User-defined outputs in DifferentialEquations

Hi, is there a possibility to specify outputs that are recorded along the state variables when running a simulation in DifferentialEquations? I could not find anything relating to this in the documentation…

Of course, I can always re-calculate everything from the state-variable traces, but that may be quite some overhead and just is not very handy.

What you’re looking for is explicit algebraic variables, and we don’t have that yet other than via taking control with SavingCallback. You can add to the discussion here: Convenience feature: Include algebraic variables in result · Issue #332 · SciML/DifferentialEquations.jl · GitHub .

It might not be a clean solution, but the overhead should be minimal, if there is any. The majority of the derivatives are not calculated at end points, so I’m not sure you’d benefit much at all from a built-in solution, other than in terms of code cleanliness.

Could DEDataArrays also be used http://docs.juliadiffeq.org/latest/features/diffeq_arrays.html#DEDataArrays-1?

Thanks! So I probably was not searching for the right terms :wink:
I’ll read through the discussion you mentioned…