> documenting a function that performs a set of complex scientific simulations.
The example you gave sounds like the problem is deterministic, even if composed of many moving parts. That's one way of looking at complexity.
When I talk about complex problems I'm not just talking about intricate problems. I'm talking about problems where the "problem" is design, not just implementing a design, and that is where LLMs struggle a lot.
Example, I want to design a strongly typed fluent API interface to some functionality. Even knowing how to shape the fluent interface so that is powerful, intuitive, well/strongly typed, and maintainable is a deep art.
The intuitive design constraints that I'm designing under would be hard to even explain to an LLM.