Muon Splits Loss Stability From Update Reversal During LLM Pretraining

The authors find that Muon can track a stochastic loss-neutral boundary without exhibiting the update-direction reversal associated with gradient descent.

Chinese Tech
Yanzhe Chen · Qifang Zhao · Xiaoxiao Xu · Fanghui Liu

Shanghai Jiao Tong University · Alibaba Inc.

Research Digest··2 min read
Chen and colleagues examine whether the classical edge-of-stability picture for gradient descent also describes language models trained with Muon, an optimizer that replaces matrix gradients with approximately semi-orthogonal directions.

The authors analyze stochastic Muon without momentum and derive a conditional loss-neutral boundary of 2ρ_b/η, where η is the learning rate and ρ_b corrects for the coherence of minibatch-induced Muon directions.

Why this paper

From Alibaba Inc. and Shanghai Jiao Tong University · Released code

In one line

Muon decouples loss neutrality from update reversal, creating separate boundaries in LLM pretraining.

What it released

Code

What we could check

  • ✓Code link in the paper (github.com)
  • ·No weights link found
  • ·No dataset link found
  • ·No compute details found
  • ·No stated limitations found
  • ·No benchmark numbers found

Observed from the paper text and links we have. Absence here means we did not find it, not that it does not exist.

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