How to define a multivariable function (for instance an anonymous function) of a number of variables that varies according to the size of an array variable?

My aim is to compute the point of minimum value for a function which is a determinant of the product of 3 matrices where the columns of the first and third are functions of a variable each.

Answer 1

[Thorsten]

Define your function as

function y = myfun(a,b)

A = [-a a; a -a]; % sample definition
B = rand(2);
C = [-2*b b; -4*b b]

y=det(A*B*C)

Use fminsearch to find the minimum of that function.

[Rui Gonçalves]

Thank you so much for your effort. The problem with this answer is that the number of variables on the call to the function is 2 but in my case is p which is the size of the matrice of data. It's not possible to call the function with x1,x2,...,xp. Do you have any idea of how to circumvent this?