0.618法的matlab软件实现

0.618法，也称为黄金分割法，是一种用于求解单峰函数最小值的优化算法。下面是使用Matlab实现0.618法的示例代码：

function [x, fval] = golden_section_search(f, a, b, tol)
% Inputs:
%   f: function handle that returns the objective value for a given input x
%   a, b: initial search interval [a, b]
%   tol: tolerance for termination
% Outputs:
%   x: the minimum point found by the algorithm
%   fval: the function value at the minimum point

phi = (1 + sqrt(5))/2; % golden ratio
resphi = 2 - phi;

% Initial guesses for the interval
x1 = a + resphi*(b - a);
x2 = b - resphi*(b - a);

% Evaluate the function at the initial guesses
f1 = f(x1);
f2 = f(x2);

while abs(b - a) > tol
    if f1 < f2
        b = x2;
        x2 = x1;
        x1 = a + resphi*(b - a);
        f2 = f1;
        f1 = f(x1);
    else
        a = x1;
        x1 = x2;
        x2 = b - resphi*(b - a);
        f1 = f2;
        f2 = f(x2);
    end
end

x = (a + b)/2;
fval = f(x);

end

其中，f是待优化的函数句柄，a和b是搜索区间的左右端点，tol是收敛容忍度。函数返回x和fval，分别是搜索出的最小点和该点的函数值。