I wrote this code and I got this error. (Warning: 8 equations in 4 variables. Warning: Explicit solution could not be found.) How can I fix it?

Question

Busra Tabak 2018-12-15

0
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https://ww2.mathworks.cn/matlabcentral/answers/435936-i-wrote-this-code-and-i-got-this-error-warning-8-equations-in-4-variables-warning-explicit-solu

评论： Busra Tabak 2018-12-16

syms x1 x2 x3 r ll
f=3*(x1+1)+4*(x2-1)+(x3-1);
g=3*x1+4*x2+x3-1;
L=f-r*g;
gradL=gradient(L);
[x1s x2s x3s rs]=solve(gradL==0,[x1 x2 x3 r],'Real',true);
h=.01;
k=.01;
for i=1:numel(x1s)
 fopt=double(subs(f,[x1 x2 x3],[x1s(i) x2s(i) x3s(i)]));
 gc=subs(g,[x1 x2 x3],[x1s(i)+h x2s(i)+k x3s(i)+ll]);
 l=double(solve(gc==0,ll));
 [a j]=min(abs(l));
 l=l(j);
 fnear=double(subs(f,[x1 x2 x3],[x1s(i)+h x2s(i)+k x3s(i)+l]));
 [x1s(i) x2s(i) x3s(i)]
 fopt=sqrt(fopt)
 if fopt<fnear
    disp('min')
 elseif fopt>fnear
    disp('max')
 end
end

Warning: 8 equations in 4 variables. 
> In C:\Program Files\MATLAB\R2013a\toolbox\symbolic\symbolic\symengine.p>symengine at 56
  In mupadengine.mupadengine>mupadengine.evalin at 97
  In mupadengine.mupadengine>mupadengine.feval at 150
  In solve at 172
  In problem1 at 11 
Warning: Explicit solution could not be found. 
> In solve at 179
  In problem1 at 11 