fmin.m

优化设计中的一维搜索方法

% Sifei Liu 
% SA08023001
% 4 Oct 2008
function [fx,fy,iter] = fmin(func, method)
% Find out the optimum point that minimize the function, using different
% approches:
% GoldSect: 黄金分割法;
% TrpInse: 三次插值法;
% Netow: 牛顿法;
% secant: 割线法；
% bisector: 平分线法；
% Tptwic：三点二次插值法；
% fx,fy is the final result,iter is the iteration time;
if nargin ~=2
    error('error input number!');
end
switch method
    case 'GoldSect',
        limt1 = input('lower:');
        limt2 = input('uper:');
        [fx,fy,iter]=GoldSect(func,[limt1,limt2]);
    case 'TrpInse'
        limt1 = input('lower:');
        limt2 = input('uper:');
        [fx,fy,iter]=TrpInse(func,[limt1,limt2]);
    case 'Tptwic'
        a1 = input('The first point:');
        a2 = input('The second point:');
        a3 = input('The third point:');
        [fx,fy,iter] = Tptwic(func, [a1,a2,a3]);
    case 'Newton'
        limt1 = input('lower:');
        limt2 = input('uper:');
        Ini = input('Initial:');
        [fx,fy,iter]=Newton(func,Ini,[limt1,limt2]);
    case 'secant'
        limt1 = input('lower:');
        limt2 = input('uper:');
        [fx,fy,iter] = secant(func,[limt1,limt2]);
    case 'bisector'
        limt1 = input('lower:');
        limt2 = input('uper:');
        [fx,fy,iter] = bisector(func,[limt1,limt2]);
    otherwise
        error('Unknown method!')
end