with 1 more row
autographr(adolblock)

autographr(to_matching(ison_southern_women), "hierarchy")

autographr(to_anti(ison_southern_women), "hierarchy")