Logit-KL Flow Matching: Non-Autoregressive Text Generation via Sampling-Hybrid Inference

Fuente: arXiv
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Main Authors: Sevriugov, Egor, Dragunov, Nikita, Razzhigaev, Anton, Kuznetsov, Andrey, Oseledets, Ivan
Format: Preprint
Published: 2024
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author Sevriugov, Egor
Dragunov, Nikita
Razzhigaev, Anton
Kuznetsov, Andrey
Oseledets, Ivan
author_facet Sevriugov, Egor
Dragunov, Nikita
Razzhigaev, Anton
Kuznetsov, Andrey
Oseledets, Ivan
contents Non-autoregressive (NAR) language models offer notable efficiency in text generation by circumventing the sequential bottleneck of autoregressive decoding. However, accurately modeling dependencies in discrete sequences remains challenging in this paradigm. In this work, we advance the field of NAR generation by applying conditional flow matching (CFM) methods grounded in geometrically principled interpolation, specifically leveraging Kullback-Leibler (KL) divergence geodesics, which correspond to linear interpolation in logit space. We rigorously establish that maximizing conditional likelihood in this setting precisely recovers the flow matching velocity field, supplying the theoretical justification for this approach in sequence modeling. To address practical performance gaps of basic inference, we propose a novel empirical sampling strategy that iteratively denoises and re-noises, along with a hybrid scheme that integrates our sampling method with basic procedure. Across unconditional and conditional text and code infilling, the approach improves perplexity and downstream metrics over prior NAR baselines under matched settings.
format Preprint
id arxiv_https___arxiv_org_abs_2411_16821
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Logit-KL Flow Matching: Non-Autoregressive Text Generation via Sampling-Hybrid Inference
Sevriugov, Egor
Dragunov, Nikita
Razzhigaev, Anton
Kuznetsov, Andrey
Oseledets, Ivan
Computation and Language
Machine Learning
Non-autoregressive (NAR) language models offer notable efficiency in text generation by circumventing the sequential bottleneck of autoregressive decoding. However, accurately modeling dependencies in discrete sequences remains challenging in this paradigm. In this work, we advance the field of NAR generation by applying conditional flow matching (CFM) methods grounded in geometrically principled interpolation, specifically leveraging Kullback-Leibler (KL) divergence geodesics, which correspond to linear interpolation in logit space. We rigorously establish that maximizing conditional likelihood in this setting precisely recovers the flow matching velocity field, supplying the theoretical justification for this approach in sequence modeling. To address practical performance gaps of basic inference, we propose a novel empirical sampling strategy that iteratively denoises and re-noises, along with a hybrid scheme that integrates our sampling method with basic procedure. Across unconditional and conditional text and code infilling, the approach improves perplexity and downstream metrics over prior NAR baselines under matched settings.
title Logit-KL Flow Matching: Non-Autoregressive Text Generation via Sampling-Hybrid Inference
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2411.16821