simpo-training

Optimize language model alignment by directly optimizing log probability differences.

Updated Aug 23, 2026
One-click install
npx skills add https://github.com/matlee0409/cronus --skill simpo-training-matlee0409
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: simpo-training
Source: https://github.com/matlee0409/cronus/tree/main/optional-skills/mlops/simpo
Command: npx skills add https://github.com/matlee0409/cronus --skill simpo-training-matlee0409

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

SimPO provides a reference-free method for aligning language models by directly optimizing the difference between the log-probabilities of chosen and rejected responses, enabling efficient, baseline-free improvement.

Core Features & Use Cases

  • Direct preference optimization without a reference model for training alignment.
  • Supports flexible hyperparameters (learning rate, beta, gamma_beta_ratio, loss_type) and optional SFT regularization to preserve capabilities.
  • Use cases include fine-tuning instruction-following or chat models on domain-specific data with offline datasets and curated preference data.

Quick Start

Launch a single training run with a base model and a prepared preference dataset using the SimPO config to start alignment.

Frequently Asked Questions about simpo-training

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
What is reference-free LLM alignment and how does SimPO work?

Reference-free LLM alignment optimizes language models without a baseline model. SimPO works by directly maximizing the difference in log-probabilities between chosen and rejected responses from preference datasets to efficiently fine-tune model behavior.

How do I fine-tune a language model using a preference dataset without a reference model?

You can fine-tune a language model by applying the SimPO loss formulation to your preference dataset. Configure hyperparameters like learning rate, beta, and gamma_beta_ratio, then launch a training run on your chosen and rejected response pairs.

What hyperparameters should I adjust for preference learning with SimPO?

Key hyperparameters for preference learning include learning rate, beta, gamma_beta_ratio, and loss type. You can also enable optional SFT regularization to preserve the base model's existing capabilities during the alignment process.

Can I use SimPO for domain-specific instruction-following tasks?

Yes, SimPO supports fine-tuning instruction-following and chat models on domain-specific data. You can utilize offline preference datasets like Ultrafeedback or Distilabel Math, and apply optional dataset mixing and data preprocessing steps.

Does reference-free preference optimization prevent catastrophic forgetting during training?

Reference-free preference optimization mitigates capability loss by applying optional SFT regularization. This adds a supervised fine-tuning loss term alongside the chosen and rejected log-probability difference to preserve the model's original performance.