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skills/mlops/training/grpo-rl-training/README.md
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skills/mlops/training/grpo-rl-training/README.md
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# GRPO/RL Training Skill
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**Expert-level guidance for Group Relative Policy Optimization with TRL**
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## 📁 Skill Structure
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```
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grpo-rl-training/
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├── SKILL.md # Main skill documentation (READ THIS FIRST)
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├── README.md # This file
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├── templates/
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│ └── basic_grpo_training.py # Production-ready training template
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└── examples/
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└── reward_functions_library.py # 20+ reward function examples
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```
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## 🚀 Quick Start
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1. **Read SKILL.md** - Comprehensive guide with all concepts and patterns
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2. **Copy `templates/basic_grpo_training.py`** - Start with working code
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3. **Browse `examples/reward_functions_library.py`** - Pick reward functions for your task
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4. **Modify for your use case** - Adapt dataset, rewards, and config
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## 💡 What's Inside
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### SKILL.md (Main Documentation)
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- Core GRPO concepts and algorithm fundamentals
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- Complete implementation workflow (dataset → rewards → training → deployment)
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- 10+ reward function examples with code
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- Hyperparameter tuning guide
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- Training insights (loss behavior, metrics, debugging)
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- Troubleshooting guide
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- Production best practices
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### Templates
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- **basic_grpo_training.py**: Minimal, production-ready training script
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- Uses Qwen 2.5 1.5B Instruct
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- 3 reward functions (format + correctness)
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- LoRA for efficient training
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- Fully documented and ready to run
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### Examples
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- **reward_functions_library.py**: 20+ battle-tested reward functions
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- Correctness rewards (exact match, fuzzy match, numeric, code execution)
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- Format rewards (XML, JSON, strict/soft)
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- Length rewards (ideal length, min/max)
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- Style rewards (reasoning quality, citations, repetition penalty)
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- Combined rewards (multi-objective optimization)
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- Preset collections for common tasks
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## 📖 Usage for Agents
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When this skill is loaded in your agent's context:
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1. **Always read SKILL.md first** before implementing
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2. **Start simple** - Use length-based reward to validate setup
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3. **Build incrementally** - Add one reward function at a time
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4. **Reference examples** - Copy patterns from reward_functions_library.py
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5. **Monitor training** - Watch reward metrics (not loss!)
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## 🎯 Common Use Cases
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| Task Type | Recommended Rewards | Template |
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|-----------|---------------------|----------|
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| Math reasoning | `MATH_REASONING_REWARDS` preset | basic_grpo_training.py |
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| Code generation | `CODE_GENERATION_REWARDS` preset | Modify dataset in template |
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| Summarization | `SUMMARIZATION_REWARDS` preset | Adjust prompts + rewards |
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| Q&A | `QA_REWARDS` preset | Use fuzzy match + citations |
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## ⚠️ Critical Reminders
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- **Loss goes UP during training** - This is normal (it's KL divergence)
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- **Use 3-5 reward functions** - Single rewards often fail
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- **Test rewards before training** - Debug each function independently
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- **Monitor reward_std** - Should stay > 0.1 (avoid mode collapse)
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- **Start with num_generations=4-8** - Scale up if GPU allows
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## 🔗 External Resources
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- [TRL Documentation](https://huggingface.co/docs/trl)
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- [DeepSeek R1 Paper](https://arxiv.org/abs/2501.12948)
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- [Open R1 Implementation](https://github.com/huggingface/open-r1)
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- [Unsloth (2-3x faster)](https://docs.unsloth.ai/)
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## 📝 Version
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**v1.0.0** - Initial release (January 2025)
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## 👨💻 Maintained By
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Orchestra Research
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For questions or improvements, see https://orchestra.com
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---
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**License:** MIT
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**Last Updated:** January 2025
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575
skills/mlops/training/grpo-rl-training/SKILL.md
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skills/mlops/training/grpo-rl-training/SKILL.md
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---
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name: grpo-rl-training
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description: Expert guidance for GRPO/RL fine-tuning with TRL for reasoning and task-specific model training
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version: 1.0.0
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author: Orchestra Research
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license: MIT
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dependencies: [transformers>=4.47.0, trl>=0.14.0, datasets>=3.2.0, peft>=0.14.0, torch]
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metadata:
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hermes:
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tags: [Post-Training, Reinforcement Learning, GRPO, TRL, RLHF, Reward Modeling, Reasoning, DPO, PPO, Structured Output]
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---
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# GRPO/RL Training with TRL
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Expert-level guidance for implementing Group Relative Policy Optimization (GRPO) using the Transformer Reinforcement Learning (TRL) library. This skill provides battle-tested patterns, critical insights, and production-ready workflows for fine-tuning language models with custom reward functions.
