If I’m counting correctly, ‘Line 14’ is your ode45 call.
First, forget the global variables. They are likely a significant part of the problem. Pass those variables as extra parameters to your ODE function, if necessary.
Second, it’s difficult to understand your code, and I can’t figure out what ‘time_array’ is doing as a separate variable in your ‘ODEsolver’ function. I would do the ode45 call as:
[t_ode, x] = ode45(@ODESolver, time_array, x0, options);
This also does away with the need to do the later interp1 call, since your ‘ODEsolver’ function is evaluated very close to those time vector elements, and returned at those elements, so the subsequent interp1 call is not necessary.
There are ways to deal with time-varying variables in ODE functions, using interp1 and the returned time value to your ODE function. These are in the documentation on ODE with Time-Dependent Terms (link).
