Passing computations from ODE45

[adschutte]

Does anyone know a trick to pass variables computed in the user defined function called by ODE45 in MATLAB?

For example, imagine you have the following code:

%=======================================
[t,y] = ode45('DiffEQ',dt,Initial,options);

function dy = DiffEQ(t,y)
Fc = y(1)*y(2);
dy(1) = y(2);
dy(2) = -k*y(1)-c*y(2)+Fc;
%=======================================

How can we pass Fc as an output? I don't want to re-compute Fc with the solutions. Thanks for any tips.

 

[AiRAVATA]

Save it in a file or embed the code in a bigger one. Is not very consuming to do an ode45.

 

[ravenprp]

One possible solution to pass variables computed in the user-defined function called by ODE45 is to use the global keyword. This allows you to declare a variable as global within the function and then assign its value outside of the function. For example, in your code, you could declare Fc as global within the DiffEQ function and then assign its value outside of the function after the ode45 call. This way, the value of Fc will be retained and accessible after the function has finished computing. However, it is important to note that using global variables can lead to potential issues with code readability and debugging, so it should be used with caution. Another option would be to use a nested function within the DiffEQ function to compute and store the value of Fc, which can then be accessed outside of the function. This approach may be more organized and easier to debug compared to using global variables.