Mathematics

Minimizing Functions of Several Variables

The fminsearch function is similar to fminbnd except that it handles functions of many variables, and you specify a starting vector x₀ rather than a starting interval. fminsearch attempts to return a vector x that is a local minimizer of the mathematical function near this starting vector.

To try fminsearch, create a function three_var of three variables, x, y, and z.

function b = three_var(v)
x = v(1);
y = v(2);
z = v(3);
b = x.^2 + 2.5*sin(y) - z^2*x^2*y^2;

Now find a minimum for this function using x = -0.6, y = -1.2, and z = 0.135 as the starting values.

v = [-0.6 -1.2 0.135];
a = fminsearch(@three_var,v)

a =
    0.0000   -1.5708    0.1803

Minimizing Functions of One Variable

Setting Minimization Options