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[ÇóÖú] matlab×îС¶þ³ËÎÊÌâÇóÖú Ôõô¶¨Òå¶à±äÁ¿

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·ÇÏßÐÔ×îС¶þ³ËÎÊÌ⣺minf^2 ÆäÖУ¬ f=[x1+10*x2;sqrt(5)*(x3-x4);(x2-2*x3)^2;sqrt(10)*(x1-x4)^2];x0=[3,-1,0,1]
³ÌÐòÈçÏ£¬¿ÉÒÔÇóµ¥±äÁ¿£¬Ôõô¶¨Òåx=[x1,x2,x3,x4],Çó½âÄØ£¿  Çë¸ßÊÖÖ¸½Ì                        
function fv = Funval( f,varec,varval )
%UNTITLED Summary of this function goes here
%   Detailed explanation goes here
tic;
var = findsym(f);
varc = findsym(varec);
s1=length(var);
s2=length(varc);
m=floor((s1-1)/3+1);
varv=zeros(1,m);
if s1~=s2
    for i=0(s1-1)/3)
        k=findstr(varc,var(3*i+1));
        index=(k-1)/3;
        varv(i+1)=varval(index+1);
    end
    fv=subs(f,var,varv);
else
    fv=subs(f,varec,varval);
end
end
x=[x1,x2,x3,x4];
function [x,minf]= minGN(f,x0,var,eps)%Ä¿±êº¯Êý;f;³õʼµã:x0£¬×Ô±äÁ¿ÏòÁ¿;var,
  %¾«¶È£ºeps£¬Ä¿±êº¯Êý×îСֵʱµÄxÒÔ¼°Ä¿±êº¯Êý×îСֵ
  format long;
  if nargin==4
      eps=1.0e-5;
  end
  S=transpose(f)*f;
  k=length(f);
  n=length(x0);
  x0=transpose(x0);
  tol=1;
  A=jacobian(f,var);
  while tol>eps
      Fx=zeros(k,1);
      for i=1:k
          Fx(i,1)=Funval(f(i),var,x0);
      end
      Sx=Funval(S,var,x0);
      Ax=Funval(A,var,x0);
      gSx=transpose(Ax)*Fx;
      dx=-transpose(Ax)*Fx;
      x0=x0+dx;
      tol=norm(dx);
  end
  x=x0;
  minf=Funval(S,var,x);
  format short;
  toc;
  Iterations;
end
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xuetb

Ìú³æ (³õÈëÎÄ̳)

²¹³ä£ºÅ¼ÔÚmatlabÖÐÊäÈ룺 syms x=[x1 x2 x3 x4];f=[x1+10*x2;sqrt(5)*(x3-x4);(x2-2*x3)^2;sqrt(10)*(x1-x4)^2];x0=[3,-1,0,1];[x,minf]=minGN(f,x0,[x],1.0e-5),S,A,k
´íÎó£º Error using ==> syms at 61
Not a valid variable name.
2Â¥2011-12-05 15:54:01
ÒÑÔÄ   »Ø¸´´ËÂ¥   ¹Ø×¢TA ¸øTA·¢ÏûÏ¢ ËÍTAºì»¨ TAµÄ»ØÌû

zhfzh

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ÓàÔó³É(½ð±Ò+1): лл²ÎÓëÓ¦Öú£¡»¶Ó­³£À´³ÌÐòÓïÑ԰棡 2011-12-08 14:06:03
Äã¿ÉÒÔÓÃstrcat¡¢  evalº¯Êýͨ¹ýÑ­»·À´ÊµÏÖ¶à¸ö±äÁ¿µÄ¶¨Òå
3Â¥2011-12-05 17:11:33
ÒÑÔÄ   »Ø¸´´ËÂ¥   ¹Ø×¢TA ¸øTA·¢ÏûÏ¢ ËÍTAºì»¨ TAµÄ»ØÌû

xuetb

Ìú³æ (³õÈëÎÄ̳)

ÒýÓûØÌû:
3Â¥: Originally posted by zhfzh at 2011-12-05 17:11:33:
Äã¿ÉÒÔÓÃstrcat¡¢  evalº¯Êýͨ¹ýÑ­»·À´ÊµÏÖ¶à¸ö±äÁ¿µÄ¶¨Òå

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