tptwic.m

优化设计中的一维搜索方法

function [fx,fy,iter] = Tptwic(func,point)
if length(point)~=3
    error('error input point vector!');
end
falpha1 = subs(func,point(1));
falpha2 = subs(func,point(2));
falpha3 = subs(func,point(3));
C1 = (falpha3-falpha1)/(point(3)-point(1));
C2 = ((falpha2-falpha1)/(point(2)-point(1))-C1)/(point(2)-point(3));
newp = 0.5*(point(1)+point(3)-C1/C2);
fdnewp = subs(diff(func),newp);
iter = 0;
while abs(fdnewp)>10^10*eps
    if fdnewp<0
        limt(1) = newp;
    else
        limt(2) = newp;
    end
    falpha1 = subs(func,point(1));
    falpha2 = subs(func,point(2));
    falpha3 = subs(func,point(3));
    C1 = (falpha3-falpha1)/(point(3)-point(1));
    C2 = ((falpha2-falpha1)/(point(2)-point(1))-C1)/(point(2)-point(3));
    newp = 0.5*(point(1)+point(3)-C1/C2);
    fdnewp = subs(diff(func),newp);
    iter = iter+1;
end
fx = newp;
fy = subs(func,newp);