68 lines
2.6 KiB
Markdown
68 lines
2.6 KiB
Markdown
---
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license: llama3.1
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base_model: meta-llama/Llama-3.1-8B-Instruct
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tags:
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- adaptive-rag
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- uncertainty-quantification
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- retrieval-augmented-generation
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- question-answering
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- reinforcement-learning
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- grpo
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language:
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- en
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---
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# uncertain-calibrate
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Fine-tuned from `meta-llama/Llama-3.1-8B-Instruct` via **GRPO reinforcement learning** to emit a special `<uncertain>` token when the model is uncertain during reasoning, enabling uncertainty-guided adaptive retrieval.
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## What it does
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The model reasons step-by-step and inserts `<uncertain>` at any point where it lacks confidence in a fact. A lightweight ridge regression probe (trained on layer-13 hidden states at the `<uncertain>` span) then decides whether to trigger BM25 retrieval and a second-pass generation.
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## Training
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- **Base model**: `meta-llama/Llama-3.1-8B-Instruct`
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- **Training method**: GRPO (Group Relative Policy Optimization) with EM-based reward; the model is rewarded for correct final answers, encouraging it to emit `<uncertain>` in contexts where retrieval would help
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- **Target datasets**: Multi-hop QA (HotpotQA, MuSiQue, 2WikiMultiHopQA) and open-domain QA (NQ, TriviaQA)
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## Retrieval gating (probe)
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A separate ridge regression probe on layer-13 hidden states over `<uncertain>` spans must be trained to use this model for adaptive RAG. The probe AUROC on held-out data is ~0.82. Use the companion probe artifact `uncertain_probe_layer13_alpha3000.pkl` from the [AdaRAGUE repository](https://github.com/JamesJunyuGuo/AdaRAGUE).
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## Evaluation (dev_500_subsampled, 500 questions × 5 datasets, with probe gating)
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| Dataset | EM | F1 | Trigger Rate |
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|---|---|---|---|
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| HotpotQA | 32.6 | 42.7 | 67.4% |
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| MuSiQue | 7.6 | 14.1 | 94.2% |
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| 2WikiMultiHopQA | 26.2 | 29.6 | 59.2% |
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| NQ | 31.4 | 41.0 | 52.0% |
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| TriviaQA | 56.6 | 63.2 | 34.0% |
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| **Overall** | **30.9** | **38.1** | **61.4%** |
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Trigger rate = fraction of questions where the probe decided to retrieve.
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## Intended use
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```python
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from transformers import AutoTokenizer, AutoModelForCausalLM
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tokenizer = AutoTokenizer.from_pretrained("your-username/uncertain-calibrate")
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model = AutoModelForCausalLM.from_pretrained("your-username/uncertain-calibrate")
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SYSTEM = (
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"You are a helpful reasoning assistant. Think step by step. "
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"If at any point you are uncertain about a fact, emit the special token "
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"<uncertain> to signal that you need more information. "
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"End your response with 'Answer: <your answer>' on the last line."
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)
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prompt = tokenizer.apply_chat_template([
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{"role": "system", "content": SYSTEM},
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{"role": "user", "content": "Who directed the film Interstellar?"},
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], tokenize=False, add_generation_prompt=True)
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