# DPO Family: SimPO + IPO + CPO + RPO + APO — Decision Matrix of 5 Variants

> Source: https://sukruyusufkaya.com/en/learn/fine-tuning-cookbook/ftc-dpo-family-simpo-ipo-cpo-rpo
> Updated: 2026-05-14T14:42:58.257Z
> Category: Fine-Tuning Cookbook (Model-by-Model)
> Module: Part XI — Alignment & Preference Optimization
**TLDR:** DPO family expanded in 2023-2024: SimPO (Meng et al.) — length-normalized, IPO (Azar et al.) — overfit fix, CPO (Xu et al.) — KL ratio fix, RPO (Iterative) — online iterative, APO (anchored). Loss formula for each, when to use which, quick RTX 4090 comparison.