arXiv AI By Jiale Huang, Zixu Li, Zhiwei Chen, Zhiheng Fu, Jinhe Bi, Yupeng Hu

SetGRPO: Calibrating Grader-Induced Policy Optimization

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SetGRPO is a new method for calibrating grader‑induced policy optimization in rubric‑based reinforcement learning. It introduces three modules—Joint Reward Set Calibration, Geometry‑Guided Safe Recovery, and Selective Risk‑Gated Optimization—to construct uncertainty sets for training coefficients, map them into safe update geometry, and control direction‑reversal risk. Experiments on ten open‑ended benchmarks show that SetGRPO outperforms other training methods on both Qwen3.5 and Llama3.2 models.

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