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## When to Use This Skill
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Use GRPO training when you need to:
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- **Enforce specific output formats** (e.g., XML tags, JSON, structured reasoning)
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- **Teach verifiable tasks** with objective correctness metrics (math, coding, fact-checking)
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- **Improve reasoning capabilities** by rewarding chain-of-thought patterns
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- **Align models to domain-specific behaviors** without labeled preference data
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- **Optimize for multiple objectives** simultaneously (format + correctness + style)
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**Do NOT use GRPO for:**
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- Simple supervised fine-tuning tasks (use SFT instead)
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- Tasks without clear reward signals
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- When you already have high-quality preference pairs (use DPO/PPO instead)
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---
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## Core Concepts
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### 1. GRPO Algorithm Fundamentals
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**Key Mechanism:**
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- Generates **multiple completions** for each prompt (group size: 4-16)
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- Compares completions within each group using reward functions
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- Updates policy to favor higher-rewarded responses relative to the group
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**Critical Difference from PPO:**
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- No separate reward model needed
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- More sample-efficient (learns from within-group comparisons)
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- Simpler to implement and debug
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**Mathematical Intuition:**
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```
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For each prompt p:
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1. Generate N completions: {c₁, c₂, ..., cₙ}
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2. Compute rewards: {r₁, r₂, ..., rₙ}
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3. Learn to increase probability of high-reward completions
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relative to low-reward ones in the same group
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```
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### 2. Reward Function Design Philosophy
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**Golden Rules:**
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1. **Compose multiple reward functions** - Each handles one aspect (format, correctness, style)
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2. **Scale rewards appropriately** - Higher weight = stronger signal
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3. **Use incremental rewards** - Partial credit for partial compliance
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4. **Test rewards independently** - Debug each reward function in isolation
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**Reward Function Types:**
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| Type | Use Case | Example Weight |
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|------|----------|----------------|
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| **Correctness** | Verifiable tasks (math, code) | 2.0 (highest) |
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| **Format** | Strict structure enforcement | 0.5-1.0 |
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| **Length** | Encourage verbosity/conciseness | 0.1-0.5 |
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| **Style** | Penalize unwanted patterns | -0.5 to 0.5 |
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---
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## Implementation Workflow
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### Step 1: Dataset Preparation
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**Critical Requirements:**
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- Prompts in chat format (list of dicts with 'role' and 'content')
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- Include system prompts to set expectations
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- For verifiable tasks, include ground truth answers as additional columns
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**Example Structure:**
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```python
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from datasets import load_dataset, Dataset
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SYSTEM_PROMPT = """
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Respond in the following format:
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<reasoning>
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[Your step-by-step thinking]
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</reasoning>
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<answer>
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[Final answer]
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</answer>
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"""
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def prepare_dataset(raw_data):
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"""
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Transform raw data into GRPO-compatible format.
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Returns: Dataset with columns:
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- 'prompt': List[Dict] with role/content (system + user messages)
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- 'answer': str (ground truth, optional but recommended)
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"""
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return raw_data.map(lambda x: {
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'prompt': [
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{'role': 'system', 'content': SYSTEM_PROMPT},
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{'role': 'user', 'content': x['question']}
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],
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'answer': extract_answer(x['raw_answer'])
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})
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```
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**Pro Tips:**
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- Use one-shot or few-shot examples in system prompt for complex formats
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- Keep prompts concise (max_prompt_length: 256-512 tokens)
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- Validate data quality before training (garbage in = garbage out)
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### Step 2: Reward Function Implementation
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**Template Structure:**
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```python
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def reward_function_name(
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prompts, # List[List[Dict]]: Original prompts
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completions, # List[List[Dict]]: Model generations
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answer=None, # Optional: Ground truth from dataset
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**kwargs # Additional dataset columns
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) -> list[float]:
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"""
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Evaluate completions and return rewards.
