What problem does it solve? Aligning language models to human preferences with DPO requires maintaining a separate reference model, doubling memory usage and complicating training pipelines. SimPO removes the reference model entirely while outperforming DPO, but getting the beta, gamma, and learning rate settings right is non-trivial. ## Core Features & Use Cases - Reference-Free Preference Training: Launch SimPO training runs on preference datasets (UltraFeedback, HH-RLHF, math preferences) using accelerate and DeepSpeed ZeRO-3 configs. - Hyperparameter Guidance: Model-size-specific recommendations for learning rate, beta, gamma-beta ratio, and SFT weight, plus troubleshooting for loss divergence, capability forgetting, and OOM. - Dataset Preparation: Preference data formats, quality filtering, deduplication, and synthetic pair generation workflows. - Use Case: Fine-tune Llama 3 8B Instruct on cleaned UltraFeedback preferences with SFT regularization to preserve instruction-following while improving alignment, all on a single node with two A100 GPUs. ## Quick Start Train Mistral 7B on the UltraFeedback preference dataset using SimPO with the recommended default hyperparameters.