commit 184ca5d3b4776e01cbef929688daff3ea8d4502f Author: ModelHub XC Date: Tue Jun 16 05:42:16 2026 +0800 初始化项目，由ModelHub XC社区提供模型 Model: varunchundru/dpo-qwen2.5-0.5b-halueval Source: Original Platform diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..52373fe --- /dev/null +++ b/.gitattributes @@ -0,0 +1,36 @@ +*.7z filter=lfs diff=lfs merge=lfs -text +*.arrow filter=lfs diff=lfs merge=lfs -text +*.bin filter=lfs diff=lfs merge=lfs -text +*.bz2 filter=lfs diff=lfs merge=lfs -text +*.ckpt filter=lfs diff=lfs merge=lfs -text +*.ftz filter=lfs diff=lfs merge=lfs -text +*.gz filter=lfs diff=lfs merge=lfs -text +*.h5 filter=lfs diff=lfs merge=lfs -text +*.joblib filter=lfs diff=lfs merge=lfs -text +*.lfs.* filter=lfs diff=lfs merge=lfs -text +*.mlmodel filter=lfs diff=lfs merge=lfs -text +*.model filter=lfs diff=lfs merge=lfs -text +*.msgpack filter=lfs diff=lfs merge=lfs -text +*.npy filter=lfs diff=lfs merge=lfs -text +*.npz filter=lfs diff=lfs merge=lfs -text +*.onnx filter=lfs diff=lfs merge=lfs -text +*.ot filter=lfs diff=lfs merge=lfs -text +*.parquet filter=lfs diff=lfs merge=lfs -text +*.pb filter=lfs diff=lfs merge=lfs -text +*.pickle filter=lfs diff=lfs merge=lfs -text +*.pkl filter=lfs diff=lfs merge=lfs -text +*.pt filter=lfs diff=lfs merge=lfs -text +*.pth filter=lfs diff=lfs merge=lfs -text +*.rar filter=lfs diff=lfs merge=lfs -text +*.safetensors filter=lfs diff=lfs merge=lfs -text +saved_model/**/* filter=lfs diff=lfs merge=lfs -text +*.tar.* filter=lfs diff=lfs merge=lfs -text +*.tar filter=lfs diff=lfs merge=lfs -text +*.tflite filter=lfs diff=lfs merge=lfs -text +*.tgz filter=lfs diff=lfs merge=lfs -text +*.wasm filter=lfs diff=lfs merge=lfs -text +*.xz filter=lfs diff=lfs merge=lfs -text +*.zip filter=lfs diff=lfs merge=lfs -text +*.zst filter=lfs diff=lfs merge=lfs -text +*tfevents* filter=lfs diff=lfs merge=lfs -text +tokenizer.json filter=lfs diff=lfs merge=lfs -text diff --git a/README.md b/README.md new file mode 100644 index 0000000..bf297de --- /dev/null +++ b/README.md @@ -0,0 +1,209 @@ +--- +license: apache-2.0 +base_model: Qwen/Qwen2.5-0.5B-Instruct +language: +- en +tags: +- hallucination-reduction +- dpo +- direct-preference-optimization +- qwen2 +- halueval +- nlp +- trl +pipeline_tag: text-generation +datasets: +- pminervini/HaluEval +--- + +# dpo-qwen2.5-0.5b-halueval + +A **Direct Preference Optimization (DPO)** fine-tune of [Qwen2.5-0.5B-Instruct](https://huggingface.co/Qwen/Qwen2.5-0.5B-Instruct) trained to reduce hallucination across grounded QA, dialogue, and summarization tasks. Fine-tuned on preference pairs derived from all three subtasks of the [HaluEval](https://huggingface.co/datasets/pminervini/HaluEval) benchmark. + +This model is the **mitigation component** of a complete hallucination detection + mitigation pipeline built for CS 593 NLP (Purdue University Fort Wayne, Spring 2026). Hallucination rates are measured by passing model generations through a separately fine-tuned DeBERTa detector: [`varunchundru/hallucination-detector-deberta`](https://huggingface.co/varunchundru/hallucination-detector-deberta). + +--- + +## Model Details + +| Field | Value | +|---|---| +| **Base model** | `Qwen/Qwen2.5-0.5B-Instruct` | +| **Fine-tuning method** | Direct Preference Optimization (DPO) via TRL | +| **Training tasks** | QA, Dialogue, Summarization (HaluEval) | +| **Data split** | 70 / 15 / 15 stratified by task | +| **Train pairs** | 21,000 (7,000 per task) | +| **Test samples** | 4,500 (1,500 per task) | +| **Model size** | 0.5B parameters | +| **Hardware** | 1× NVIDIA A100 | +| **Framework** | Hugging Face Transformers + TRL | + +--- + +## Training Details + +### Preference Pair Construction + +Each HaluEval example