Feb 17, 2016: Joost-Pieter Katoen: Probabilistic Programming: Fun, but Intricate

February 17, 2016Probabilistic Programming: Fun, but Intricate
Room: HB 2FJoost-Pieter Katoen

Probabilistic programs are used in different application areas, ranging from machine learning to security and quantum computing.  In this talk, I'll discuss semantic issues of probabilistic programming languages and present several nuances of termination: whereas ordinary program termination is about whether a program has an infinite run or not, the termination of probabilistic programs is much more delicate.  I'll show that almost-sure termination is "more undecidable" than ordinary termination, and I will argue that whether a program almost surely terminates in a finite expected amount of time is the most interesting notion of termination, and even "more undecidable".  Finally, I'll show how to establish the expected run-time of a program -- and thus whether this is finite or not -- using weakest precondition calculus.