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Returns: List of floats (one per completion)
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"""
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# Extract completion text
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responses = [comp[0]['content'] for comp in completions]
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# Compute rewards
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rewards = []
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for response in responses:
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score = compute_score(response)
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rewards.append(score)
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return rewards
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```
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**Example 1: Correctness Reward (Math/Coding)**
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```python
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def correctness_reward(prompts, completions, answer, **kwargs):
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"""Reward correct answers with high score."""
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responses = [comp[0]['content'] for comp in completions]
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extracted = [extract_final_answer(r) for r in responses]
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return [2.0 if ans == gt else 0.0
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for ans, gt in zip(extracted, answer)]
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```
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**Example 2: Format Reward (Structured Output)**
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```python
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import re
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def format_reward(completions, **kwargs):
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"""Reward XML-like structured format."""
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pattern = r'<reasoning>.*?</reasoning>\s*<answer>.*?</answer>'
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responses = [comp[0]['content'] for comp in completions]
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return [1.0 if re.search(pattern, r, re.DOTALL) else 0.0
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for r in responses]
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```
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**Example 3: Incremental Format Reward (Partial Credit)**
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```python
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def incremental_format_reward(completions, **kwargs):
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"""Award partial credit for format compliance."""
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responses = [comp[0]['content'] for comp in completions]
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rewards = []
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for r in responses:
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score = 0.0
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if '<reasoning>' in r:
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score += 0.25
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if '</reasoning>' in r:
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score += 0.25
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if '<answer>' in r:
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score += 0.25
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if '</answer>' in r:
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score += 0.25
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# Penalize extra text after closing tag
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if r.count('</answer>') == 1:
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extra_text = r.split('</answer>')[-1].strip()
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score -= len(extra_text) * 0.001
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rewards.append(score)
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return rewards
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```
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**Critical Insight:**
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Combine 3-5 reward functions for robust training. Order matters less than diversity of signals.
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### Step 3: Training Configuration
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**Memory-Optimized Config (Small GPU)**
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```python
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from trl import GRPOConfig
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training_args = GRPOConfig(
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output_dir="outputs/grpo-model",
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# Learning rate
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learning_rate=5e-6, # Lower = more stable
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adam_beta1=0.9,
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adam_beta2=0.99,
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weight_decay=0.1,
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warmup_ratio=0.1,
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lr_scheduler_type='cosine',
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# Batch settings
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per_device_train_batch_size=1,
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gradient_accumulation_steps=4, # Effective batch = 4
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# GRPO-specific
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num_generations=8, # Group size: 8-16 recommended
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max_prompt_length=256,
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max_completion_length=512,
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# Training duration
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num_train_epochs=1,
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max_steps=None, # Or set fixed steps (e.g., 500)
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# Optimization
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bf16=True, # Faster on A100/H100
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optim="adamw_8bit", # Memory-efficient optimizer
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max_grad_norm=0.1,
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# Logging
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logging_steps=1,
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save_steps=100,
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report_to="wandb", # Or "none" for no logging
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)
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```
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**High-Performance Config (Large GPU)**
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```python
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training_args = GRPOConfig(
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output_dir="outputs/grpo-model",
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learning_rate=1e-5,
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per_device_train_batch_size=4,
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gradient_accumulation_steps=2,
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num_generations=16, # Larger groups = better signal
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max_prompt_length=512,
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max_completion_length=1024,
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num_train_epochs=1,
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bf16=True,
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use_vllm=True, # Fast generation with vLLM
