a matrix with W rows, one for each term in the
vocabulary, and K columns, one for each topic, where each
column sums to one. Each column is the multinomial
distribution over terms for a given topic in an LDA topic
model.
term.frequency
an integer vector of length W
containing the frequency of each term in the vocabulary.
vocab
a character vector of length W containing
the unique terms in the corpus.
topic.proportion
a numeric vector of length K
containing the proportion of each topic in the corpus.