Convert cluster_summary to tna Objects

Converts a cluster_summary object to proper tna objects that can be used with all functions from the tna package. Creates a macro (cluster-level) tna model and per-cluster tna models (internal transitions within each cluster), returned as a flat group_tna object.

Usage

as_tna(x)

# S3 method for class 'cluster_summary'
as_tna(x)

# S3 method for class 'mcml'
as_tna(x)

# Default S3 method
as_tna(x)

Arguments

x: A cluster_summary object created by cluster_summary. The cluster_summary should typically be created with type = "tna" to ensure row-normalized transition probabilities. If created with type = "raw", the raw counts will be passed to tna::tna() which will normalize them.

Value

A group_tna object (S3 class) – a flat named list of tna objects. The first element is named "macro" and represents the cluster-level transitions. Subsequent elements are named by cluster name and represent internal transitions within each cluster.

macro: A tna object representing cluster-level transitions. Contains $weights (k x k transition matrix), $inits (initial distribution), and $labels (cluster names). Use this for analyzing how learners/entities move between high-level groups or phases.
<cluster_name>: Per-cluster tna objects, one per cluster. Each tna object represents internal transitions within that cluster. Contains $weights (n_i x n_i matrix), $inits (initial distribution), and $labels (node labels). Clusters with single nodes or zero-row nodes are excluded (tna requires positive row sums).

A group_tna object (flat list of tna objects: macro + per-cluster).

A tna object constructed from the input.

Details

This is the final step in the MCML workflow, enabling full integration with the tna package for centrality analysis, bootstrap validation, permutation tests, and visualization.

Requirements

The tna package must be installed. If not available, the function throws an error with installation instructions.

Workflow


# Full MCML workflow
net <- cograph(edges, nodes = nodes)
net$nodes$clusters <- group_assignments
cs <- cluster_summary(net, type = "tna")
tna_models <- as_tna(cs)

# Now use tna package functions
plot(tna_models$macro)
tna::centralities(tna_models$macro)
tna::bootstrap(tna_models$macro, iter = 1000)

# Analyze per-cluster patterns
plot(tna_models$ClusterA)
tna::centralities(tna_models$ClusterA)

Excluded Clusters

A per-cluster tna cannot be created when:

The cluster has only 1 node (no internal transitions possible)
Some nodes in the cluster have no outgoing edges (row sums to 0)

These clusters are silently excluded. The macro (cluster-level) model still includes all clusters.

Examples

mat <- matrix(runif(36), 6, 6); diag(mat) <- 0
rownames(mat) <- colnames(mat) <- LETTERS[1:6]
clusters <- list(G1 = c("A","B"), G2 = c("C","D"), G3 = c("E","F"))
cs <- cluster_summary(mat, clusters, type = "tna")
tna_models <- as_tna(cs)
names(tna_models)          # "macro", "G1", "G2", "G3"
#> [1] "macro" "G1"    "G2"    "G3"   
splot(tna_models$macro)    # cograph renderer avoids tna's plot deps