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logging_steps=10,
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)
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```
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**Critical Hyperparameters:**
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| Parameter | Impact | Tuning Advice |
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|-----------|--------|---------------|
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| `num_generations` | Group size for comparison | Start with 8, increase to 16 if GPU allows |
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| `learning_rate` | Convergence speed/stability | 5e-6 (safe), 1e-5 (faster, riskier) |
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| `max_completion_length` | Output verbosity | Match your task (512 for reasoning, 256 for short answers) |
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| `gradient_accumulation_steps` | Effective batch size | Increase if GPU memory limited |
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### Step 4: Model Setup and Training
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**Standard Setup (Transformers)**
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```python
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import torch
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from transformers import AutoModelForCausalLM, AutoTokenizer
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from peft import LoraConfig
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from trl import GRPOTrainer
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# Load model
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model_name = "Qwen/Qwen2.5-1.5B-Instruct"
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model = AutoModelForCausalLM.from_pretrained(
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model_name,
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torch_dtype=torch.bfloat16,
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attn_implementation="flash_attention_2", # 2-3x faster
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device_map="auto"
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)
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tokenizer = AutoTokenizer.from_pretrained(model_name)
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tokenizer.pad_token = tokenizer.eos_token
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# Optional: LoRA for parameter-efficient training
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peft_config = LoraConfig(
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r=16, # Rank (higher = more capacity)
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lora_alpha=32, # Scaling factor (typically 2*r)
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target_modules=[
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"q_proj", "k_proj", "v_proj", "o_proj",
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"gate_proj", "up_proj", "down_proj"
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],
|
||||
task_type="CAUSAL_LM",
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lora_dropout=0.05,
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)
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||||
|
||||
# Initialize trainer
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||||
trainer = GRPOTrainer(
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model=model,
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processing_class=tokenizer,
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reward_funcs=[
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incremental_format_reward,
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format_reward,
|
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correctness_reward,
|
||||
],
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||||
args=training_args,
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train_dataset=dataset,
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||||
peft_config=peft_config, # Remove for full fine-tuning
|
||||
)
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||||
|
||||
# Train
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||||
trainer.train()
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||||
|
||||
# Save
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||||
trainer.save_model("final_model")
|
||||
```
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||||
|
||||
**Unsloth Setup (2-3x Faster)**
|
||||
```python
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||||
from unsloth import FastLanguageModel
|
||||
|
||||
model, tokenizer = FastLanguageModel.from_pretrained(
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||||
model_name="google/gemma-3-1b-it",
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||||
max_seq_length=1024,
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||||
load_in_4bit=True,
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||||
fast_inference=True,
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||||
max_lora_rank=32,
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||||
)
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||||
|
||||
model = FastLanguageModel.get_peft_model(
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||||
model,
|
||||
r=32,
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||||
target_modules=["q_proj", "k_proj", "v_proj", "o_proj",
|
||||
"gate_proj", "up_proj", "down_proj"],
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||||
lora_alpha=32,
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||||
use_gradient_checkpointing="unsloth",
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)
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||||
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||||
# Rest is identical to standard setup
|
||||
trainer = GRPOTrainer(model=model, ...)
|
||||
trainer.train()
|
||||
```
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||||
|
||||
---
|
||||
|
||||
## Critical Training Insights
|
||||
|
||||
### 1. Loss Behavior (EXPECTED PATTERN)
|
||||
- **Loss starts near 0 and INCREASES during training**
|
||||
- This is CORRECT - loss measures KL divergence from initial policy
|
||||
- Model is learning (diverging from original behavior to optimize rewards)
|
||||
- Monitor reward metrics instead of loss for progress
|
||||
|
||||
### 2. Reward Tracking
|
||||
Key metrics to watch:
|
||||
- `reward`: Average across all completions
|
||||
- `reward_std`: Diversity within groups (should remain > 0)
|
||||
- `kl`: KL divergence from reference (should grow moderately)
|
||||
|
||||
**Healthy Training Pattern:**
|
||||
```
|
||||
Step Reward Reward_Std KL
|
||||
100 0.5 0.3 0.02
|
||||
200 0.8 0.25 0.05
|
||||
300 1.2 0.2 0.08 ← Good progression
|
||||
400 1.5 0.15 0.12
|
||||
```
|
||||
|
||||
**Warning Signs:**
|
||||
- Reward std → 0 (model collapsing to single response)
|
||||
- KL exploding (> 0.5) (diverging too much, reduce LR)
|
||||
- Reward stuck (reward functions too harsh or model capacity issue)
|
||||
|
||||
### 3. Common Pitfalls and Solutions
|
||||
|
||||
| Problem | Symptom | Solution |
|
||||
|---------|---------|----------|
|
||||
| **Mode collapse** | All completions identical | Increase `num_generations`, add diversity penalty |
|
||||
| **No learning** | Flat rewards | Check reward function logic, increase LR |
|
||||
| **OOM errors** | GPU memory exceeded | Reduce `num_generations`, enable gradient checkpointing |
|
||||
| **Slow training** | < 1 it/s | Enable `use_vllm=True`, use Unsloth, reduce seq length |
|
||||
| **Format ignored** | Model doesn't follow structure | Increase format reward weight, add incremental rewards |
|
||||
|
||||
---
|
||||
|
||||
## Advanced Patterns
|
||||
|
||||
### 1. Multi-Stage Training
|
||||
For complex tasks, train in stages:
|
||||
|
||||
```python
|
||||
# Stage 1: Format compliance (epochs=1)
|
||||
trainer_stage1 = GRPOTrainer(
|
||||
model=model,
|
||||
reward_funcs=[incremental_format_reward, format_reward],
|
||||
...
