Reinforcement-Learning

On-Policy Distillation: Closing the Gap Between RL and SFT

The two standard post-training methods each leave a gap. Supervised fine-tuning (SFT) has the student imitate sequences a teacher already produced, but training happens on states the student may never actually visit, so errors compound over long generations. Reinforcement learning (RL) samples from the student’s own rollouts, which fixes that mismatch, but the reward is usually a single bit or two per episode. A post Thinking Machines Lab published in October 2025 proposes combining the two: sample trajectories from the student, then have a strong teacher score every token in that trajectory.

Read More

VibeThinker-3B: Packing Verifiable Reasoning into 3 Billion Parameters

“Small model beats big model” papers appear regularly. Usually the claim holds on a specific benchmark under specific conditions, not across the board. WeiboAI’s VibeThinker-3B, published June 15, 2026, follows a similar structure but draws a clearer boundary: the claim is not that a 3B model replaces a frontier generalist. The claim is that verifiable reasoning can be compressed into a small model, while open-domain knowledge and general dialogue still benefit from more parameters.

Read More
Categories
Tags