6. The non-transitory storage medium as set forth in claim 2 , wherein the performing LDA comprises: performing LDA with an IBP compound Dirichlet prior probability distribution configured such that the inferred topic model is a clean topic model in which each topic is defined as a distribution over a sub-set of the set of vocabulary words selected by the IBP compound Dirichlet prior probability distribution.
6. The non-transitory storage medium as set forth in claim 2 , wherein the performing LDA comprises: performing LDA with an IBP compound Dirichlet prior probability distribution configured such that the inferred topic model is a clean topic model in which each topic is defined as a distribution over a sub-set of the set of vocabulary words selected by the IBP compound Dirichlet prior probability distribution. 7. The non-transitory storage medium as set forth in claim 6 , wherein the method further comprises: generating an input bag-of-words representation comprising a distribution over the set of vocabulary words for an input document which is not part of the training corpus; and classifying the input document respective to the topics of the set of topics using the clean topic model.