How do I check my check?

[agoldst]

In v0.2.2, I try to implement (the most basic version of) the posterior predictive checking for topic models described in Mimno and Blei, 2011. But verifying that the checking actually does what it ought to is...challenging for me. I'm opening this issue as a way for anyone who's interested (anyone?) to make suggestions or, better yet, to demonstrate that the mi_check and imi_check functions I've added either do or do not work correctly. These and associated functions have fairly detailed documentation in the package. The associated source is in R/mi.R, R/rmultinom_sparse.R, src/entropy.cpp, and src/multinom.cpp.