For gt_cluster_pca
, autoplot
produces a plot of a metric of choice
('BIC', 'AIC' or 'WSS') against the number of clusters (k). This plot is
can be used to infer the best value of k, which corresponds to the smallest
value of the metric (the minimum in an 'elbow' shaped curve). In some cases,
there is not 'elbow' and the metric keeps decreasing with increasing k; in
such cases, it is customary to choose the value of k at which the decrease
in the metric reaches as plateau. For a programmatic way of choosing
k, use gt_cluster_pca_best_k()
.