TRIMS: Trajectory-Ranked Instruction Masked Supervision for Diffusion Language Models

Fuente: arXiv
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Main Authors: Chen, Lingjie, Qiu, Ruizhong, Fan, Yuyu, Zhao, Yanjun, Tong, Hanghang
Format: Preprint
Published: 2026
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author Chen, Lingjie
Qiu, Ruizhong
Fan, Yuyu
Zhao, Yanjun
Tong, Hanghang
author_facet Chen, Lingjie
Qiu, Ruizhong
Fan, Yuyu
Zhao, Yanjun
Tong, Hanghang
contents Diffusion language models (DLMs) offer a promising path toward low-latency generation through parallel decoding, but their practical efficiency depends heavily on the decoding trajectory. In practice, this advantage often fails to fully materialize because standard training does not provide explicit supervision over token reveal order, creating a train-inference mismatch that leads to suboptimal decoding behavior. We propose Trajectory-Ranked Instruction Masked Supervision (TRIMS), a simple trajectory-guided supervised fine-tuning framework that injects trajectory supervision into standard Masked Diffusion Language Model (MDLM) training with minimal overhead. Instead of relying on costly DLM-based distillation, TRIMS uses lightweight signals from an autoregressive teacher to guide a trajectory-aware masking strategy, encouraging the model to learn more effective decoding orders. Experiments on LLaDA and Dream across math and coding benchmarks show that TRIMS significantly improves the accuracy-parallelism trade-off over both standard MDLM training and train-free acceleration baselines, while achieving competitive performance with prior distillation-based approaches at substantially lower training cost. Further analysis shows that TRIMS leads to better decoding trajectories, validating the effectiveness of trajectory-guided supervision for DLMs.
format Preprint
id arxiv_https___arxiv_org_abs_2604_00666
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle TRIMS: Trajectory-Ranked Instruction Masked Supervision for Diffusion Language Models
Chen, Lingjie
Qiu, Ruizhong
Fan, Yuyu
Zhao, Yanjun
Tong, Hanghang
Computation and Language
Diffusion language models (DLMs) offer a promising path toward low-latency generation through parallel decoding, but their practical efficiency depends heavily on the decoding trajectory. In practice, this advantage often fails to fully materialize because standard training does not provide explicit supervision over token reveal order, creating a train-inference mismatch that leads to suboptimal decoding behavior. We propose Trajectory-Ranked Instruction Masked Supervision (TRIMS), a simple trajectory-guided supervised fine-tuning framework that injects trajectory supervision into standard Masked Diffusion Language Model (MDLM) training with minimal overhead. Instead of relying on costly DLM-based distillation, TRIMS uses lightweight signals from an autoregressive teacher to guide a trajectory-aware masking strategy, encouraging the model to learn more effective decoding orders. Experiments on LLaDA and Dream across math and coding benchmarks show that TRIMS significantly improves the accuracy-parallelism trade-off over both standard MDLM training and train-free acceleration baselines, while achieving competitive performance with prior distillation-based approaches at substantially lower training cost. Further analysis shows that TRIMS leads to better decoding trajectories, validating the effectiveness of trajectory-guided supervision for DLMs.
title TRIMS: Trajectory-Ranked Instruction Masked Supervision for Diffusion Language Models
topic Computation and Language
url https://arxiv.org/abs/2604.00666