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James Townsend

6 accepted papers

2024

Entropy Coding of Unordered Data Structures

ICLR 2024poster

We present shuffle coding, a general method for optimal compression of sequences of unordered objects using bits-back coding. Data structures that can be compressed using shuffle coding include multisets, graphs, hypergraphs, and others. We release an implementation that can easily be adapted to dif…

2023

One-Shot Compression of Large Edge-Exchangeable Graphs using Bits-Back Coding

ICML 2023poster

We present a one-shot method for compressing large labeled graphs called Random Edge Coding. When paired with a parameter-free model based on Pólya's Urn, the worst-case computational and memory complexities scale quasi-linearly and linearly with the number of observed edges, making it efficient on…

Cited by 3SourcePDFScholar
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…

2020

HiLLoC: lossless image compression with hierarchical latent variable models

ICLR 2020poster

We make the following striking observation: fully convolutional VAE models trained on 32x32 ImageNet can generalize well, not just to 64x64 but also to far larger photographs, with no changes to the model. We use this property, applying fully convolutional models to lossless compression, demonstrati…

Cited by 81SourcecodeScholar
2019

Practical lossless compression with latent variables using bits back coding

ICLR 2019poster

Deep latent variable models have seen recent success in many data domains. Lossless compression is an application of these models which, despite having the potential to be highly useful, has yet to be implemented in a practical manner. We present '`Bits Back with ANS' (BB-ANS), a scheme to perform l…