Graph motifs

Graph motifs are small connected induced subgraphs with a well-defined structure. These functions search a graph for various motifs.

sample_motifs(
  graph,
  size = 3,
  cut.prob = rep(0, size),
  sample.size = NULL,
  sample = NULL
)

Arguments

graph

Graph object, the input graph.

size

The size of the motif, currently size 3 and 4 are supported in directed graphs and sizes 3-6 in undirected graphs.

cut.prob

Numeric vector giving the probabilities that the search graph is cut at a certain level. Its length should be the same as the size of the motif (the size argument). If NULL, the default, no cuts are made.

sample.size

The number of vertices to use as a starting point for finding motifs. Only used if the sample argument is NULL. The default is ceiling(vcount(graph) / 10) .

sample

If not NULL then it specifies the vertices to use as a starting point for finding motifs.

Value

A numeric scalar, an estimate for the total number of motifs in the graph.

Details

sample_motifs() estimates the total number of motifs of a given size in a graph based on a sample.

See also

isomorphism_class()

Other graph motifs: count_motifs(), dyad_census(), motifs()

Examples

g <- sample_pa(100)
motifs(g, 3)
#>  [1]  NA  NA 401  NA  93   0   0   0   0   0   0   0   0   0   0   0
count_motifs(g, 3)
#> [1] 494
sample_motifs(g, 3)
#> [1] 60