Stanford CME295 Transformers & LLMs | Autumn 2025 | Lecture 5 - LLM tuning

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October 31, 2025
This lecture covers:
• Preference tuning
• RLHF overview
• Reward modeling
• RL approaches (PPO and variants)
• DPO

To follow along with the course schedule and syllabus, visit: https://cme295.stanford.edu/syllabus/

Chapters:
00:00:00 Introduction
00:04:50 Preference tuning
00:11:31 Data collection
00:17:43 RLHF overview
00:28:24 Reward model
00:29:46 Bradley-Terry formulation
00:46:02 Reinforcement learning
00:53:54 PPO
00:57:56 Advantage, value function
01:03:39 PPO variants: Clip, KL-penalty
01:16:20 Challenges
01:19:58 On-policy vs off-policy
01:22:43 Best-of-N
01:29:47 DPO

Afshine Amidi is an Adjunct Lecturer at Stanford University.

Shervine Amidi is an Adjunct Lecturer at Stanford University. Receive SMS online on sms24.me

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