DecoCal: Decoding with Calibration in Diffusion Large Language Models

Fan Xu, Huixuan Zhang, Xiaojun Wan


Abstract
Diffusion Large Language Models (DLLMs) generate text via iterative masked-token denoising, supporting parallel prediction and bidirectional context modeling. Despite these advantages, decoding remains challenging: many tokens appear predictable early, yet single-step predictions are often unstable, exhibiting temporal oscillations or overconfidence, making it difficult to determine which tokens can be safely committed. To address these challenges, we propose DecoCal, a Decoding framework that explicitly performs Calibration of token-level confidence across diffusion steps and leverages the calibrated results to guide decoding decisions. Specifically, DecoCal aggregates historical predictions to maintain calibrated confidence, triggering unmasking only when a token is sufficiently stable, while a remasking mechanism allows revision of premature commitments. This calibration-based design enables early decoding of reliably converged tokens while deferring or correcting unstable ones, balancing reliability and speed. Experiments on multiple DLLMs and benchmarks show that DecoCal improves generation accuracy compared to existing strategies. Our results highlight the importance of temporal calibration in unlocking the full potential of diffusion-based language generation.
Anthology ID:
2026.acl-long.545
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
11866–11880
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.545/
DOI:
Bibkey:
Cite (ACL):
Fan Xu, Huixuan Zhang, and Xiaojun Wan. 2026. DecoCal: Decoding with Calibration in Diffusion Large Language Models. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 11866–11880, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
DecoCal: Decoding with Calibration in Diffusion Large Language Models (Xu et al., ACL 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.545.pdf
Checklist:
 2026.acl-long.545.checklist.pdf