|
||||
)
|
||||
trainer_stage1.train()
|
||||
|
||||
# Stage 2: Correctness (epochs=1)
|
||||
trainer_stage2 = GRPOTrainer(
|
||||
model=model,
|
||||
reward_funcs=[format_reward, correctness_reward],
|
||||
...
|
||||
)
|
||||
trainer_stage2.train()
|
||||
```
|
||||
|
||||
### 2. Adaptive Reward Scaling
|
||||
```python
|
||||
class AdaptiveReward:
|
||||
def __init__(self, base_reward_func, initial_weight=1.0):
|
||||
self.func = base_reward_func
|
||||
self.weight = initial_weight
|
||||
|
||||
def __call__(self, *args, **kwargs):
|
||||
rewards = self.func(*args, **kwargs)
|
||||
return [r * self.weight for r in rewards]
|
||||
|
||||
def adjust_weight(self, success_rate):
|
||||
"""Increase weight if model struggling, decrease if succeeding."""
|
||||
if success_rate < 0.3:
|
||||
self.weight *= 1.2
|
||||
elif success_rate > 0.8:
|
||||
self.weight *= 0.9
|
||||
```
|
||||
|
||||
### 3. Custom Dataset Integration
|
||||
```python
|
||||
def load_custom_knowledge_base(csv_path):
|
||||
"""Example: School communication platform docs."""
|
||||
import pandas as pd
|
||||
df = pd.read_csv(csv_path)
|
||||
|
||||
dataset = Dataset.from_pandas(df).map(lambda x: {
|
||||
'prompt': [
|
||||
{'role': 'system', 'content': CUSTOM_SYSTEM_PROMPT},
|
||||
{'role': 'user', 'content': x['question']}
|
||||
],
|
||||
'answer': x['expert_answer']
|
||||
})
|
||||
return dataset
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Deployment and Inference
|
||||
|
||||
### Save and Merge LoRA
|
||||
```python
|
||||
# Merge LoRA adapters into base model
|
||||
if hasattr(trainer.model, 'merge_and_unload'):
|
||||
merged_model = trainer.model.merge_and_unload()
|
||||
merged_model.save_pretrained("production_model")
|
||||
tokenizer.save_pretrained("production_model")
|
||||
```
|
||||
|
||||
### Inference Example
|
||||
```python
|
||||
from transformers import pipeline
|
||||
|
||||
generator = pipeline(
|
||||
"text-generation",
|
||||
model="production_model",
|
||||
tokenizer=tokenizer
|
||||
)
|
||||
|
||||
result = generator(
|
||||
[
|
||||
{'role': 'system', 'content': SYSTEM_PROMPT},
|
||||
{'role': 'user', 'content': "What is 15 + 27?"}
|
||||
],
|
||||
max_new_tokens=256,
|
||||
do_sample=True,
|
||||
temperature=0.7,
|
||||
top_p=0.9
|
||||
)
|
||||
print(result[0]['generated_text'])
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Best Practices Checklist
|
||||
|
||||
**Before Training:**
|
||||
- [ ] Validate dataset format (prompts as List[Dict])
|
||||
- [ ] Test reward functions on sample data
|
||||
- [ ] Calculate expected max_prompt_length from data
|
||||
- [ ] Choose appropriate num_generations based on GPU memory
|
||||
- [ ] Set up logging (wandb recommended)
|
||||
|
||||
**During Training:**
|
||||
- [ ] Monitor reward progression (should increase)
|
||||
- [ ] Check reward_std (should stay > 0.1)
|
||||
- [ ] Watch for OOM errors (reduce batch size if needed)
|
||||
- [ ] Sample generations every 50-100 steps
|
||||
- [ ] Validate format compliance on holdout set
|
||||
|
||||
**After Training:**
|
||||
