How to solve delay differential equations with computed history (not constant)

Greetings!

I'm trying to solve some delay differential equations. The classic example, the Lotka-Volterra predation model illustrates the problem. This is solved in many places around the web*, always using a constant history (as far as I can tell). Usually, the ode system is solved for comparison, then the delayed system, using a constant history, like the last computed point of the ode system. I'd like to use that computed (approximated by, say, ode45, not analytical) solution of the non-delayed system as history, but can't figure out how. Help would be much appreciated.

* e.g., https://www.mathworks.com/matlabcentral/fileexchange/3899-tutorial-on-solving-ddes-with-dde23

Answer 1

[Torsten]

Save the results of the non-delayed ode in arrays T and Y, create an interpolation function

fun_history = @(t) interp1(T,Y,t)

pass this function to the history function of the delay ode solver (e.g. dde23) and evaluate it at the given time instants passed to the history function.

[pedro]

Torsten,

Thank you very much for your assistance. I had to massage your history function a bit, but in the end it worked. Thanks again, for giving me a push in the right direction!