CoDAR: Continuous Diffusion Language Models are More Powerful Than You Think

Fuente: arXiv
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Hauptverfasser: Shen, Junzhe, Zhao, Jieru, He, Ziwei, Lin, Zhouhan
Format: Preprint
Veröffentlicht: 2026
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author Shen, Junzhe
Zhao, Jieru
He, Ziwei
Lin, Zhouhan
author_facet Shen, Junzhe
Zhao, Jieru
He, Ziwei
Lin, Zhouhan
contents We study why continuous diffusion language models (DLMs) have lagged behind discrete diffusion approaches despite their appealing continuous generative dynamics. Under a controlled token--recovery study, we identify token rounding, the final projection from denoised embeddings to tokens, as a primary bottleneck. Building on these insights, we propose CoDAR (Continuous Diffusion with Contextual AutoRegressive Decoder), a two--stage framework that keeps diffusion entirely continuous in an embedding space while learning a strong, context--conditional discretizer: an autoregressive Transformer decoder that cross--attends to the denoised embedding sequence and performs contextualized rounding to tokens. Experiments on LM1B and OpenWebText demonstrate that CoDAR substantially improves generation quality over latent diffusion and becomes competitive with strong discrete DLMs, while exposing a simple decoder--temperature knob to navigate the fluency--diversity trade off.
format Preprint
id arxiv_https___arxiv_org_abs_2603_02547
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CoDAR: Continuous Diffusion Language Models are More Powerful Than You Think
Shen, Junzhe
Zhao, Jieru
He, Ziwei
Lin, Zhouhan
Computation and Language
Artificial Intelligence
Machine Learning
We study why continuous diffusion language models (DLMs) have lagged behind discrete diffusion approaches despite their appealing continuous generative dynamics. Under a controlled token--recovery study, we identify token rounding, the final projection from denoised embeddings to tokens, as a primary bottleneck. Building on these insights, we propose CoDAR (Continuous Diffusion with Contextual AutoRegressive Decoder), a two--stage framework that keeps diffusion entirely continuous in an embedding space while learning a strong, context--conditional discretizer: an autoregressive Transformer decoder that cross--attends to the denoised embedding sequence and performs contextualized rounding to tokens. Experiments on LM1B and OpenWebText demonstrate that CoDAR substantially improves generation quality over latent diffusion and becomes competitive with strong discrete DLMs, while exposing a simple decoder--temperature knob to navigate the fluency--diversity trade off.
title CoDAR: Continuous Diffusion Language Models are More Powerful Than You Think
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2603.02547