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SUMMARY:Moritz Schauer (Chalmers University of Technology & University of 
 Gothenburg)
DTSTART:20221020T131500Z
DTEND:20221020T140000Z
DTSTAMP:20260422T155025Z
UID:gbgstats/5
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/gbgstats/5/"
 >Automatic differentiation of programs with discrete randomness</a>\nby Mo
 ritz Schauer (Chalmers University of Technology & University of Gothenburg
 ) as part of Gothenburg statistics seminar\n\nLecture held in MVL14.\n\nAb
 stract\nAutomatic differentiation (AD)\, a technique for constructing new 
 programs which compute the derivative of an original program\, has become 
 ubiquitous throughout scientific computing and deep learning due to the im
 proved performance afforded by gradient-based optimization. However\, AD s
 ystems have been restricted to the subset of programs that have a continuo
 us dependence on parameters. Programs that have discrete stochastic behavi
 ors governed by distribution parameters\, such as flipping a coin with pro
 bability p of being heads\, pose a challenge to these systems because the 
 connection between the result (heads vs tails) and the parameters (p) is f
 undamentally discrete. In this paper we develop a new reparameterization-b
 ased methodology that allows for generating programs whose expectation is 
 the derivative of the expectation of the original program. We showcase how
  this method gives an unbiased and low-variance estimator which is as auto
 mated as traditional AD mechanisms. We demonstrate unbiased forward-mode A
 D of discrete-time Markov chains\, agent-based models such as Conway's Gam
 e of Life\, and unbiased reverse-mode AD of a particle filter. Our code is
  available at https://github.com/gaurav-arya/StochasticAD.jl\n
LOCATION:https://researchseminars.org/talk/gbgstats/5/
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