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#' Get the eigen centrality for all nodes
#'
#' @description
#'
#' Get the eigen centrality values for all nodes in the graph.
#'
#' @inheritParams render_graph
#' @param weights_attr An optional name of the edge attribute to use in the
#' adjacency matrix. If `NULL` then, if it exists, the `weight` edge attribute
#' of the graph will be used. If `NA` then no edge weights will be used.
#'
#' @return A data frame with eigen centrality scores for each of the nodes.
#'
#' @examples
#' # Create a random graph using the
#' # `add_gnm_graph()` function
#' graph <-
#' create_graph(
#' directed = FALSE) %>%
#' add_gnm_graph(
#' n = 10, m = 15,
#' set_seed = 23)
#'
#' # Get the eigen centrality scores
#' # for nodes in the graph
#' graph %>% get_eigen_centrality()
#'
#' @export
get_eigen_centrality <- function(
graph,
weights_attr = NULL
) {
# Validation: Graph object is valid
check_graph_valid(graph)
# Convert the graph to an igraph object
ig_graph <- to_igraph(graph)
if (inherits(weights_attr, "character")) {
# Stop function if the edge attribute does not exist
if (!(weights_attr %in% colnames(graph$edges_df))) {
cli::cli_abort(
"The edge attribute to be used as weights does not exist in the graph.")
}
# Stop function if the edge attribute is not numeric
if (!is.numeric(graph$edges_df[, which(colnames(graph$edges_df) == weights_attr)])) {
cli::cli_abort(
"The edge attribute to be used as weights is not numeric.")
}
weights_attr <- graph$edges_df[, which(colnames(graph$edges_df) == weights_attr)]
}
# Get the eigen centrality values for each of the
# graph's nodes
eigen_centrality_values <-
igraph::eigen_centrality(
graph = ig_graph,
weights = weights_attr)
# Create df with eigen centrality values
data.frame(
id = names(eigen_centrality_values$vector) %>% as.integer(),
eigen_centrality = unname(eigen_centrality_values$vector) %>% round(4),
stringsAsFactors = FALSE)
}
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