Solving laser Rate Equation using ode 45

Hey! I am kinda new to Matlab and I am currently doing my Project on Semiconductor lasers. I am currently trying to model the rate equations for semiconductor lasers. I have wrote a code but it shows some errors. I have been stuck on this issue for quite some time and it seems that I have done something wrong with ode45. Any type of help is greatly appreciated.

clear

clc

e=1.6e-19;

tr=1e-9;

Ntr=2e7;

g0=4.7e4;

tp=5e-12;

beta=1e-4;

eta=1;

dt=1e-12;

tend=10e-9;

T=0:dt:tend;

N(1)=0;

S(1)=0;

I=7e-3;

for t=1:length(T)-1

N(t+1)=dt*(eta*I/e-N(t)/tr-g0*(N(t)-Ntr)*S(t))+N(t);

S(t+1)=dt*(g0*(N(t)-Ntr)*S(t)-S(t)/tp+beta*N(t)/tr)+S(t);

end

[T,Y] = ODE45(@rate_equation,Y0,T,Y);

subplot 211

plot(T*tr,Y(:,1)*S)

subplot 212

plot(T*tr,Y(:,2)*N)

function dY = rate_eq(T,Y,Y0)

end

Answer 1

[Oriol Brasco]

Try using the following documentation:

https://es.mathworks.com/help/matlab/ref/ode45.html#bu3ugj4

Could you print where you define @rate_equation

[neda m]

thank you for the documentation.

I think I have not defined @rate_equation. could you please tell me how to define that?

[Oriol Brasco]

See this documentation about anonymous functions.

https://es.mathworks.com/help/matlab/matlab_prog/anonymous-functions.html

[neda m]

I'm so sorry, I read the documentation but still don't know how to define @rate_equation in my code.

[Oriol Brasco]

Could you give some information about the function? How the function is defined? Could you print the function to be solved?