求助高手

coldspring

clear all
syms z0 z1 x1 x2 y0 n
n=0;
z0=[1 1]
f=x1^2+4*x2^2;
v=[x1,x2];
df=jacobian(f,v);
Q=jacobian(df,v);
g=-df;
eps1=1e-4;
eps2=1e-5;
f0=subs(f, {x1,x2},{z0(1,1),z0(1,2)});
g0=subs(g, {x1,x2},{z0(1,1),z0(1,2)});
h0=[1,0;0,1];
p0=-g0;
z1=z0-((g0*g0')/(g0*Q*g0'))*g0;
f1=subs(f, {x1,x2},{z1(1,1),z1(1,2)});
g1=subs(g, {x1,x2},{z1(1,1),z1(1,2)});
while(f1<0.1)
   
end
x1;
f1;
g1
运行后出现 ??? Function 'lt' is not defined for values of class 'sym'.
怎么解决！！！！！！！！

xjzuo

while(f1<0.1)
   
end

中间什么都没有,怎会不出错?

coldspring

function [a,b,z]=lsliu(f,z0,h)
syms x1 x2 y1 y2 z1 z2
y0=subs(f,[x1,x2],z0);
%n=0
z2=z0+h;
y2=subs(f,[x1,x2],z2);
if(y2>=y0)
z1=z2;
y1=y2;
h=-h;
else
z1=z0;
y1=y0;
z0=z2;
y0=y2;
h=2*h;
end
z2=z0+h;
y2=subs(f,[x1,x2],z2);
while(y2<=y0)
  z1=z0;
  y1=y0;
  z0=z2;
  y0=y2;
  h=2*h;
  z2=z0+h;
  y2=subs(f,[x1,x2],z2);
end
z1=z0;
a=min(z1,z2);
b=max(z1,z2);
eps=0.05;
z1=a+0.382*(b-a);
y1=subs(f,[x1,x2],z1);
z2=a+0.618*(b-a);
y2=subs(f,[x1,x2],z2);
while (abs(b-a)>eps);
   if (y1>=y2)
      a=z1;
      b=b;
      z1=a+0.382*(b-a);
       y1=subs(f,[x1,x2],z1);
      z2=a+0.618*(b-a);
       y2=subs(f,[x1,x2],z2);
   elseif y2>y1
      a=a;
      b=z2;
      x1=a+0.382*(b-a);
       y1=subs(f,[x1,x2],z1);
       z2=a+0.618*(b-a);
       y2=subs(f,[x1,x2],z2);
   end
end
z=(z1+z2)/2;
??? Function 'ge' is not defined for values of class 'sym'.

Error in ==> lsliu at 38
   if (y1>=y2)