QA
Beginner LevelAI, LLMs, Embeddings & MCP

What is Reinforcement Learning from Human Feedback (RLHF) and DPO (Direct Preference Optimization)?

❓ Interview Prompt: Explain alignment, Reward Model training, PPO vs DPO for aligning LLMs with human values.

Base pre-trained LLMs predict raw text continuations. Alignment aligns models to be helpful, honest, and harmless using human preference data:

1. RLHF (Reinforcement Learning from Human Feedback):

•
Humans rank multiple candidate model responses.
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A Reward Model is trained to predict human preference scores.
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The base LLM is fine-tuned using PPO (Proximal Policy Optimization) to maximize scores from the reward model.

2. DPO (Direct Preference Optimization):

Directly optimizes policy weights on preference pairs (Prompt, Chosen_Answer, Rejected_Answer) without needing to train a separate reward model or run complex PPO loops!

Code Implementation Example

json
{
  "prompt": "Explain Quantum Computing simply.",
  "chosen": "Quantum computing uses qubits that exist in superposition, allowing parallel calculations.",
  "rejected": "It is a complex computational paradigm leveraging linear algebra Hilbert spaces."
}
💡DPO training preference pair: chosen vs rejected response.
🎯 Interview Key Takeaway

RLHF and DPO align base completion models to produce safe, helpful, and formatted answers based on human preference data.

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