Extract ancestral state estimates from a fitted coevolutionary model

Extracts posterior estimates of trait values at internal nodes of the phylogenetic tree from a fitted coevfit object. By default, estimates are returned on the latent (eta) scale; use scale = "response" to apply the inverse link for each variable's response distribution. The latent eta parameters in the model correspond directly to nodes in the phylogeny, making ancestral state reconstruction a natural byproduct of model fitting.

Usage

coev_ancestral_states(
  object,
  variables = NULL,
  nodes = "internal",
  tree_id = NULL,
  scale = "latent",
  summary = TRUE,
  prob = 0.95
)

Arguments

object

An object of class coevfit

variables

(optional) A character vector of variable names to include. If NULL (default), all variables from the fitted model are included.

nodes

Which nodes to include. Either "internal" (default) for internal nodes only, "all" for both tips and internal nodes, or an integer vector of specific node IDs (using ape's node numbering: tips = 1:N_tips, internal = (N_tips+1):total).

tree_id

(optional) An integer indicating which tree to use when the model was fit with a multiPhylo object. If NULL (default), uses tree 1. (Integration over trees with topological uncertainty is not yet implemented.)

scale

Character string, either "latent" (default) to return values on the latent eta scale, or "response" to apply the inverse link function for each variable's response distribution.

summary

Logical. If TRUE (default), returns a long-format data frame with posterior point estimates and credible intervals. If FALSE, returns the raw posterior draws.

prob

A single numeric value between 0 and 1 indicating the desired probability mass for the credible interval. Default is 0.95.

Value

If summary = TRUE, a long-format data frame (tibble) with columns:

node

Integer node ID in the reference tree

variable

Character variable name

category

Only present when scale = "response". For ordinal variables, the category label ("cat_1", "cat_2", ...). NA for non-ordinal variables.

estimate

Posterior median

lower

Lower bound of the credible interval

upper

Upper bound of the credible interval

The data frame has attributes ref_tree (the phylo object used), prob, and scale.

If summary = FALSE, a list with elements:

draws

A 3D array (draws x nodes x variables)

ref_tree

The reference phylo object

node_ids

Integer vector of node IDs (matching dim 2 of draws)

variable_names

Character vector of variable names

See also

coev_fit, coev_plot_trait_values

Examples

if (FALSE) { # \dontrun{
# fit dynamic coevolutionary model
fit <- coev_fit(
  data = authority$data,
  variables = list(
    political_authority = "ordered_logistic",
    religious_authority = "ordered_logistic"
  ),
  id = "language",
  tree = authority$phylogeny,
  chains = 4,
  parallel_chains = 4,
  seed = 1
)

# extract ancestral states (latent scale, internal nodes, summary)
asr <- coev_ancestral_states(fit)

# extract all nodes including tips
asr_all <- coev_ancestral_states(fit, nodes = "all")

# extract on response scale
asr_resp <- coev_ancestral_states(fit, scale = "response")

# get raw posterior draws
asr_draws <- coev_ancestral_states(fit, summary = FALSE)
} # }