R: Nodal attribute-based homophily effect for the first mode in...

b1nodematch-ergmTerm {ergm}

R Documentation

Nodal attribute-based homophily effect for the first mode in a bipartite network

Description

This term is introduced in Bomiriya et al (2014). With the default alpha and beta values, this term will simply be a homophily based two-star statistic. This term adds one statistic to the model unless diff is set to TRUE , in which case the term adds multiple network statistics to the model, one for each of (a subset of) the unique values of the attr attribute.

Usage

# binary: b1nodematch(attr, diff=FALSE, keep=NULL, alpha=1, beta=1, byb2attr=NULL,
#                     levels=NULL)

Arguments

`attr`	a vertex attribute specification (see Specifying Vertex attributes and Levels (`?nodal_attributes`) for details.)
`diff`	by default, one statistic will be added to the model. If `diff` is set to `TRUE`, one statistic will be added for each unique value of the `attr` attribute
`keep`	deprecated
`alpha`, `beta`	optional discount parameters both of which take values from `⁠[0, 1]⁠`, only one should be set at one time
`byb2attr`	specifies a second mode categorical attribute. Setting this argument will separate the orginal statistics based on the values of the set second mode attribute— i.e. for example, if `diff` is `FALSE` , then the sum of all the statistics for each level of this second-mode attribute will be equal to the original `b1nodematch` statistic where `byb2attr` set to `NULL` .
`levels`	select a subset of `attr` values to include. (See Specifying Vertex attributes and Levels (`?nodal_attributes`) for details.)

Details

If an alpha discount parameter is used, each of these statistics gives the sum of the number of common second-mode nodes raised to the power alpha for each pair of first-mode nodes with that attribute. If a beta discount parameter is used, each of these statistics gives half the sum of the number of two-paths with two first-mode nodes with that attribute as the two ends of the two path raised to the power beta for each edge in the network.

Note

This term can only be used with undirected bipartite networks.

The argument keep is retained for backwards compatibility and may be removed in a future version. When both keep and levels are passed, levels overrides keep.