Has anyone worked with the programming language Church? Can anyone recommend practical applications? I just discovered it, and while it sounds like it addresses some long-standing problems in AI and machine-learning, I'm skeptical. I had never heard of it, and was surprised to find it's actually been around for a few years, having been announced in the paper Church: a language for generative models.
A:
Likely, the article was intended to be published on April Fool's Day. Here's another article dated late march of last year. http://dspace.mit.edu/handle/1721.1/44963
coderextreme
2010-04-01 04:48:39
+1
A:
I'm not sure what to say about the matter of practical applications. Does modeling cognitive abilities with generative models constitute a "practical application" in your mind? The key importance of Church (at least right now) is that it allows those of us working with probabilistic inference solutions to AI problems a simpler way to model. It's essentially a subset of Lisp. I disagree with Chris S that it is at all a toy language. While some of these inference problems can be replicated in other languages (I've built several in Matlab) they generally aren't very reusable and you really have to love working in 4 and 5 for loops deep (I hate it). Instead of tackling the problem that way, Church uses the recursive advantages of lamda calaculus and also allows for something called memoization which is really useful for generative models since your generative model is often not the same one trial after trial--though for testing you really need this. I would say that if what you're doing has anything to do with Bayesian Networks, Hierarchical Bayesian Models, probabilistic solutions to POMDPs or Dynamic Bayesian Networks then I think Church is a great help. For what it's worth, I've worked with both Noah and Josh (two of Church's authors) and no one has a better handle on probabilistic inference right now (IMHO).
Lamda calaculus has been implemented in dozens of libraries for several languages. And memoization is a design pattern that's as old as time. There's nothing new here. I'm still not clear on why they felt they needed to invent Yet Another Lisp Dialect instead of just using Common Lisp or Scheme.
Chris S
2010-04-22 13:20:23
A:
You know what does a better job of describing Church than what I said? This MIT article: http://web.mit.edu/newsoffice/2010/ai-unification.html
It's slightly more hyperbolic, but then, I'm not immune to the optimism present in this article.