- [ ] Merge LoRA weights if using PEFT
|
||||
- [ ] Test on diverse prompts
|
||||
- [ ] Compare to baseline model
|
||||
- [ ] Document reward weights and hyperparameters
|
||||
- [ ] Save reproducibility config
|
||||
|
||||
---
|
||||
|
||||
## Troubleshooting Guide
|
||||
|
||||
### Debugging Workflow
|
||||
1. **Isolate reward functions** - Test each independently
|
||||
2. **Check data distribution** - Ensure diversity in prompts
|
||||
3. **Reduce complexity** - Start with single reward, add gradually
|
||||
4. **Monitor generations** - Print samples every N steps
|
||||
5. **Validate extraction logic** - Ensure answer parsing works
|
||||
|
||||
### Quick Fixes
|
||||
```python
|
||||
# Debug reward function
|
||||
def debug_reward(completions, **kwargs):
|
||||
responses = [comp[0]['content'] for comp in completions]
|
||||
for i, r in enumerate(responses[:2]): # Print first 2
|
||||
print(f"Response {i}: {r[:200]}...")
|
||||
return [1.0] * len(responses) # Dummy rewards
|
||||
|
||||
# Test without training
|
||||
trainer = GRPOTrainer(..., reward_funcs=[debug_reward])
|
||||
trainer.generate_completions(dataset[:1]) # Generate without updating
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## References and Resources
|
||||
|
||||
**Official Documentation:**
|
||||
- TRL GRPO Trainer: https://huggingface.co/docs/trl/grpo_trainer
|
||||
- DeepSeek R1 Paper: https://arxiv.org/abs/2501.12948
|
||||
- Unsloth Docs: https://docs.unsloth.ai/
|
||||
|
||||
**Example Repositories:**
|
||||
- Open R1 Implementation: https://github.com/huggingface/open-r1
|
||||
- TRL Examples: https://github.com/huggingface/trl/tree/main/examples
|
||||
|
||||
**Recommended Reading:**
|
||||
- Progressive Disclosure Pattern for agent instructions
|
||||
- Reward shaping in RL (Ng et al.)
|
||||
- LoRA paper (Hu et al., 2021)
|
||||
|
||||
---
|
||||
|
||||
## Usage Instructions for Agents
|
||||
|
||||
When this skill is loaded:
|
||||
|
||||
1. **Read this entire file** before implementing GRPO training
|
||||
2. **Start with the simplest reward function** (e.g., length-based) to validate setup
|
||||
3. **Use the templates** in `templates/` directory as starting points
|
||||
4. **Reference examples** in `examples/` for task-specific implementations
|
||||
5. **Follow the workflow** sequentially (don't skip steps)
|
||||
6. **Debug incrementally** - add one reward function at a time
|
||||
|
||||
**Critical Reminders:**
|
||||
- Always use multiple reward functions (3-5 is optimal)
|
||||
- Monitor reward metrics, not loss
|
||||
- Test reward functions before training
|
||||
- Start small (num_generations=4), scale up gradually
|
||||
- Save checkpoints frequently (every 100 steps)
|
||||
|
||||
This skill is designed for **expert-level implementation**. Beginners should start with supervised fine-tuning before attempting GRPO.
|
||||
|
||||
|
||||
|
||||
@@ -0,0 +1,228 @@
|
||||
"""
|
||||
Basic GRPO Training Template
|
||||
=============================
|
||||
|
||||
A minimal, production-ready template for GRPO training with TRL.
