The Hidden Math Bug That Makes AI Unpredictable

Sun, 14 Sep 2025 00:00:00 +0200

This tweet from Awni Hannun demonstrates in one line of MLX code the nondeterminism phenomenon detailed in Thinking Machines’ research. We will explore the PyTorch equivalent that reveals a fundamental issue in AI systems, because I’ve found that tweet extremely helpful to understand what the original blogpost was about.

Here's a one-line code summary in MLX of the @thinkymachines blog post on non-determinism in LLM inference.

I'd guess the difference is larger the lower the precision, as you get larger affects from non-associativity of FP math.

Interestingly, that implies that training at low… pic.twitter.com/jYcDK9GiLn

Determinism on Matt Suiche

The Hidden Math Bug That Makes AI Unpredictable