Build a grouped node-level network (htna) from data and a clustering

Builds the full node-level network from the original data and attaches a cluster grouping, producing a single htna network in which every actor is a node and cluster membership labels the actors. This is the node-level counterpart of build_mcml: where build_mcml collapses the network to a cluster-level (macro) summary, as_htna keeps every node and every transition - including the between-cluster transitions an mcml only retains in aggregate.

Usage

as_htna(x, clusters = NULL, method = "relative", ...)

# S3 method for class 'mcml'
as_htna(x, clusters = NULL, method = "relative", data = NULL, ...)

# S3 method for class 'net_mmm'
as_htna(x, clusters = NULL, method = "relative", ...)

# Default S3 method
as_htna(x, clusters = NULL, method = "relative", ...)

Arguments

x: Data accepted by build_network (sequence data frame, edgelist, transition matrix, netobject, or tna); or an mcml object, in which case the original data must also be supplied and the mcml provides the node-cluster membership; or a fitted net_mmm object, which is materialized into one HTNA per sequence cluster using its preserved actor partition.
clusters: Cluster assignment: a named list of node-name vectors, a per-node membership vector, or a two-column data frame. When NULL and x carries node groups (or is an mcml), those are used.
method: Estimator passed to build_network. Default "relative" (row-normalized transitions).
...: Further arguments forwarded to build_network (e.g. actor, action, time for long-format data).
data: For the mcml method, the original data the mcml was built from (sequence/edgelist/etc.). Optional when the mcml was built from sequence/edgelist data: build_mcml() stashes that source (and the actor/action/time roles), so as_htna(mcml) works on its own. Required for an mcml built from a matrix/aggregate, which retains no node-level data.

Value

For data and mcml inputs, a single htna (also a netobject and cograph_network) over all nodes. Cluster labels are stored as a factor in $nodes$groups and as character values in $node_groups$group; $actor_levels records their order and is also attached to $node_groups for lossless partition round trips. For compatibility, the result also retains $nodes$cluster and the membership in the "cluster_members" attribute. A fitted net_mmm returns an htna_group, one materialized HTNA network per sequence cluster, while preserving the MMM diagnostics.

Details

Why this rebuilds from data. An mcml stores cluster-level data (the macro sequences are recoded to cluster labels, and the per-cluster data is filtered to within-cluster nodes), so it does not retain a faithful node-level transition network. The only faithful source of node-level between-cluster transitions is the original data. as_htna() therefore rebuilds from data via build_network; an mcml supplies the cluster membership and either its retained source or explicitly supplied original data supplies the transitions.

The result is a genuine netobject, so it supports inference (bootstrap_network, centrality, permutation) and plots directly as a grouped network with cograph: cograph::plot_htna(as_htna(data, clusters)).

Examples

seqs <- data.frame(
  t1 = c("A", "C", "E", "B"), t2 = c("B", "D", "F", "A"),
  t3 = c("C", "A", "E", "D"), stringsAsFactors = FALSE
)
clusters <- list(C1 = c("A", "B"), C2 = c("C", "D"), C3 = c("E", "F"))
net <- as_htna(seqs, clusters)
net$nodes$cluster
#> [1] "C1" "C1" "C2" "C2" "C3" "C3"
if (FALSE) { # \dontrun{
cograph::plot_htna(net)
} # }