Topic

GRPO & Policy Optimization

Group Relative Policy Optimization and related methods update a language-model policy using rewards from sampled response groups rather than a separately learned value critic. The family is attractive for reasoning post-training because it can simplify the RL stack, but performance still depends on sampling, normalization, clipping, KL control, and the quality of the reward signal.

Key concepts

Group-relative advantages

Policy gradients

KL control

Clipping

Latest research

26 items
paper

A Step Harder, Not a Step Too Far: The Benefits and Limits of Curriculum Difficulty Progression in GRPO

Dalian Maritime University

A GSM8K study separates current-policy sample selection from progression between difficulty bands in GRPO. With Qwen2.5-1.5B-Instruct and LoRA, a staged curriculum reaching moderately harder problems improves test accuracy over persistent medium-difficulty selection, while a further difficulty increase reverses the gain across three seeds.

DataCompute
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paper

When KL Regularization Misfires in Group Policy Optimization

Alibaba Group

Zero-Sum Calibrated Policy Optimization (ZCPO) puts reference-policy drift into group-relative update coefficients instead of adding an independent KL loss. The paper analyzes seven potential KL–reward mismatches and reports improved math and long-context performance in its tested configurations.

ComputeData
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paper

GRPODropout: Less is More for Online Reinforcement Learning Rollouts

Harbin Institute of Technology (Shenzhen)

GRPODropout selectively excludes high-probability positive-advantage rollouts from GRPO updates, then recenters retained advantages using old-policy probability weights. With the same generation budget, experiments on Qwen3 models report higher average benchmark accuracy and less entropy collapse than standard GRPO.

DataCompute
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paper

RISED: RubrIcs for agentic multi-environment Selection and sElf-Distillation

National University of Singapore

RISED uses shared behavioral rubrics to select rollout groups across agent environments and to condition an on-policy self-distillation teacher. It improves mean validation pass rate on two small-model backbones, while adding judge inference, teacher forward passes, and rollout oversampling.

DataCompute
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paper

Dependency-Aware Reward Shaping for Agentic Reinforcement Learning

University of Illinois Urbana-Champaign

DARS turns annotated task dependencies into signed step rewards: an unresolved mistake discounts dependent progress while independent work retains credit. Experiments cover household tasks, shopping, retrieval, and mathematics, with the clearest matched gain on a 1.5B ALFWorld agent.

DataCompute
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paper

Score Centering Stabilizes Off-policy Reinforcement Learning

Together AI

Score centering removes an accumulating drift term caused by differences between rollout and training engines. Experiments test when this additive correction stabilizes quantized or stale-policy RL, and when it benefits from being combined with importance sampling.

ComputeRollouts
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paper

Learning to Solve Hard Problems in RL for LLMs by Never Giving Up

Michael Noukhovitch

Never Give Up reallocates rollout compute toward hard problems by quickly filtering easy groups and repeatedly sampling unsolved ones. The study links this adaptive allocation to better learning signals on difficult mathematical and coding tasks.

ComputeRolloutsData
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paper

Proximal Policy Optimization Algorithms

OpenAI

PPO introduces clipped and adaptive objectives intended to make policy-gradient optimization simpler to implement while limiting excessively large policy updates.

RolloutsComputeModels
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