Changing the shape of the initial value problem in DiffentialEquations.jl and possible performance issues

[ChrisRackauckas]

@Noobie76

But it seems DifferentialEquations.jl only can handle problems of the from ˙X=f(X,t,x)\dot{X} = f(X, t, x) as an input.

No, you’re looking for a mass matrix:

https://docs.juliadiffeq.org/latest/tutorials/advanced_ode_example/#Handling-Mass-Matrices-1