Smooth Gate Functions for Soft Advantage Policy Optimization

Fuente: arXiv
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Autori principali: Denisov, Egor, Glazyrina, Svetlana, Kryzhanovskiy, Maksim, Ischenko, Roman
Natura: Preprint
Pubblicazione: 2026
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author Denisov, Egor
Glazyrina, Svetlana
Kryzhanovskiy, Maksim
Ischenko, Roman
author_facet Denisov, Egor
Glazyrina, Svetlana
Kryzhanovskiy, Maksim
Ischenko, Roman
contents Group Relative Policy Optimization (GRPO) has significantly advanced the training of large language models and enhanced their reasoning capabilities, while it remains susceptible to instability due to the use of hard clipping. Soft Adaptive Policy Optimization (SAPO) addresses this limitation by replacing clipping with a smooth sigmoid-based gate function, which leads to more stable updates. We have decided to push this theory further and investigate the impact of different gate functions on both training stability and final model performance. We formalize the key properties that admissible gates should satisfy and identify several families of such functions for empirical evaluation. This paper presents an analysis of our findings based on experiments conducted with the Qwen2.5-7B-Instruct model on mathematical reasoning tasks. These results provide practical guidance for designing smoother and more robust policy optimization objectives for large language model training.
format Preprint
id arxiv_https___arxiv_org_abs_2602_19345
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Smooth Gate Functions for Soft Advantage Policy Optimization
Denisov, Egor
Glazyrina, Svetlana
Kryzhanovskiy, Maksim
Ischenko, Roman
Machine Learning
Artificial Intelligence
Group Relative Policy Optimization (GRPO) has significantly advanced the training of large language models and enhanced their reasoning capabilities, while it remains susceptible to instability due to the use of hard clipping. Soft Adaptive Policy Optimization (SAPO) addresses this limitation by replacing clipping with a smooth sigmoid-based gate function, which leads to more stable updates. We have decided to push this theory further and investigate the impact of different gate functions on both training stability and final model performance. We formalize the key properties that admissible gates should satisfy and identify several families of such functions for empirical evaluation. This paper presents an analysis of our findings based on experiments conducted with the Qwen2.5-7B-Instruct model on mathematical reasoning tasks. These results provide practical guidance for designing smoother and more robust policy optimization objectives for large language model training.
title Smooth Gate Functions for Soft Advantage Policy Optimization
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.19345