perplexity() computes the perplexity score to help users to chose the
optimal values of hyper-parameters for LDA.
perplexity(x, newdata = NULL, ...)Returns a singple numeric value.
a LDA model fitted by textmodel_seededlda() or textmodel_lda().
if provided, theta and phi are estimated through fresh
Gibbs sampling.
additional arguments passed to textmodel_lda.
perplexity() predicts the distribution of words in the dfm based
on x$alpha and x$gamma and then compute the sum of disparity between their
predicted and observed frequencies. The perplexity score minimizes when the
chosen values of hyper-parameters such as k, alpha and gamma are
optimal.
divergence