[Tutorial] Understanding and Implementing the Muon Optimizer

Hey everyone! :waving_hand:

I’m excited to share a comprehensive tutorial I’ve created on understanding and implementing the Muon optimizer - a recent innovation that’s showing impressive performance improvements over traditional optimizers like AdamW and SGD.

What is Muon?

Muon (MomentUm Orthogonalized by Newton-Schulz) was introduced by Keller Jordan in October 2024 and has quickly gained attention in the optimization community. It specifically targets matrix parameters in neural networks, using Newton-Schulz iterations to orthogonalize gradient updates.

What does this tutorial cover?

  1. The Problem: Why traditional optimizers struggle with skewed singular value distributions

  2. The Solution: How Muon’s matrix orthogonalization addresses this fundamental issue

  3. Practical Implementation: A clean, educational implementation in PyTorch

  4. Performance Analysis: Experimental results showing Muon’s benefits

  5. Lessons Learned: Practical insights from implementing and using Muon

Key Findings

In my experiments, Muon significantly outperformed traditional optimizers:

  • On MNIST, Muon achieved 34% lower loss than AdamW after just 3 epochs

  • On CIFAR-10, Muon reached 80.79% accuracy vs. AdamW’s 71.66% after 5 epochs

  • All this with minimal computational overhead on modern hardware

Why I created this

While exploring Muon, I found there was a gap between the mathematical description in research papers and practical implementation details. This tutorial aims to bridge that gap, providing both theoretical understanding and a working implementation.

I was particularly struck by how a relatively simple mathematical insight - orthogonalizing gradient updates to better utilize the full parameter space - could lead to such significant performance improvements.

Check it out!

:link: Muon Tutorial on Hugging Face

The repository includes a full README explanation and a Colab notebook where you can run all the experiments yourself.

I’d love to hear your thoughts, questions, or experiences if you try Muon in your own projects!

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