I am using Catalyist and DifferentialEquations to study a chemical reaction, but the startup times are somewhat annoying. I have the option, in this case, to write the ODE by hand (thus not requiring Catalyst), and I can also integrate the ODE “by hand”, and with that the complete package would be v…

If you don’t need the SDE/DDE/etc stuff from DiffEq.jl, you can just use OrdinaryDiffEq.jl, which should reduce load times significantly. Likewise, Catalyst just constructs a ReactionSystem from ModelingToolkit.jl, which you can also construct directly.

Those are definitely good suggestions, reducing by 30s the load time. Does it make sense to try to save the ReactionSystem object to pass it directly to the ODEProblem, without having to construct it (and require ModelingToolkit) every time?

The code to translate a ReactionSystem into an ODEProblem lives in MTK.jl, so if you’re saving & loading a ReactionSystem, you’ll have to have MTK.jl loaded to perform that translation. If you can, save the ODEProblem instead and use remake to modify parameters as needed.

[image] stillyslalom: If you can, save the ODEProblem instead and use remake to modify parameters as needed. That is definitely an option. Thanks for the idea.

Is catylist using precompile statements effectively? Part of the answer could be to just fix the load speed.

None of the packages alone is too bad. But each of them takes ~10-15s to load, and also another 20s for the first run of the solve command. (if anything can be improved on the package side I am not in the position to say anything right now).

I’m working on it: https://github.com/SciML/OrdinaryDiffEq.jl/pull/1465

[image] lmiq: Would it be possible, instead of reimplementing the ODEs and the integrator, to load only a small subset of these packages to have a reasonably fast startup time? You can do toexpr(convert(ODESystem,rn)) and it will spit out the code for generating the ODEs, or generate_function,…

That is interesting. I tried that with the code below. But it is the first call to solve that is taking most of the time. Without Catalyst the startup is 10s faster, but the call to solve is taking ~30s here. Seems something is not quite right here, given that you are trying to reduce the first call…

Catalyst + DifferentiaEquations startup time

General Usage

ChrisRackauckas August 13, 2021, 12:14am 14

This is my full response: 22 seconds to 3 and now more: Let's fix all of the DifferentialEquations.jl + universe compile times! .

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Catalyst + DifferentiaEquations startup time

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