Hi all, I've proposed the implementation of the modified-Patanka-Runge-Kutta (MPRK) ODE solver. (original message sent at Thu, 27 Aug 2020) I've continued with the development but now I am stuck at a point where decision needs to be made. I've presented more detailed in the github issue <https://github.com/scipy/scipy/issues/12766> but to summarize it quickly: MPRK requires the form of the ODE to be |dy / dt = p(t, y) + d(t, y) where (p/d) is (positive/negative) | instead of the scipy default: || |dy / dt = f(t, y) ||| This opens up three options on how to proceed from here (that I can think of): 1. Allow the new format to be used in solve_ivp. (creates two disjoint ODE solver sets in solve_ivp) 2. Create a new "solve_ivp"-like function. (creates a naming conflict as both methods solve ivp's) 3. Abandon the new solver I personally don't like either of these options very much but I am inclined to the first. Reasons for that are outlined in the github issue. Any thoughts on this? Best, Laurin