Optimization toolbox with ode45

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Alessia Nannetti
Alessia Nannetti 2021 年 3 月 15 日
コメント済み: Alan Weiss 2021 年 3 月 16 日
Thank you in advance for the help.
I want to use the optimization toolbox to find the correct value of v to get the condition that Y(end,2) = 0 instead of trying random v values in a for loop.
Does anyone has any suggestions in how can i do that?
here there is the code
v = [13:0.1:15]
for i=1:length(v)
u0 = (v(i)-ev-q*rd); %different values of pi_star at z=0
%having varied Pac
f = @(z,y) [-(a*y(2))./((1-(y(1)./(b*xi_star))).^3);... %dpi_star_dz
-y(1)/c]; %dq_star_dz
[z,Y] = ode45(f,[0 1],[u0 q_0]);
end

回答 (1 件)

Alan Weiss
Alan Weiss 2021 年 3 月 15 日
I guess that I would make a minimization problem for Y(end,2)^2. I don't know what your parameters are, but you can use fminbnd if you have a scalar parameter, or use lsqnonlin or one of the Global Optimization Toolbox solvers for multiple parameters.
  2 件のコメント
Alessia Nannetti
Alessia Nannetti 2021 年 3 月 15 日
the problem is that I want a specific value of v that returns me Y(end,2) = 0 (solution of the second equation of my sistem of odes).
v affects the value of u0 (which is one of my initial condition of the ode45).
I looked up your suggestions but my problem is that by knowing the minimum value (which is Y(end,2) = 0) find the correct value of v that affects the initial condition of my ode45 (u0)
Alan Weiss
Alan Weiss 2021 年 3 月 16 日
Maybe the question is "How can I connect an optimization solver and an ODE solver?" Here are some examples:
It is possible that you would want to use fzero as the optimization solver.
Alan Weiss
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