fminsearch with 2 variables - help please!

Hi,

I want to use fminsearch to find the minimum of 2 variables, but I don't understand how the fminsearch function works in this case. The basic outline of my code is as follows.

function y=myfunction(x,y)
constants not including x & y
m=1
for z=start:spacing:stop
    some calculations involving x & y
    m=m+1
end
y= figure of merit for minimisation

How do I use fminsearch to account for the variables x & y? If I try to use

fminsearch(myfunction(x,y),[x0 y0])

I get an error message

??? Error using ==> fcnchk at 109
FUN must be a function, a valid string expression,
or an inline function object.

Error in ==> fminsearch at 178
funfcn = fcnchk(funfcn,length(varargin));

Please help!

Answer 1

[Baileycat]

Instead of having them as two separate variables, set the problem up with each variable as part of one overall variable.

So, x -> x(1) and y -> x(2)

Then, y=myfunction(x)

[x, fval, exitflag] = fminsearch(@myfunction, [x0;y0])