Strange Loop

Scala DSLs and Probabilistic Programming

Stan is a probabilistic programming language for statistical modeling, data analysis, and prediction with interfaces in R, Python, and other languages. By implementing a statistical model in Stan, one can perform Bayesian inference using Markov-Chain Monte-Carlo (MCMC) as well as optimization and variational inference.

ScalaStan is a fundamentally new kind of interface to Stan. Not only does ScalaStan allow one to interface with Stan from Scala, but, unlike the other Stan interfaces, ScalaStan also supports the type-safe programmatic manipulation and generation of Stan programs via an embedded domain-specific language (DSL). Thus, ScalaStan allows one to fully specify a Stan program in Scala, marshal data to and from the program in a type-safe way, and cache Stan models for fast iteration.

In this talk, we show how the Scala type system allows us to enforce type-safety in the Stan model and prevents us from generating invalid Stan code. Next, we show how the ScalaStan DSL can be used to generate higher-level Stan models. Finally, we dive into the details of several specific techniques ScalaStan employs to enforce type safety and prevent invalid code in an embedded DSL.

Joe Wingbermuehle

CiBO Technologies

Joe is a Senior Engineer at CiBO Technologies where he uses Scala to help build sophisticated models of millions of farms. Joe has a passion for programming languages and computer architecture. As part of his PhD dissertation, Joe created an embedded DSL in Scala for generating FPGA code. Previously, Joe created highly efficient low-level code you might have used if you ever played a game on your highschool TI-83 calculator, used a micro-Linux window manager, or made some high-frequency trades.