prp3.m

非常经典的最优化程序

%PRP直接计算算法(不精确一维搜索,k=83,mul_count=19842,sum_count=12722时间略长)
syms x1 x2;
f=50*(x2-x1^2)^2+(1-x1)^2;
v=[x1,x2];
df=jacobian(f,v);
df=df.';
epson=1e-12;x0=[0,0]';g1=subs(df,{x1,x2},{x0(1,1),x0(2,1)});k=0;mul_count=0;sum_count=0;
mul_count=mul_count+7;sum_count=sum_count+4;
while(norm(g1)>epson&k<1000)
    mul_count=mul_count+2;sum_count=sum_count+1;
    if k==0
         p=-g1;
    else
        bta=g1'*(g1-g0)/(g0'*g0); 
        p=-g1+bta*p0;
        mul_count=mul_count+7;sum_count=sum_count+6;
    end
    result=Usearch2(f,x1,x2,df,x0,p);
    arf=result(1);Mul=result(2);Sum=result(3);
    mul_count=mul_count+Mul;sum_count=sum_count+Sum;
    x0=x0+arf*p;
    g0=g1;
    g1=subs(df,{x1,x2},{x0(1,1),x0(2,1)});
    p0=p;
    k=k+1;
    mul_count=mul_count+9;sum_count=sum_count+7;
end;
k
x0
mul_count
sum_count