README.md

---
license: llama2
base_model:
- codellama/CodeLlama-13b-Instruct-hf
pipeline_tag: text-generation
---

CodeLlama-13b-MORepair is a program repair model fine-tuned from CodeLlama-13b-instruct using a novel multi-objective fine-tuning framework called MOREPAIR. This model is specifically designed to improve automated program repair capabilities by learning both code transformations and repair logic reasoning.

[Paper](https://arxiv.org/abs/2404.12636) | [Code](https://github.com/buaabarty/morepair) | [Colab](https://colab.research.google.com/drive/1vlabdN5Oucm-5kVtMHuEw-kvqDOtB5hg)

## Citation

If you use this model in your research, please cite:
```bibtex
@article{10.1145/3735129,
author = {Yang, Boyang and Tian, Haoye and Ren, Jiadong and Zhang, Hongyu and Klein, Jacques and Bissyande, Tegawende and Le Goues, Claire and Jin, Shunfu},
title = {MORepair: Teaching LLMs to Repair Code via Multi-Objective Fine-Tuning},
year = {2025},
publisher = {Association for Computing Machinery},
issn = {1049-331X},
url = {https://doi.org/10.1145/3735129},
doi = {10.1145/3735129},
journal = {ACM Trans. Softw. Eng. Methodol.},
}
```

## Model Description

- **Base Model**: CodeLlama-13b-instruct
- **Training Technique**: Multi-objective fine-tuning with MOREPAIR framework
- **Supported Languages**: Primarily tested on C++ and Java, but likely generalizes to other languages
- **Primary Use**: Automated program repair
- **License**: Llama 2 Community License
- **Evaluation Benchmarks**: [EvalRepair-Java](https://huggingface.co/datasets/barty/EvalRepair-Java) | [EvalRepair-C++](https://huggingface.co/datasets/barty/EvalRepair-Cpp) | [D4J-Repair](https://huggingface.co/datasets/barty/D4J-Repair) | [SWE-Repair](https://huggingface.co/datasets/barty/SWE-Repair)

## Training Details

### Training Data
- **Dataset**: [TutorLLMCode](https://tutorcode.org/docs/)
- **Size**: 1,535 pairs of buggy and repaired code
- **Nature**: Programming task corrections with LLM-generated repair guidance

### Training Approach
The model was trained using MOREPAIR, which employs:
- Multi-objective learning with two objectives:
  1. Generating repaired code
  2. Producing repaired code with explanatory guidance
- QLoRA fine-tuning (only 1.84% of parameters modified)
- NEFTune for improved generalization
- LLM-generated guidance for understanding repair logic

## Usage

Here's how to use the model with the Hugging Face Transformers library:

### Installation
```bash
pip install transformers torch
```

### Basic Usage
````python
from transformers import AutoModelForCausalLM, AutoTokenizer, pipeline

# Load model and tokenizer
model_name = "barty/CodeLlama-13B-MORepair"
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForCausalLM.from_pretrained(
    model_name,
    device_map="auto",
    load_in_8bit=True,
    torch_dtype=torch.float16
)
pipe = pipeline("text-generation", model=model, tokenizer=tokenizer)

def repair_code(buggy_code, filename="example.java"):
    # Construct prompt in the format model expects
    prompt = f"""[INST] This is an incorrect code({filename}):
```java
{buggy_code}
```
You are a software engineer. Can you repair the incorrect code?
[/INST]
```java
"""
    
    # Calculate token count for length control
    prompt_tokens = len(tokenizer.tokenize(prompt))
    max_new_tokens = 500 - prompt_tokens
    
    # Generate repair
    output = pipe(
        prompt,
        min_length=prompt_tokens + 64,
        max_length=prompt_tokens + max_new_tokens,
        temperature=1.0,
        do_sample=True
    )
    
    # Extract the generated code
    full_text = output[0]['generated_text']
    fixed_code = full_text.split('[/INST]')[1].strip()
    
    return full_text, fixed_code

# Example usage
buggy_code = """
public static int findMinRotated(int[] arr) {
    int left = 0;
    int right = arr.length - 1;
    
    while (left < right) {
        int mid = (left + right) / 2;
        if (arr[mid] > arr[right])
            left = mid;  // Bug: should be mid + 1
        else
            right = mid;
    }
    return arr[left];
}
"""

full_response, fixed_code = repair_code(buggy_code)
print("Fixed code:")
print(fixed_code)
````

### Important Parameters
- `load_in_8bit=True`: Enables 8-bit quantization for efficient inference
- `temperature=1.0`: Controls randomness in generation
- `do_sample=True`: Enables sampling-based generation
- `min_length`: Minimum length of generated text
- `max_length`: Maximum length of generated text

## Limitations

- Performance varies across different programming languages
- May require multiple attempts to generate correct fixes
- Should be used with appropriate test cases to validate repairs
- May not handle very complex or multi-file program repairs

## Technical Specifications

- **Architecture**: Based on CodeLlama-13b-instruct
- **Parameters**: Same as base model (13B)
- **Fine-tuning Method**: QLoRA + NEFTune
- **Context Window**: Same as CodeLlama-13b-instruct
- **Input Format**: Code snippets with optional repair guidance