|
||||
Adapt this for your specific task by modifying:
|
||||
1. Dataset loading (get_dataset function)
|
||||
2. Reward functions (reward_*_func)
|
||||
3. System prompt (SYSTEM_PROMPT)
|
||||
4. Hyperparameters (GRPOConfig)
|
||||
"""
|
||||
|
||||
import torch
|
||||
import re
|
||||
from datasets import load_dataset
|
||||
from transformers import AutoModelForCausalLM, AutoTokenizer
|
||||
from peft import LoraConfig
|
||||
from trl import GRPOTrainer, GRPOConfig
|
||||
|
||||
# ==================== CONFIGURATION ====================
|
||||
|
||||
MODEL_NAME = "Qwen/Qwen2.5-1.5B-Instruct"
|
||||
OUTPUT_DIR = "outputs/grpo-model"
|
||||
MAX_PROMPT_LENGTH = 256
|
||||
MAX_COMPLETION_LENGTH = 512
|
||||
|
||||
SYSTEM_PROMPT = """
|
||||
Respond in the following format:
|
||||
<reasoning>
|
||||
[Your step-by-step thinking]
|
||||
</reasoning>
|
||||
<answer>
|
||||
[Final answer]
|
||||
</answer>
|
||||
"""
|
||||
|
||||
# ==================== DATASET ====================
|
||||
|
||||
def get_dataset(split="train"):
|
||||
"""
|
||||
Load and prepare your dataset.
|
||||
|
||||
Returns: Dataset with columns:
|
||||
- 'prompt': List[Dict] with role/content
|
||||
- 'answer': str (ground truth, optional)
|
||||
"""
|
||||
# Example: GSM8K math dataset
|
||||
data = load_dataset('openai/gsm8k', 'main')[split]
|
||||
|
||||
def process_example(x):
|
||||
# Extract ground truth answer
|
||||
answer = x['answer'].split('####')[1].strip() if '####' in x['answer'] else None
|
||||
|
||||
return {
|
||||
'prompt': [
|
||||
{'role': 'system', 'content': SYSTEM_PROMPT},
|
||||
{'role': 'user', 'content': x['question']}
|
||||
],
|
||||
'answer': answer
|
||||
}
|
||||
|
||||
return data.map(process_example)
|
||||
|
||||
# ==================== HELPER FUNCTIONS ====================
|
||||
|
||||
def extract_xml_tag(text: str, tag: str) -> str:
|
||||
"""Extract content between XML tags."""
|
||||
pattern = f'<{tag}>(.*?)</{tag}>'
|
||||
match = re.search(pattern, text, re.DOTALL)
|
||||
return match.group(1).strip() if match else ""
|
||||
|
||||
def extract_answer(text: str) -> str:
|
||||
"""Extract the final answer from structured output."""
|
||||
return extract_xml_tag(text, 'answer')
|
||||
|
||||
# ==================== REWARD FUNCTIONS ====================
|
||||
|
||||
def correctness_reward_func(prompts, completions, answer, **kwargs):
|
||||
"""
|
||||
Reward correct answers.
|
||||
Weight: 2.0 (highest priority)
|
||||
"""
|
||||
responses = [comp[0]['content'] for comp in completions]
|
||||
extracted = [extract_answer(r) for r in responses]
|
||||
return [2.0 if ans == gt else 0.0 for ans, gt in zip(extracted, answer)]
|
||||
|
||||
def format_reward_func(completions, **kwargs):
|
||||
"""
|
||||
Reward proper XML format.
|
||||
Weight: 0.5
|
||||
"""
|
||||
pattern = r'<reasoning>.*?</reasoning>\s*<answer>.*?</answer>'
|
||||
responses = [comp[0]['content'] for comp in completions]
|
||||
return [0.5 if re.search(pattern, r, re.DOTALL) else 0.0 for r in responses]
|
||||
|
||||
def incremental_format_reward_func(completions, **kwargs):
|
||||
"""
|
||||
Incremental reward for partial format compliance.
