# Simple Preference Optimization (SimPO) This repository contains the code and released models for our paper [SimPO: Simple Preference Optimization with a Reference-Free Reward](https://arxiv.org/abs/2405.14734). We propose a simpler and more effective preference optimization algorithm than DPO (Direct Preference Optimization) without using a reference model. SimPO outperforms DPO and its latest variants across AlpacaEval 2, MT-Bench, and Arena-Hard benchmarks under various settings. ## 🔗 Quick Links - [SimPO: Simple Preference Optimization with a Reference-Free Reward](#simple-preference-optimization-simpo) - [Released Models](#released-models) - [Install Requirements](#install-requirements) - [Training scripts](#training-scripts) - [Evaluation](#evaluation) - [Bugs or Questions?](#bugs-or-questions) - [Citation](#citation) ## Released Models Below is the full list of models that we evaluate in our preprint. | models | | AE2 LC | AE2 WR | AH | |------------------------------|-----------------------------------------------------------------------------------------------------------|:------:|:------:|:----:| | Mistral Base 7B SFT | [alignment-handbook/zephyr-7b-sft-full](https://huggingface.co/alignment-handbook/zephyr-7b-sft-full) | 8.4 | 6.2 | 1.3 | | Mistral Base 7B DPO (Zephyr) | [princeton-nlp/Mistral-7B-Base-SFT-DPO](https://huggingface.co/princeton-nlp/Mistral-7B-Base-SFT-DPO) | 15.1 | 12.5 | 10.4 | | Mistral Base 7B IPO | [princeton-nlp/Mistral-7B-Base-SFT-IPO](https://huggingface.co/princeton-nlp/Mistral-7B-Base-SFT-IPO) | 11.8 | 9.4 | 7.5 | | Mistral Base 7B KTO | [princeton-nlp/Mistral-7B-Base-SFT-KTO](https://huggingface.co/princeton-nlp/Mistral-7B-Base-SFT-KTO) | 13.1 | 9.1 | 5.6 | | Mistral Base 7B ORPO | [kaist-ai/mistral-orpo-beta](https://huggingface.co/kaist-ai/mistral-orpo-beta) | 14.7 | 12.2 | 7.0 | | Mistral Base 7B R-DPO | [princeton-nlp/Mistral-7B-Base-SFT-RDPO](https://huggingface.co/princeton-nlp/Mistral-7B-Base-SFT-RDPO) | 17.4 | 12.8 | 9.9 | | Mistral Base 7B SimPO | [princeton-nlp/Mistral-7B-Base-SFT-SimPO](https://huggingface.co/princeton-nlp/Mistral-7B-Base-SFT-SimPO) | 21.4 | 20.8 | 16.6 | | Mistral Instruct 7B SFT | [mistralai/Mistral-7B-Instruct-v0.2](https://huggingface.co/mistralai/Mistral-7B-Instruct-v0.2) | 17.1 | 14.7 | 12.6 | | Mistral Instruct 7B DPO | [princeton-nlp/Mistral-7B-Instruct-DPO](https://huggingface.co/princeton-nlp/Mistral-7B-Instruct-DPO) | 26.8 | 24.9 | 16.3 | | Mistral Instruct 7B IPO | [princeton-nlp/Mistral-7B-Instruct-IPO](https://huggingface.co/princeton-nlp/Mistral-7B-Instruct-IPO) | 20.3 | 20.3 | 16.2 | | Mistral Instruct 7B KTO | [princeton-nlp/Mistral-7B-Instruct-KTO](https://huggingface.co/princeton-nlp/Mistral-7B-Instruct-KTO) | 24.5 | 23.6 | 17.9 | | Mistral Instruct 7B ORPO | [princeton-nlp/Mistral-7B-Instruct-ORPO](https://huggingface.co/princeton-nlp/Mistral-7B-Instruct-ORPO) | 24.5 | 24.9 | 20.8 | | Mistral Instruct 7B R-DPO | [princeton-nlp/Mistral-7B-Instruct-RDPO](https://huggingface.co/princeton-nlp/Mistral-7B-Instruct-RDPO) | 27.3 | 24.5 | 16.1 | | Mistral Instruct 7B SimPO | [princeton-nlp/Mistral-7B-Instruct-SimPO](https://huggingface.co/princeton-nlp/Mistral-7B-Instruct-SimPO) | 32.1 | 34.8 | 21.0 | | Llama3 Base 8B SFT | [princeton-nlp/Llama-3-Base-8B-SFT](https://huggingface.co/princeton-nlp/Llama-3-Base-8B-SFT) | 6.2 | 4.6 | 3.3 | | Llama3 Base 8B DPO | [princeton-nlp/Llama-3-Base-8B-SFT-DPO](https://huggingface.co/princeton-nlp/Llama-3-Base-8B-SFT-DPO) | 18.2 | 15.5 | 15.9 | | Llama3 Base 8B IPO | [princeton-nlp/Llama-3-Base-8B-SFT-IPO](https://huggingface.co/princeton-nlp/Llama-3-Base-8B-SFT-IPO) | 14.4 | 14.2 | 17.8 | | Llama3 Base 8B KTO | [princeton-nlp/Llama-3-Base-8B-SFT-KTO](https://huggingface.co/princeton-nlp/Llama-3-Base-8B-SFT-KTO) | 14.2 | 12.4 | 12.5 | | Llama3 Base 8B ORPO | [princeton-nlp/Llama-3-Base-8B-SFT-ORPO](https://huggingface.co/princeton-nlp/Llama-3-Base-8B-SFT-ORPO) | 12.2 | 10.6 | 10.8 | | Llama3 Base 8B R-DPO | [princeton-nlp/Llama-3-Base-8B-SFT-RDPO](https://huggingface.co/princeton-nlp/Llama-3-Base-8B-SFT-RDPO) | 17.6 | 14.4 | 17.2 | | Llama3 Base 8B SimPO | [princeton-nlp/Llama-3-Base-8B-SFT-SimPO](https://huggingface.co/princeton-nlp/Llama-3-Base-8B-SFT-SimPO) | 