was converted into a DPO triplet using task-specific formatting: + +| Task | Prompt | Chosen | Rejected | +|---|---|---|---| +| **QA** | System + knowledge + question | `right_answer` | `hallucinated_answer` | +| **Dialogue** | System + knowledge + dialogue history | `right_response` | `hallucinated_response` | +| **Summarization** | System + document | `right_summary` | `hallucinated_summary` | + +**System prompt (QA / Dialogue):** +``` +You are a helpful assistant. Answer based only on the provided knowledge. +Do not invent facts. Be concise. +``` + +**System prompt (Summarization):** +``` +Summarize the following document accurately. +Do not add information not present in the document. +``` + +### Hyperparameters + +| Parameter | Value | +|---|---| +| Epochs | 1 | +| Learning rate | 5e-6 | +| DPO beta (KL penalty) | 0.1 | +| Batch size (train / eval) | 16 | +| Gradient accumulation steps | 1 | +| Max sequence length | 512 | +| Precision | bf16 | +| Best model selection | Lowest eval loss | +| Optimizer | AdamW (default TRL) | + +--- + +## Evaluation + +Hallucination rates are measured on the held-out 15% test split (4,500 examples, 1,500 per task) by passing each model's generation through [`varunchundru/hallucination-detector-deberta`](https://huggingface.co/varunchundru/hallucination-detector-deberta) at a 0.5 probability threshold. + +### Overall Results + +| Model | Hallucination Rate | Mean Hall. Prob | +|---|---|---| +| Qwen2.5-0.5B-Instruct (base) | 85.5% | 0.816 | +| **dpo-qwen2.5-0.5b-halueval (this model)** | **37.7%** | **0.293** | +| Absolute reduction | −47.7 pp | −0.523 | +| **Relative reduction** | **−55.9%** | | + +### Per-Task Breakdown + +| Task | Base Rate | DPO Rate | Relative Reduction | +|---|---|---|---| +| QA | 93.4% | 19.0% | **−79.7%** | +| Summarization | 63.2% | 0.0% | **−100.0%** | +| Dialogue | 99.8% | 94.2% | −5.6% | + +**Notable findings:** +- **QA** sees the largest absolute improvement — the structured knowledge + question format aligns well with DPO training signal. +- **Summarization** hallucination is effectively eliminated on the test set (0.0% rate), likely because the DPO training directly contrasts faithful vs. hallucinated summaries on similar documents. +- **Dialogue** shows minimal improvement (−5.6%). The model still hallucinates in 94.2% of dialogue turns, suggesting that multi-turn conversation is a harder distribution to shift with preference learning at this scale. + +![Hallucination Rate Reduction](dpo_hallucination_reduction.png) + +--- + +## Usage + +```python +from transformers import AutoTokenizer, AutoModelForCausalLM +import torch + +model_id = "varunchundru/dpo-qwen2.5-0.5b-halueval" + +tokenizer = AutoTokenizer.from_pretrained(model_id) +model = AutoModelForCausalLM.from_pretrained( + model_id, + torch_dtype=torch.bfloat16, + device_map="auto", +) +model.eval() + + +def answer_grounded(question: str, knowledge: str, max_new_tokens: int = 150) -> str: + messages = [ + { + "role": "system", + "content": ( + "You are a helpful assistant. Answer based only on the provided knowledge. " + "Do not invent facts. Be concise." + ), + }, + { + "role": "user", + "content": f"Knowledge: {knowledge}\n\nQuestion: {question}", + }, + ] + text = tokenizer.apply_chat_template( + messages, tokenize=False, add_generation_prompt=True + ) + inputs = tokenizer(text, return_tensors="pt").to(model.device) + with torch.no_grad(): + output = model.generate( + **inputs, + max_new_tokens=max_new_tokens, + do_sample=False, + pad_token_id=tokenizer.pad_token_id, + eos_token_id=tokenizer.eos_token_id, + ) + response = tokenizer.decode( + output[0][inputs["input_ids"].shape[1]:], skip_special_tokens=True + ) + return response.strip() + + +# Example +knowledge = "The Eiffel Tower is located in Paris, France, and was completed in 1889." +question = "Where is the Eiffel Tower located and when was it finished?" +print(answer_grounded(question, knowledge)) +``` + +--- + +## Intended Use & Limitations + +**Intended use:** +- Grounded question answering and document summarization where faithfulness to a context is required +- Research on hallucination mitigation via preference learning +- Mitigation component paired with [`varunchundru/hallucination-detector-deberta`](https://huggingface.co/varunchundru/hallucination-detector-deberta) + +**Limitations:** +- **Dialogue performance is weak** — DPO training did not meaningfully reduce hallucination for multi-turn dialogue (94.2% post-DPO rate). The dialogue task may require more training, a larger model, or task-specific preference data. +- Trained for only 1 epoch on 0.5B parameters — further training or a larger base model would likely improve results. +- Hallucination rates are measured by a proxy DeBERTa classifier, not human annotation. +- `max_length=512` during DPO training may truncate long documents in the summarization task. +- Should not be used in high-stakes domains without further validation. + +--- + +## Project Context + +This model is the mitigation component in a four-part hallucination pipeline: + +1. **TF-IDF + Logistic Regression** — Lightweight lexical baseline +2. **Zero-Shot DeBERTa-MNLI** — NLI-based detection without task-specific training (Acc=0.60, F1=0.43, AUROC=0.65) +3. **Fine-Tuned DeBERTa-v3-base** — Task-specific hallucination detector (Acc=0.91, F1=0.91, AUROC=0.98) +4. **DPO Fine-Tuned Qwen2.5-0.5B (this model)** — Reduces hallucination at generation time + +**Authors:** Varun Chundru & Debasmita Biswas +**Course:** CS 593 Natural Language Processing, Purdue University Fort Wayne, Spring 2026 + +--- + +## Citation + +```bibtex +@inproceedings{li2023halueval, + title={HaluEval: A Large-Scale Hallucination Evaluation Benchmark for Large Language Models}, + author={Li, Junyi and Cheng, Xiaoxue and Zhao, Wayne Xin and Nie, Jian-Yun and Wen, Ji-Rong}, + booktitle={Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing}, + year={2023} +} +``` \ No newline at end of file diff --git a/chat_template.jinja b/chat_template.jinja new file mode 100644 index 0000000..bdf7919 --- /dev/null +++ b/chat_template.jinja @@ -0,0 +1,54 @@ +{%- if tools %} + {{- '<|im_start|>system\n' }} + {%- if messages[0]['role'] == 'system' %} + {{- messages[0]['content'] }} + {%- else %} + {{- 'You are Qwen, created by Alibaba Cloud. You are a helpful assistant.' }} + {%- endif %} + {{- "\n\n# Tools\n\nYou may call one or more functions to assist with the user query.\n\nYou are provided with function signatures within XML tags:\n" }} + {%- for tool in tools %} + {{- "\n" }} + {{- tool | tojson }} + {%- endfor %} + {{- "\n\n\nFor each function call, return a json object with function name and arguments within XML tags:\n\n{\"name\": , \"arguments\": }\n<|im_end|>\n" }} +{%- else %} + {%- if messages[0]['role'] == 'system' %} + {{- '<|im_start|>system\n' + messages[0]['content'] + '<|im_end|>\n' }} + {%- else %} + {{- '<|im_start|>system\nYou are Qwen, created by Alibaba Cloud. You are a helpful assistant.