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The within-module degree z-score (Guimera and Nunes Amaral 2005) standardizes the number of ties a node has inside its own community against the other members of that community: $$z_i = \frac{\kappa_i - \bar{\kappa}_{s_i}}{\sigma_{\kappa_{s_i}}},$$ where \(\kappa_i\) counts the ties of \(i\) to its community \(s_i\). High values mark hubs within their community.

Usage

centrality_within_module_z(x, membership = NULL, mode = "all", ...)

Arguments

x

Network input accepted by centrality.

membership

Community of each node, a vector with one entry per node in input node order (default NULL).

mode

Direction for directed networks: "all" (default), "out" or "in".

...

Further arguments to centrality.

Value

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

Details

Edge weights are ignored. mode selects the ties counted, and with mode = "all" on a directed network a reciprocated tie counts twice. The standard deviation is the sample value. A community with one member, or whose members all have the same within-community degree, gives NaN. Without membership every score is NA with a warning of classes cograph_bad_membership and cograph_undefined_measure, and a membership of the wrong length raises a cograph_bad_membership error. On undirected networks the values equal brainGraph::within_module_deg_z_score().

References

Guimera, R., & Nunes Amaral, L. A. (2005). Functional cartography of complex metabolic networks. Nature, 433(7028), 895-900. doi:10.1038/nature03288 .

Examples

centrality_within_module_z(regulation_net, membership = rep(1:2, each = 5))
#>    Explore       Plan    Monitor      Adapt    Reflect    Discuss Synthesize 
#>  0.6708204 -1.5652476  0.6708204 -0.4472136  0.6708204 -0.1825742 -1.0954451 
#>   Evaluate     Create      Share 
#> -0.1825742  1.6431677 -0.1825742