lucidrains/lion-pytorch

Health v2 · maintenance only

Adoption not part of the score

2199 stars · 55 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

A PyTorch implementation of the Lion optimizer (Evolved Sign Momentum), discovered by Google Brain via genetic algorithms and claimed to outperform AdamW. It is a lightweight drop-in optimizer class with tuning guidance for learning rate and beta parameters.

Use cases

• train neural networks with the Lion optimizer in PyTorch
• replace AdamW with a potentially better optimizer
• speed up deep learning model training
• experiment with optimizers discovered via evolutionary search
• tune learning rate and betas for Lion optimizer

When to choose

• you train models in PyTorch and want to try a modern alternative to AdamW
• you are doing language modeling or text-to-image training where Lion has shown positive results
• you want a minimal, easy-to-integrate optimizer implementation

When to avoid

• you need a battle-tested optimizer with guaranteed stability out of the box
• you cannot afford hyperparameter retuning, since Lion requires 3-10x smaller learning rates than AdamW
• you are not using PyTorch

Facets

library · maturity active

machine-learning deep-learning deep-learning machine-learning artificial-intelligence python optimizer pytorch lion-optimizer evolutionary-search training

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markdown · JSON · MCP: product_card(name="lucidrains/lion-pytorch")