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Markov centrality (White and Smyth 2003) is the inverse of the mean first passage time of a random walk into a node: $$M(j) = \left(\frac{1}{n} \sum_{i} m_{ij}\right)^{-1},$$ where \(m_{ij}\) is the expected number of steps from \(i\) to the first visit of \(j\) and \(m_{jj} = 0\).

Usage

centrality_markov(x, ...)

Arguments

x

Network input accepted by centrality.

...

Further arguments to centrality.

Value

A named numeric vector with one score per node, in input node order.

Details

The walk moves from a node to each of its out-neighbors with equal probability, so edge weights are ignored. A disconnected network, or a directed network with a node that has no outgoing edge, gives NA for every node with a cograph_undefined_measure warning. On a directed network that is not strongly connected, a node that some other node cannot reach has an infinite mean passage time, and its score is NA with the same warning. On connected undirected and strongly connected directed networks the values equal centiserve::markovcent().

References

White, S., & Smyth, P. (2003). Algorithms for estimating relative importance in networks. In Proceedings of the Ninth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (pp. 266-275). doi:10.1145/956750.956782 .

Examples

centrality_markov(regulation_net)
#>    Explore       Plan    Monitor      Adapt    Reflect    Discuss Synthesize 
#> 0.19359291 0.06433656 0.24757007 0.20391000 0.15165989 0.07197797 0.05356390 
#>   Evaluate     Create      Share 
#> 0.04778456 0.14198438 0.15182543