how to read a function handle parameter when i use ode23

2016 6 27
1 个回答
更新时间：2016 6 28
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Hi all; I use ode23 to solve the ordinary differential equations in the form.
[~,y] = ode23(@(t,x)f(t,x,0, kc, @(t)lookup_u(zdot,t)), [0 2], x00,opt);
My quation is: can I read the value x after ode23 is solved to use these values in a different function? Regards

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回答（1 个）

Torsten
Torsten 2016-6-27

0 个投票

x from above is just a formal paramter. The solution is returned in the y-vector.
Best wishes
Torsten.

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Muna Shehan
Muna Shehan 2016-6-27
Thanks Torsten for your replay. what you say is true, my problem is I need to know x parameter which is calculated via f function
function dx = f(t, x, ~, kc,z)
param.ms = 325;
param.mus = 65;
param.kus = 232.5e3;
u=0;
J = jacobian(t, kc, param);
A = J(1:4,1:4);
B = J(1:4, 5);
b_ramp = [-1; param.ct/param.mus; 0; 0];
if ~isempty(z)
dx= A* x + B * u + b_ramp * z(t);
else
dx = A*x + B*u ;
end
end
based on the previous code can I read the x vector after ode23 is solved. Thank a lot
Muna Shehan
Muna Shehan 2016-6-27
I reviewed MathWorks Support Team question and their answer about " how to pass out extra parameters using ODE23 or ODE45 from the MATLAB ODE suite?".
http://www.mathworks.com/matlabcentral/answers/92701-how-do-i-pass-out-extra-parameters-using-ode23-or-ode45-from-the-matlab-ode-suite
Their answer is clear, and I have some thing similiar where I intent to read and save the return extra parameters, but when I try to fit it to my code I do not know how to deal with function handles for anonymous function. In my case I need to store x when the ode23 is solved. while in Mathworks Support Team their function is
function [dydx k] = myode(x, y)
k = x.^2 + y.^2;
dydx = x + k.*y;
Then, " k" can be obtained via the command
[dydx k] = myode(X, Y);
while in my case the function handles for anonymous function is
function [dx,x] = f(t, x, ~, kc,z)
param.ms = 325;
param.mus = 65;
param.kus = 232.5e3;
u=0;
J = jacobian(t, kc, param);
A = J(1:4,1:4);
B = J(1:4, 5);
b_ramp = [-1; param.ct/param.mus; 0; 0];
if ~isempty(z)
dx= A* x + B * u + b_ramp * z(t);
else
dx = A*x + B*u ;
end
end
My qestion is how I can obtaine x similiar to Math Work Support answer way? Regards
Torsten
Torsten 2016-6-28
I think it's easier if you explain the underlying problem in more detail ...
Best wishes
Torsten.

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Torsten
Torsten
2016-6-28

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