MATLAB Question - Optimization

Hello,

I am an ME STudent currently trying to solve a project with MATLAB.

First of all let me introduce the problem. I just solved a Differential Equation that gives me a vector of Temperatures. As inputs I had a vector of power, air temperature and thermal resistance.

So out of this code I got a calculated temperatur.

I also did measurements on an engine and I got a vector of temperature that I will call measured temperatures.

Now I want to minimize the error between the measured temperatur and the calculated temperature with MATLAB in order to find the best suited Thermal resistance at each point.

Here is my code...it never stops thats the problem

function rest = versuch_optim_2(x,temp,t,y1,f,g,ft,gt)

rest = 0;

f = interp1(ft,f,t,'linear','extrap')'; % Interpolate the data set (ft,f) at time t (linear Method), extrapolate if t is outside of ft
g = interp1(gt,g,t,'linear','extrap')'; % Interpolate the data set (gt,g) at time t (linear Method), extrapolate if t is outside of gt



for i = 1:length(t)

dydt = (f(i)/(800*480) - ((temp(i)-g(i))./(x * 800 *480))) - y1(i);% Evalute ODE at time t

rest = rest + dydt(1).^2;

end

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and I use the following script line to call my code...does anyone know how to solve this...and am I posting this in the wrong place?

[x val]= fminsearch(@(x) versuch_optim_2(x,temp,t,y1,f,g,ft,gt), [1;(1:length(t))'],optimset('MaxFunEvals',10000,'MaxIter',10000))

Thank you

Edouard