Obtains predictions of topics for new documents from a fitted CTM model
# S3 method for ctm_topic_model predict(object, newdata, ...)
a fitted object of class "ctm_topic_model"
a DTM or TCM of class dgCMatrix or a numeric vector
further arguments passed to or from other methods.
a "theta" matrix with one row per document and one column per topic
Predictions for this method are performed using the "dot" method as described in the textmineR vignette "c_topic_modeling".