fminsearch应用出错

我的M文件如下：
function [G5]=fun(x);
syms n1 n2 k1 k2 d;
[subwave,nsub]=textread('subout.txt','%f %f');
[filmwave,filmtran]=textread('filmtr.dat','%f %f');
[p,q]=size(subwave);
for j=1:p;
    wavel(j)=subwave(j,1);
    n(j)=n1+n2/((wavel(j))^2);
    k(j)=k1*exp(k2/wavel(j));
    N(j)=n(j)-i*k(j);
    phase(j)=2*pi*N(j)*d/wavel(j);
    ns(j)=nsub(j,1);
    B(j)=cos(phase(j))+ns(j)*i*sin(phase(j))/N(j);
    C(j)=i*N(j)*sin(phase(j))+ns(j)*cos(phase(j));
    T(j)=4*ns(j)/((B(j)+C(j))*conj(B(j)+C(j)));
    ts(j)=1-((1-ns(j))/(1+ns(j)))^2;
    t1(j)=ts(j)*T(j);
    tf(j)=filmtran(j,1)/100;
    difference(j)=(t1(j)-tf(j))^2;
end
G=symsum(difference(j),1,401);
G1=subs(G,n1,sym('x(1)'));
G2=subs(G1,n2,sym('x(2)'));
G3=subs(G2,k1,sym('x(3)'));
G4=subs(G3,k2,sym('x(4)'));
G5=subs(G4,d,sym('x(5)'));

在matlab下运行
>> options=optimset('tolfun',1e-8,'tolx',1e-8);
>> [xmin,value,flag,output]=fminsearch(@fun,[1.7,4000,0.005,400,500],options);

结果出错如下：

??? Conversion to double from sym is not possible.
Error in ==> fminsearch at 175
fv(:,1) = funfcn(x,varargin{:});

哪位高手给看看

fanyushan	2010-07-21 07:47
哪位高人告诉我，错误在哪里呀。M文件复制到命令行，执行，一切正常，就是在求解多元函数0值时，不知道哪里错了。 Hl3XqR JK:mQ_ 53,,%Ue 万分感谢呀

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