DiffPDE: Masked Diffusion Language Models as PDE Solver

Wenxuan Guo, Yuyang Hong, Lubin Fan, Zhaojin Fu, Lin Chen, Kun Ding, Shiming Xiang


Abstract
Existing approaches for synthesizing Partial Differential Equation (PDE) solvers predominantly rely on autoregressive models, yet their global left-to-right decoding incurs substantial redundancy when addressing inherently localized bugs. In this work, we challenge this inefficient paradigm and propose DiffPDE, a framework leveraging discrete diffusion language models for targeted code repair. By introducing a localized re-masking and infilling strategy, DiffPDE regenerates only erroneous regions while preserving correct context, naturally aligning generation with the sparse nature of PDE errors. Furthermore, to handle coupled bugs requiring sequential interventions, we present Iterative Debugging GRPO (ID-GRPO), a reinforcement learning scheme that enables multi-round debugging within single trajectories via intermediate rewards. Experiments on PDEBench show that DiffPDE achieves competitive accuracy, outperforms same-scale AR models, and significantly accelerates repair.
Anthology ID:
2026.findings-emnlp.57
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
1169–1186
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.57/
DOI:
Bibkey:
Cite (ACL):
Wenxuan Guo, Yuyang Hong, Lubin Fan, Zhaojin Fu, Lin Chen, Kun Ding, and Shiming Xiang. 2026. DiffPDE: Masked Diffusion Language Models as PDE Solver. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 1169–1186, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
DiffPDE: Masked Diffusion Language Models as PDE Solver (Guo et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.57.pdf