R igraph manual pages

Random walk on a graph

Description

Do a random walk. From the given start vertex, take the given number of steps, choosing an edge from the actual vertex uniformly randomly. Edge directions are observed in directed graphs (see the mode argument as well). Multiple and loop edges are also observed.

Usage

random_walk(graph, start, steps, mode = c("out", "in", "all"),
  stuck = c("return", "error"))

Arguments

graph	The input graph, might be undirected or directed.
start	The start vertex.
steps	The number of steps to make.
mode	How to follow directed edges. "out" steps along the edge direction, "in" is opposite to that. "all" ignores edge directions. This argument is ignored for undirected graphs.
stuck	What to do if the random walk gets stuck. "return" returns the partial walk, "error" raises an error.

Value

A vertex sequence containing the vertices along the walk.

Examples

## Stationary distribution of a Markov chain
g <- make_ring(10, directed = TRUE) %u%
  make_star(11, center = 11) + edge(11, 1)

ec <- eigen_centrality(g, directed = TRUE)$vector
pg <- page_rank(g, damping = 0.999)$vector
w <- random_walk(g, start = 1, steps = 10000)

## These are similar, but not exactly the same
cor(table(w), ec)

## But these are (almost) the same
cor(table(w), pg)

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