QUEST: Quality-Aware Metropolis-Hastings Sampling for Machine Translation

Fuente: arXiv
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Main Authors: Faria, Gonçalo R. A., Agrawal, Sweta, Farinhas, António, Rei, Ricardo, de Souza, José G. C., Martins, André F. T.
Format: Preprint
Published: 2024
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author Faria, Gonçalo R. A.
Agrawal, Sweta
Farinhas, António
Rei, Ricardo
de Souza, José G. C.
Martins, André F. T.
author_facet Faria, Gonçalo R. A.
Agrawal, Sweta
Farinhas, António
Rei, Ricardo
de Souza, José G. C.
Martins, André F. T.
contents An important challenge in machine translation (MT) is to generate high-quality and diverse translations. Prior work has shown that the estimated likelihood from the MT model correlates poorly with translation quality. In contrast, quality evaluation metrics (such as COMET or BLEURT) exhibit high correlations with human judgments, which has motivated their use as rerankers (such as quality-aware and minimum Bayes risk decoding). However, relying on a single translation with high estimated quality increases the chances of "gaming the metric''. In this paper, we address the problem of sampling a set of high-quality and diverse translations. We provide a simple and effective way to avoid over-reliance on noisy quality estimates by using them as the energy function of a Gibbs distribution. Instead of looking for a mode in the distribution, we generate multiple samples from high-density areas through the Metropolis-Hastings algorithm, a simple Markov chain Monte Carlo approach. The results show that our proposed method leads to high-quality and diverse outputs across multiple language pairs (English$\leftrightarrow${German, Russian}) with two strong decoder-only LLMs (Alma-7b, Tower-7b).
format Preprint
id arxiv_https___arxiv_org_abs_2406_00049
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle QUEST: Quality-Aware Metropolis-Hastings Sampling for Machine Translation
Faria, Gonçalo R. A.
Agrawal, Sweta
Farinhas, António
Rei, Ricardo
de Souza, José G. C.
Martins, André F. T.
Computation and Language
Machine Learning
An important challenge in machine translation (MT) is to generate high-quality and diverse translations. Prior work has shown that the estimated likelihood from the MT model correlates poorly with translation quality. In contrast, quality evaluation metrics (such as COMET or BLEURT) exhibit high correlations with human judgments, which has motivated their use as rerankers (such as quality-aware and minimum Bayes risk decoding). However, relying on a single translation with high estimated quality increases the chances of "gaming the metric''. In this paper, we address the problem of sampling a set of high-quality and diverse translations. We provide a simple and effective way to avoid over-reliance on noisy quality estimates by using them as the energy function of a Gibbs distribution. Instead of looking for a mode in the distribution, we generate multiple samples from high-density areas through the Metropolis-Hastings algorithm, a simple Markov chain Monte Carlo approach. The results show that our proposed method leads to high-quality and diverse outputs across multiple language pairs (English$\leftrightarrow${German, Russian}) with two strong decoder-only LLMs (Alma-7b, Tower-7b).
title QUEST: Quality-Aware Metropolis-Hastings Sampling for Machine Translation
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2406.00049