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Main Authors: Wang, Shudong, Wang, Xinfei, Zhang, Chenhao, Pang, Shanchen, Gui, Haiyuan, Ji, Wenhao, Liao, Xiaojian
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2511.13133
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author Wang, Shudong
Wang, Xinfei
Zhang, Chenhao
Pang, Shanchen
Gui, Haiyuan
Ji, Wenhao
Liao, Xiaojian
author_facet Wang, Shudong
Wang, Xinfei
Zhang, Chenhao
Pang, Shanchen
Gui, Haiyuan
Ji, Wenhao
Liao, Xiaojian
contents Multi-task reinforcement learning (MTRL) seeks to learn a unified policy for diverse tasks, but often suffers from gradient conflicts across tasks. Existing masking-based methods attempt to mitigate such conflicts by assigning task-specific parameter masks. However, our empirical study shows that coarse-grained binary masks have the problem of over-suppressing key conflicting parameters, hindering knowledge sharing across tasks. Moreover, different tasks exhibit varying conflict levels, yet existing methods use a one-size-fits-all fixed sparsity strategy to keep training stability and performance, which proves inadequate. These limitations hinder the model's generalization and learning efficiency. To address these issues, we propose SoCo-DT, a Soft Conflict-resolution method based by parameter importance. By leveraging Fisher information, mask values are dynamically adjusted to retain important parameters while suppressing conflicting ones. In addition, we introduce a dynamic sparsity adjustment strategy based on the Interquartile Range (IQR), which constructs task-specific thresholding schemes using the distribution of conflict and harmony scores during training. To enable adaptive sparsity evolution throughout training, we further incorporate an asymmetric cosine annealing schedule to continuously update the threshold. Experimental results on the Meta-World benchmark show that SoCo-DT outperforms the state-of-the-art method by 7.6% on MT50 and by 10.5% on the suboptimal dataset, demonstrating its effectiveness in mitigating gradient conflicts and improving overall multi-task performance.
format Preprint
id arxiv_https___arxiv_org_abs_2511_13133
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Soft Conflict-Resolution Decision Transformer for Offline Multi-Task Reinforcement Learning
Wang, Shudong
Wang, Xinfei
Zhang, Chenhao
Pang, Shanchen
Gui, Haiyuan
Ji, Wenhao
Liao, Xiaojian
Machine Learning
Artificial Intelligence
Multi-task reinforcement learning (MTRL) seeks to learn a unified policy for diverse tasks, but often suffers from gradient conflicts across tasks. Existing masking-based methods attempt to mitigate such conflicts by assigning task-specific parameter masks. However, our empirical study shows that coarse-grained binary masks have the problem of over-suppressing key conflicting parameters, hindering knowledge sharing across tasks. Moreover, different tasks exhibit varying conflict levels, yet existing methods use a one-size-fits-all fixed sparsity strategy to keep training stability and performance, which proves inadequate. These limitations hinder the model's generalization and learning efficiency. To address these issues, we propose SoCo-DT, a Soft Conflict-resolution method based by parameter importance. By leveraging Fisher information, mask values are dynamically adjusted to retain important parameters while suppressing conflicting ones. In addition, we introduce a dynamic sparsity adjustment strategy based on the Interquartile Range (IQR), which constructs task-specific thresholding schemes using the distribution of conflict and harmony scores during training. To enable adaptive sparsity evolution throughout training, we further incorporate an asymmetric cosine annealing schedule to continuously update the threshold. Experimental results on the Meta-World benchmark show that SoCo-DT outperforms the state-of-the-art method by 7.6% on MT50 and by 10.5% on the suboptimal dataset, demonstrating its effectiveness in mitigating gradient conflicts and improving overall multi-task performance.
title Soft Conflict-Resolution Decision Transformer for Offline Multi-Task Reinforcement Learning
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2511.13133