Description
Implementation provided for the alpha parameters estimation as described in the paper of Blei, Ng and Jordan (http://www.cs.princeton.edu/~blei/papers/BleiNgJordan2003.pdf).
Remark: there is a mistake in the last formula in A.4.2 (the signs are wrong). The correct version is described here: http://www.cs.cmu.edu/~jch1/research/dirichlet/dirichlet.pdf (page 6).