MATLAB: Fminsearch giving results below initialisation point

fminsearchfunctionMATLABminimise

Hello,
I have a function that I am trying to minimise as follows
function x = kmean_per_dif_fit(img, adam)
x0 = [80,10,1];
tota = @(x)0;
totb = 0;
for i = 1:5
    err = @(x)abs(round(sum(sum((abs(img{1} - x(1))<abs(img{1} - x(2))) == 1))/x(3))-adam(i));
    tota = @(x)tota(x) + err(x);
    totb = totb + adam(i);
end
a = @(x)tota(x)/totb;
x = fminsearch(a,x0)
end
As you can see, i have three unknowns and I try to initialise them at x0 = [80,10,1]
The answers that I get yet, are not within my initilastions
  316.1776   -1.1811    2.6955
any help would be appreciated!

Best Answer

Hello Udi,
I think this can happen because it depends on the function and starting point (Since 'fminseach' function uses heuristic method). The 'fminsearch' uses the Nelder-Mead simplex algorithm for getting the minimum value. Please refer to following documentation for more details on the algorithm.
https://www.mathworks.com/help/matlab/math/optimizing-nonlinear-functions.html#bsgpq6p-11
Related Question