Hi, throwing out a Hail Mary here as I have no idea what I am doing. We had/have a working ModelingToolkit model, then suddenly last night it stopped working as the DifferentialEquations.jl package wouldn’t precompile (throwing up errors in nonlinearsolver).
I totally deleted Julia from my computer, reinstalled it, created a new environment, add the packages and all now precompile.
The problem is that my ODESystem now takes 90+ s to form when I run prob=ODEProblem() on my structurally simplified model. I have made no changes to my code and before I reinstalled everything it took about 1 second. It still solves in about 3 seconds, but it’s the forming that takes ages. What’s probably going wrong and how can I fix, delete everything and do a fresh reinstall again?
You could try downgrading ModelingToolkit versions until you find a version where it is fast again. That could help to assess if it is related to some change in MTK.
And if you do find a specific point where it becomes slow it would probably make sense to open an issue on ModelingToolkit with a minimum example that experiences the slow down when changing releases.
Do you have a manifest from before and after, or code to show? I can take a look if you share some code.
We also saw a huge slow down and could fix it by adding this line to Project.toml:
SymbolicUtils = "~3.25"
First, add SymbolicUtils to your project. MTK itself is not the problem.
And if you have code that works well, ALWAYS make a backup of your Manifest.toml file.
If I had to throw a guess out there, do you splat a giant tuple? If so then maybe fix: tuples and arrays of `Symbols` should not be considered symbolic in codegen by AayushSabharwal · Pull Request #735 · JuliaSymbolics/SymbolicUtils.jl · GitHub actually using tuples means that “doing the right thing” (i.e. respecting that you chose to use a tuple) is bad (i.e. giant tuples are really bad for compilation performance, so you probably don’t want to do that, but if you tell us you want a tuple of 100 things we now appropriately respect that).
If you could give us a flamegraph that would be very helpful.