On the True Distribution Approximation of Minimum Bayes-Risk Decoding

Fuente: arXiv
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Main Authors: Ohashi, Atsumoto, Honda, Ukyo, Morimura, Tetsuro, Jinnai, Yuu
Format: Preprint
Published: 2024
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author Ohashi, Atsumoto
Honda, Ukyo
Morimura, Tetsuro
Jinnai, Yuu
author_facet Ohashi, Atsumoto
Honda, Ukyo
Morimura, Tetsuro
Jinnai, Yuu
contents Minimum Bayes-risk (MBR) decoding has recently gained renewed attention in text generation. MBR decoding considers texts sampled from a model as pseudo-references and selects the text with the highest similarity to the others. Therefore, sampling is one of the key elements of MBR decoding, and previous studies reported that the performance varies by sampling methods. From a theoretical standpoint, this performance variation is likely tied to how closely the samples approximate the true distribution of references. However, this approximation has not been the subject of in-depth study. In this study, we propose using anomaly detection to measure the degree of approximation. We first closely examine the performance variation and then show that previous hypotheses about samples do not correlate well with the variation, but our introduced anomaly scores do. The results are the first to empirically support the link between the performance and the core assumption of MBR decoding.
format Preprint
id arxiv_https___arxiv_org_abs_2404_00752
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the True Distribution Approximation of Minimum Bayes-Risk Decoding
Ohashi, Atsumoto
Honda, Ukyo
Morimura, Tetsuro
Jinnai, Yuu
Computation and Language
Artificial Intelligence
Minimum Bayes-risk (MBR) decoding has recently gained renewed attention in text generation. MBR decoding considers texts sampled from a model as pseudo-references and selects the text with the highest similarity to the others. Therefore, sampling is one of the key elements of MBR decoding, and previous studies reported that the performance varies by sampling methods. From a theoretical standpoint, this performance variation is likely tied to how closely the samples approximate the true distribution of references. However, this approximation has not been the subject of in-depth study. In this study, we propose using anomaly detection to measure the degree of approximation. We first closely examine the performance variation and then show that previous hypotheses about samples do not correlate well with the variation, but our introduced anomaly scores do. The results are the first to empirically support the link between the performance and the core assumption of MBR decoding.
title On the True Distribution Approximation of Minimum Bayes-Risk Decoding
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2404.00752