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Chris Maddison

9 accepted papers

2022

Augment with Care: Contrastive Learning for Combinatorial Problems

ICML 2022spotlight

Supervised learning can improve the design of state-of-the-art solvers for combinatorial problems, but labelling large numbers of combinatorial instances is often impractical due to exponential worst-case complexity. Inspired by the recent success of contrastive pre-training for images, we conduct a…

2022

Bayesian Nonparametrics for Offline Skill Discovery

ICML 2022spotlight

Skills or low-level policies in reinforcement learning are temporally extended actions that can speed up learning and enable complex behaviours. Recent work in offline reinforcement learning and imitation learning has proposed several techniques for skill discovery from a set of expert trajectories.…

2022

Learning to Cut by Looking Ahead: Cutting Plane Selection via Imitation Learning

ICML 2022spotlight

Cutting planes are essential for solving mixed-integer linear problems (MILPs), because they facilitate bound improvements on the optimal solution value. For selecting cuts, modern solvers rely on manually designed heuristics that are tuned to gauge the potential effectiveness of cuts. We show that…

2021

Improving Lossless Compression Rates via Monte Carlo Bits-Back Coding

ICML 2021oral

Latent variable models have been successfully applied in lossless compression with the bits-back coding algorithm. However, bits-back suffers from an increase in the bitrate equal to the KL divergence between the approximate posterior and the true posterior. In this paper, we show how to remove this…

2021

Learning Branching Heuristics for Propositional Model Counting

AAAI 2021technical

Propositional model counting, or #SAT, is the problem of computing the number of satisfying assignments of a Boolean formula. Many problems from different application areas, including many discrete probabilistic inference problems, can be translated into model counting problems to be solved by #SAT…

Cited by 17SourcePDFScholar
2021

Oops I Took A Gradient: Scalable Sampling for Discrete Distributions

ICML 2021oral

We propose a general and scalable approximate sampling strategy for probabilistic models with discrete variables. Our approach uses gradients of the likelihood function with respect to its discrete inputs to propose updates in a Metropolis-Hastings sampler. We show empirically that this approach out…

2018

Tighter Variational Bounds are Not Necessarily Better

ICML 2018oral

We provide theoretical and empirical evidence that using tighter evidence lower bounds (ELBOs) can be detrimental to the process of learning an inference network by reducing the signal-to-noise ratio of the gradient estimator. Our results call into question common implicit assumptions that tighter E…

Cited by 246SourcePDFScholar