|
||||
Weight: up to 0.5
|
||||
"""
|
||||
responses = [comp[0]['content'] for comp in completions]
|
||||
rewards = []
|
||||
|
||||
for r in responses:
|
||||
score = 0.0
|
||||
if '<reasoning>' in r:
|
||||
score += 0.125
|
||||
if '</reasoning>' in r:
|
||||
score += 0.125
|
||||
if '<answer>' in r:
|
||||
score += 0.125
|
||||
if '</answer>' in r:
|
||||
score += 0.125
|
||||
|
||||
# Penalize extra content after closing tag
|
||||
if '</answer>' in r:
|
||||
extra = r.split('</answer>')[-1].strip()
|
||||
score -= len(extra) * 0.001
|
||||
|
||||
rewards.append(score)
|
||||
|
||||
return rewards
|
||||
|
||||
# ==================== MODEL SETUP ====================
|
||||
|
||||
def setup_model_and_tokenizer():
|
||||
"""Load model and tokenizer with optimizations."""
|
||||
model = AutoModelForCausalLM.from_pretrained(
|
||||
MODEL_NAME,
|
||||
torch_dtype=torch.bfloat16,
|
||||
attn_implementation="flash_attention_2",
|
||||
device_map="auto"
|
||||
)
|
||||
|
||||
tokenizer = AutoTokenizer.from_pretrained(MODEL_NAME)
|
||||
tokenizer.pad_token = tokenizer.eos_token
|
||||
|
||||
return model, tokenizer
|
||||
|
||||
def get_peft_config():
|
||||
"""LoRA configuration for parameter-efficient training."""
|
||||
return LoraConfig(
|
||||
r=16,
|
||||
lora_alpha=32,
|
||||
target_modules=[
|
||||
"q_proj", "k_proj", "v_proj", "o_proj",
|
||||
"gate_proj", "up_proj", "down_proj"
|
||||
],
|
||||
task_type="CAUSAL_LM",
|
||||
lora_dropout=0.05,
|
||||
)
|
||||
|
||||
# ==================== TRAINING ====================
|
||||
|
||||
def main():
|
||||
"""Main training function."""
|
||||
|
||||
# Load data
|
||||
print("Loading dataset...")
|
||||
dataset = get_dataset()
|
||||
print(f"Dataset size: {len(dataset)}")
|
||||
|
||||
# Setup model
|
||||
print("Loading model...")
|
||||
model, tokenizer = setup_model_and_tokenizer()
|
||||
|
||||
# Training configuration
|
||||
training_args = GRPOConfig(
|
||||
output_dir=OUTPUT_DIR,
|
||||
run_name="grpo-training",
|
||||
|
||||
# Learning rate
|
||||
learning_rate=5e-6,
|
||||
adam_beta1=0.9,
|
||||
adam_beta2=0.99,
|
||||
weight_decay=0.1,
|
||||
warmup_ratio=0.1,
|
||||
lr_scheduler_type='cosine',
|
||||
|
||||
# Batch settings
|
||||
per_device_train_batch_size=1,
|
||||
gradient_accumulation_steps=4,
|
||||
|
||||
# GRPO specific
|
||||
num_generations=8,
|
||||
max_prompt_length=MAX_PROMPT_LENGTH,
|
||||
max_completion_length=MAX_COMPLETION_LENGTH,
|
||||
|
||||
# Training duration
|
||||
num_train_epochs=1,
|
||||
|
||||
# Optimization
|
||||
bf16=True,
|
||||
optim="adamw_8bit",
|
||||
max_grad_norm=0.1,
|
||||
|
||||
# Logging
|
||||
logging_steps=1,
|
||||
save_steps=100,
|
||||
report_to="wandb", # Change to "none" to disable logging
|
||||
)
|
||||
|
||||
# Initialize trainer
|
||||
trainer = GRPOTrainer(
|
||||
model=model,
|
||||
processing_class=tokenizer,
|
||||
reward_funcs=[
|
||||
incremental_format_reward_func,
|
||||
format_reward_func,
|
||||
correctness_reward_func,
|
||||
],
|
||||
args=training_args,
|
||||
train_dataset=dataset,
|
||||
peft_config=get_peft_config(),
|
||||
)
|
||||
|
||||
# Train
|
||||
print("Starting training...")
|
||||
trainer.train()
|
||||
|
||||
# Save final model
|
||||
print(f"Saving model to {OUTPUT_DIR}/final")
|
||||
trainer.save_model(f"{OUTPUT_DIR}/final")
|
||||
|
||||
print("Training complete!")
|
||||
|
||||
if __name__ == "__main__":
|
||||
main()
|
||||
Reference in New Issue
Block a user