22.0 | 20.3 | 23.4 | | Llama3 Instruct 8B SFT | [meta-llama/Meta-Llama-3-Instruct-8B](https://huggingface.co/meta-llama/Meta-Llama-3-Instruct-8B) | 26.0 | 25.3 | 22.3 | | Llama3 Instruct 8B DPO | [princeton-nlp/Llama-3-Instruct-8B-DPO](https://huggingface.co/princeton-nlp/Llama-3-Instruct-8B-DPO) | 40.3 | 37.9 | 32.6 | | Llama3 Instruct 8B IPO | [princeton-nlp/Llama-3-Instruct-8B-IPO](https://huggingface.co/princeton-nlp/Llama-3-Instruct-8B-IPO) | 35.6 | 35.6 | 30.5 | | Llama3 Instruct 8B KTO | [princeton-nlp/Llama-3-Instruct-8B-KTO](https://huggingface.co/princeton-nlp/Llama-3-Instruct-8B-KTO) | 33.1 | 31.8 | 26.4 | | Llama3 Instruct 8B ORPO | [princeton-nlp/Llama-3-Instruct-8B-ORPO](https://huggingface.co/princeton-nlp/Llama-3-Instruct-8B-ORPO) | 28.5 | 27.4 | 25.8 | | Llama3 Instruct 8B R-DPO | [princeton-nlp/Llama-3-Instruct-8B-RDPO](https://huggingface.co/princeton-nlp/Llama-3-Instruct-8B-RDPO) | 41.1 | 37.8 | 33.1 | | Llama3 Instruct 8B SimPO | [princeton-nlp/Llama-3-Instruct-8B-SimPO](https://huggingface.co/princeton-nlp/Llama-3-Instruct-8B-SimPO) | 44.7 | 40.5 | 33.8 | Please refer to the [generate.py](generate.py) script for detailed instructions on loading the model with the appropriate chat template. ## Install Requirements Our codebase is built upon the [alignment-handbook repo](https://github.com/huggingface/alignment-handbook). The following steps will guide you through the installation process. First, create a Python virtual environment using e.g. Conda: ```shell conda create -n handbook python=3.10 && conda activate handbook ``` Next, install PyTorch `v2.2.2`. Since this is hardware-dependent, we direct you to the [PyTorch Installation Page](https://pytorch.org/get-started/locally/). You can then install the remaining package dependencies of [alignment-handbook](https://github.com/huggingface/alignment-handbook) as follows: ```shell git clone https://github.com/huggingface/alignment-handbook.git cd ./alignment-handbook/ python -m pip install . ``` You will also need Flash Attention 2 installed, which can be done by running: ```shell python -m pip install flash-attn --no-build-isolation ``` ## Training Scripts We provide four training config files for the four training setups reported in our paper. The training config is set for 8xH100 GPUs. You may need to adjust `num_processes` and `per_device_train_batch_size` based on your computation environment. * Mistral-Base: ```shell ACCELERATE_LOG_LEVEL=info accelerate launch --config_file accelerate_configs/deepspeed_zero3.yaml scripts/run_simpo.py training_configs/mistral-7b-base-simpo.yaml ``` * Mistral-Instruct: ```shell ACCELERATE_LOG_LEVEL=info accelerate launch --config_file accelerate_configs/deepspeed_zero3.yaml scripts/run_simpo.py training_configs/mistral-7b-instruct-simpo.yaml ``` * Llama3-Base: ```shell ACCELERATE_LOG_LEVEL=info accelerate launch --config_file accelerate_configs/deepspeed_zero3.yaml scripts/run_simpo.py training_configs/llama-3-8b-base-simpo.yaml ``` * Llama3-Instruct: ```shell ACCELERATE_LOG_LEVEL=info accelerate launch --config_file accelerate_configs/deepspeed_zero3.yaml scripts/run_simpo.py training_configs/llama-3-8b-instruct-simpo.yaml ``` ## Evaluation We follow the official implementation for evaluation on AlpacaEval 2, Arena-Hard, and MT-Bench, as follows: * AlpacaEval 2: Please refer to the [AlpacaEval repo](https://github.com/tatsu-lab/alpaca_eval) for evaluation. * Arena-Hard: Please refer to to the [Arena-Hard-Auto repo](https://github.com/lm-sys/arena-hard-auto) for evaluation. * MT-Bench: Please refer to the [FastChat repo](https://github.com/lm-sys/FastChat) for evaluation. ## Bugs or Questions? If you have any questions related to the code or the paper, feel free to email Yu (yumeng5@virginia.edu). If you encounter any problems when using the code, or want to report a bug, feel free to open an issue! Please try to specify the problem with details so we can help you better and quicker! ## Citation Please cite our paper if you find the repo helpful in your work: ```bibtex @article{meng2024simpo, title={{SimPO}: Simple Preference Optimization with a Reference-Free Reward}, author={Meng, Yu and Xia, Mengzhou and Chen, Danqi}, year={2024} } ```