Function handles and passing parameters to ode solver

20 visualizzazioni (ultimi 30 giorni)
I'm trying to create a function that can be used in an ode solver but can't figure out how to properly pass parameters.
Currently the code is looking like this:
[t,L] = ode45(@f,[0 maxTime],ab);
The function uses the global variables defined in the file, but I'm trying to avoid using those global variables.
function dy = f(t,y)
global c_h c_v k_h k_v l_v l_h g m J_s h myTorque;
dy = zeros(4,1);
%zdotdot
dy(1) = y(2);
dy(2) = ...% Goes on using the variables from above
%thetadotdot
dy(3) = y(4);
dy(4) = ...% Goes on using the variables from above
end
I'd imagine the function looking more like:
function dy = f(t,y,c_h,c_v,k_h,k_v,l_v,l_h,g,m,J_s,h,myTorque)
dy = zeros(4,1);
%zdotdot
dy(1) = y(2);
dy(2) = ...% Goes on using the variables from above
%thetadotdot
dy(3) = y(4);
dy(4) = ...% Goes on using the variables from above
end
How would I call a function like this within the ode solver using the parameters as well?

Risposta accettata

Stephen23
Stephen23 il 18 Feb 2021
Modificato: Stephen23 il 18 Feb 2021
Like this:
c_h = ... some value;
c_v = ... some value;
... all the others variables
myTorque = ... some value;
% Now define an anonymous function with exactly two input arguments:
fun = @(t,y) f(t,y,c_h,c_v,k_h,k_v,l_v,l_h,g,m,J_s,h,myTorque);
% and provide that function handle to the ODE solver:
[t,L] = ode45(fun,[0 maxTime],ab);
  1 Commento
Leon Stangenberg
Leon Stangenberg il 18 Feb 2021
Modificato: Leon Stangenberg il 18 Feb 2021
Yes, thank you for that detailed answer, that was exactly what I couldn't figure out how to do.

Accedi per commentare.

Più risposte (1)

Steven Lord
Steven Lord il 18 Feb 2021
The section of the documentation page for the ode45 function that talks about the odefun input argument links to a page that discusses a couple different techniques for passing additional parameters into the function you specify as the odefun input.
  1 Commento
Leon Stangenberg
Leon Stangenberg il 18 Feb 2021
Thank you, that was what i was looking for, I don't know why I didn't come across that myself.

Accedi per commentare.

Prodotti


Release

R2020b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by