Ode45 change of a value in the equations

Hi everybody, I'm new at matlab, and I have a problem with Ode45: This is my system of equations to solve:

[tout,yout] = ode45(@(t,y) EQS(y,m,T,FN,P,D,gamma,tau), ...

[0:number_of_steps],...

initial_condition)

dPdt = + m .* T .* FN .* P - gamma .* P

dNdt = - m .* T .* FN .* P + tau .* D

dDdt = + gamma .* P - tau .* D

Ode45 works perfectly for this system but I need to change the parameter T (a vector) after a certain number of steps. How can I do that? I have tried to place loops and statemetns into the function "EQS" but Ode doesn't care about them.

[Stephan]

How often does it have to change? How do you dertermine the point of changing the parameter? Please provide what you have done so far.

[Marco Puglia]

Just once. T has to change from a gaussian with center in 15, to a gaussian with center in 20 after the 365th step.

[Stephan]

365th step means t=365 for you?

[Marco Puglia]

yes.

Answer 1

[Stephan]

Do 2 calls of ode45. The first from tspan=[0 365]. Then use the final result from this as initial condition for the second call with the changed T.

[Marco Puglia]

I can't. Yes, it is feasible in that way, but after this initial code, I have to build something with a T that varies periodically from a value to another.

[Stephan]

Please share your code so far