Probabilistic topic modeling of text collections is a powerful tool for statistical text analysis. Determining the optimal number of topics remains a challenging problem in topic modeling. We propose a simple entropy regularization for topic selection in terms of
Additive Regularization of Topic Models
(ARTM), a multicriteria approach for combining regularizers. The entropy regularization gradually eliminates insignificant and linearly dependent topics. This process converges to the correct value on semi-real data. On real text collections it can be combined with sparsing, smoothing and decorrelation regularizers to produce a sequence of models with different numbers of well interpretable topics.