Hi all,

I'm trying to implement David Blei's Correlated Topic Model (http://www.cs.princeton.edu/~blei/papers/BleiLafferty2007.pdf), which is basically LDA but with the per-document topic distribution drawn from a Logistic Normal Distribution rather than a Dirichlet.
More specifically, the variable is drawn from a multivariate Gaussian, put through an exponential function and then normalised so that the values sum to one.

Is there an easy way to define such a variable/distribution in Infer.NET? I went as far as defining my own Factor class but then am unsure as to how I should go about implementing its corresponding Operator class :(

Any help is greatly appreciated.

Thanks and regards,

Josiah