Hi,
Thanks for writing in. Just to be clear about terminology: for numerically stiff systems of ODEs, there exists a class of (numerical) solvers called "exponential Euler", such as Exponential Rosenbrock-Euler.
There are also linear sets of ODEs, the solution of which can be calculated algebraically (with pen and paper) and will typically end up containing terms like exp(-dt/tau).
Which of these two did you wish to use? In case of the latter, the good news is that that's already implemented and should be working out-of-the-box. For the former, I would be happy to add support for an ERE (or a similar) solver if it makes sense for your model, or you need it to reproduce results. Please let me know what you would deem a suitable ERE solver, preferably one with a C++ interface and an open-source license.
Cheers! Charl
On Mon, Feb 24, 2025, at 15:45, justin.r.davis@essie.ufl.edu wrote:
I've got a version of the HH model (via a NESTML file) which seems to be requiring an exponential Euler solver (ie the one commonly used for e^x dependent biologic systems) to most efficiently solve the equations*. From my reading of the NESTML code generator tools source, only rk45 and forward-Euler are supported. The difference between Euler and Exponential Euler doesn't seem that significant, so I wanted to see if I could get the exponential version implemented....however, what's become unclear to me is whether or not this is a limitation of NEST, NESTML or the underlying solvers and how I'd go about getting a different solver implemented. Are there any guides around on how one would implement a new solver and/or information which would help me figure this out.
thx.
jrd
*=forward Euler does work for some (might work with even smaller timestep) cases, but it requires a time step of 0.01ms. I'm comparing with a Brian2 version of the model running with a 0.1ms time step with it's natively supported exponential Euler solver which is what is making me look into other solvers for my NESTML-based code. _______________________________________________ NEST Users mailing list -- users@nest-simulator.org To unsubscribe send an email to users-leave@nest-simulator.org