<|im_end|>\n' }} + {%- endif %} +{%- endif %} +{%- for message in messages %} + {%- if (message.role == "user") or (message.role == "system" and not loop.first) or (message.role == "assistant" and not message.tool_calls) %} + {{- '<|im_start|>' + message.role + '\n' + message.content + '<|im_end|>' + '\n' }} + {%- elif message.role == "assistant" %} + {{- '<|im_start|>' + message.role }} + {%- if message.content %} + {{- '\n' + message.content }} + {%- endif %} + {%- for tool_call in message.tool_calls %} + {%- if tool_call.function is defined %} + {%- set tool_call = tool_call.function %} + {%- endif %} + {{- '\n\n{"name": "' }} + {{- tool_call.name }} + {{- '", "arguments": ' }} + {{- tool_call.arguments | tojson }} + {{- '}\n' }} + {%- endfor %} + {{- '<|im_end|>\n' }} + {%- elif message.role == "tool" %} + {%- if (loop.index0 == 0) or (messages[loop.index0 - 1].role != "tool") %} + {{- '<|im_start|>user' }} + {%- endif %} + {{- '\n\n' }} + {{- message.content }} + {{- '\n' }} + {%- if loop.last or (messages[loop.index0 + 1].role != "tool") %} + {{- '<|im_end|>\n' }} + {%- endif %} + {%- endif %} +{%- endfor %} +{%- if add_generation_prompt %} + {{- '<|im_start|>assistant\n' }} +{%- endif %} diff --git a/config.json b/config.json new file mode 100644 index 0000000..6bf5a18 --- /dev/null +++ b/config.json @@ -0,0 +1,57 @@ +{ + "architectures": [ + "Qwen2ForCausalLM" + ], + "attention_dropout": 0.0, + "bos_token_id": null, + "dtype": "bfloat16", + "eos_token_id": 151645, + "hidden_act": "silu", + "hidden_size": 896, + "initializer_range": 0.02, + "intermediate_size": 4864, + "layer_types": [ + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention", + "full_attention" + ], + "max_position_embeddings": 32768, + "max_window_layers": 21, + "model_type": "qwen2", + "num_attention_heads": 14, + "num_hidden_layers": 24, + "num_key_value_heads": 2, + "pad_token_id": 151643, + "rms_norm_eps": 1e-06, + "rope_parameters": { + "rope_theta": 1000000.0, + "rope_type": "default" + }, + "sliding_window": null, + "tie_word_embeddings": true, + "transformers_version": "5.6.2", + "use_cache": false, + "use_sliding_window": false, + "vocab_size": 151936 +} diff --git a/generation_config.json b/generation_config.json new file mode 100644 index 0000000..1b2bba9 --- /dev/null +++ b/generation_config.json @@ -0,0 +1,13 @@ +{ + "do_sample": true, + "eos_token_id": [ + 151645, + 151643 + ], + "pad_token_id": 151643, + "repetition_penalty": 1.1, + "temperature": 0.7, + "top_k": 20, + "top_p": 0.8, + "transformers_version": "5.6.2" +} diff --git a/model.safetensors b/model.safetensors new file mode 100644 index 0000000..4031567 --- /dev/null +++ b/model.safetensors @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:cbe723ab261778879e040cd2da94f2df9e80b42827d6e837f7b8ac1e4a81132d +size 988097824 diff --git a/tokenizer.json b/tokenizer.json new file mode 100644 index 0000000..34510ff --- /dev/null +++ b/tokenizer.json @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3fd169731d2cbde95e10bf356d66d5997fd885dd8dbb6fb4684da3f23b2585d8 +size 11421892 diff --git a/tokenizer_config.json b/tokenizer_config.json new file mode 100644 index 0000000..5668a4a --- /dev/null +++ b/tokenizer_config.json @@ -0,0 +1,30 @@ +{ + "add_prefix_space": false, + "backend": "tokenizers", + "bos_token": null, + "clean_up_tokenization_spaces": false, + "eos_token": "<|im_end|>", + "errors": "replace", + "extra_special_tokens": [ + "<|im_start|>", + "<|im_end|>", + "<|object_ref_start|>", + "<|object_ref_end|>", + "<|box_start|>", + "<|box_end|>", + "<|quad_start|>", + "<|quad_end|>", + "<|vision_start|>", + "<|vision_end|>", + "<|vision_pad|>", + "<|image_pad|>", + "<|video_pad|>" + ], + "is_local": true, + "local_files_only": false, + "model_max_length": 131072, + "pad_token": "<|endoftext|>", + "split_special_tokens": false, + "tokenizer_class": "Qwen2Tokenizer", + "unk_token": null +} diff --git a/training_args.bin b/training_args.bin new file mode 100644 index 0000000..62ee5a7 --- /dev/null +++ b/training_args.bin @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:655e60f960ce1703236beca74f97756303c1d7f8544aa98961c9d470f6ba7a41 +size 5905