Setting `abstol` and `reltol` when solving the Schrödinger equation with OrdinaryDiffEq

[ChrisRackauckas]

Yes that is correct.

@danielwe

(I think this is used because DifferentialEquations allows you to change the length of your state vector during the evolution)

This gives the property that if you have a diagonal ODE and you add more of the same ODE, then you get the same step sizes. It would be weird if bigger ODEs just naturally have smaller dt even if it’s the same equation just repeated a few times.

[danielwe]

@ChrisRackauckas

It would be weird if bigger ODEs just naturally have smaller dt even if it’s the same equation just repeated a few times.

Yeah, makes total sense. The surprising part was that reltol applies elementwise rather than to the overall norm.