《矩阵分析》Ⅳ

秋秋宝贝耸耸肩: 运行出来了！po主神了

只有七分憨哇: 说x无法识别的，那是字符函数啊，syms x;一下再跑

endeavor98: 请问一下矩阵R是如何定义的？非常感谢

m0_74305919: % Steepset descent method clear; clc; eps=0.005; X=[0 0]'; syms x1 x2 f=x1-x2+2*((x1)^2)+2*x1*x2+(x2)^2; vector=[x1,x2]; [min_x,min_f,k]=Steepset_descent(f,vector,X,eps); disp('Calculation completed!') disp(['Minimal value:',32,num2str(min_f)]) disp(['The vector corresponding to the minimum value:', ... 32,num2str(min_x(1)),32,num2str(min_x(2))]) disp(['Iteration number:',32,num2str(k)]) function [min_x,min_f,k]=Steepset_descent(f,vector,X,eps) syms lamda f=sym(f); vectors=vector.'; grad_=gradient(f,vector); k=0; n=1; while n>0 S=double(subs(grad_,vectors,X)); if norm(S,2)>eps ff=subs(f,vectors,(X-lamda*S)); fun=simplify(diff(ff,lamda)); lamda1=double(solve(fun)); X=double(X-lamda1*S); k=k+1; else break; end end min_x=X; min_f=double(subs(f,vectors,min_x)); end

magic_herb: 输入的初始解向量x0要是列向量，也就是x0=[0,0,0].'