domen0.m

来自「一些优化的源代码」· M 代码 · 共 41 行

function t=domen0(a,b)                   %[a,b]为初始区间  t:极小值点   
clc;
e=0.001;
a0=a;
b0=b;
lamda=0.618033989;

rafa1=a0+(1-lamda)*(b0-a0);
rafa2=a0+lamda*(b0-a0);
y1=fai(rafa1);
y2=fai(rafa2);
for i=1:inf
if(y1<=y2)
    if((rafa2-a0)<=e)
        t=rafa1;
        break;
    else
        a0=a0;
        b0=rafa2;
        rafa2=rafa1;
        y2=y1;
        rafa1=a0+(1-lamda)*(b0-a0);
        y1=fai(rafa1);
    end
else
    if((b0-rafa1)<=e)
        t=rafa2;
        break;
    else
        a0=rafa1;
        b0=b0;
        rafa1=rafa2;
        y1=y2;
        rafa2=a0+lamda*(b0-a0);
        y2=fai(rafa2);
    end
end
end
y=fai(t)