??? Input argument "x" is undefined.

I want to solve a set of nonlinear equations to get a set of six parameters x(1):x(6).These are my code:

    function F = ParameterEstimation(x)
    T = [1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12];
    for T = [1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12];
      miu(T) = [1;2;3;4;5;6;7;8;9;10;11;12]; %%not the actual values
      sigma(T)=[1;2;3;4;5;6;7;8;9;10;11;12];
      delta(T)=[1;2;3;4;5;6;7;8;9;10;11;12];;
      dryprob(T)=[1;2;3;4;5;6;7;8;9;10;11;12];
    end
    x0 = [0; 0; 0; 0; 0; 0];      
  for T=1:12
     F = [miu(T)-(x(1)*x(6)*(1+(x(2)/x(3)))*(x(5)/(x(4)-1))*T);  
         k1-(2*x(1)*(1+(x(2)/x(3)))*x(6)^2+(x(1)*(1+(x(2)/x(3))*(x(6)^2)*x(3)/((x(3)^2)-1)))*(x(5)^x(4)/(x(4)-1))); 
         k2-(((x(1)*(1+(x(2)/x(3)))* x(2))/((x(3)^2)-1))*(x(5)^x(4)/(x(4)-1)));
         sigma(T) -((((2*x(5))^(2-x(4)))/(x(4)-2)*(k1-(k2/x(3))))-(((2*x(5))^(2-x(4)))/((x(4)-2)*(x(4)-3))*(k1-(k2/x(3)^2)))+(2/((x(4)-2)*(x(4)-3)))*(k1*((T+x(5))^(3-x(4)))-(k2/x(3))*((x(3)*T+x(5))^(3-x(4))))); 
         delta(T) - ((k1/ (x(4)-2)*(x(4)-3))*(x(5)^(3-x(4))+(2*T+x(5)^(3-x(4)))-(2*(T+x(5))^(3-x(4))))+(k2/(x(3)^2*(x(4)-2)*(x(4)-3)))*(2*((x(3)*T+x(5))^(3-x(3))))-x(5)^(3-x(4))-((2*x(3)*T+x(5))^(3-x(4))));
         f1 - ((x(1)*x(5)/(x(3)*(x(4)-1)))*(1+(x(3)*(x(2)+(x(3)/2)))-(1/4)*x(3)*(x(2)+x(3))*(x(2)+2*x(3))+(x(3)*(x(2)+x(3))*(4*x(2)^2+27*x(2)*x(3)+36*x(3)^2))/72)); 
         f2 - (x(1)*x(5)/((x(2)+x(3))*(x(4)-1))*(1-x(2)-x(3)+(3/2)*x(3)*x(2)+x(3)^2+(x(2)^2/2)));
         f3 - ((x(1)*x(5)/((x(2)+x(3))*(x(4)-1)))*(x(5)/(x(5)+T*(x(2)+x(3))))^(x(4)-1)*(1-x(4)-x(3)+(3/2)*x(3)*x(2)+x(3)^2+(x(2)^2/2))); 
         dryprob(T)- (exp(-x(1)*T-f1+f2+f3))]; 
  end
  options=optimset('Display','iter');   % Option to display output
  [x,fval] = fsolve(ParameterEstimation,x0,options);  % Call optimizer

p/s : i am very sorry since the equations are too long. but that's the real equations i hv to solve. Then, i got the error ??? Input argument "x" is undefined. and i dont know what it is and how to fix it :( please help me......

Answer 1

[Image Analyst]

How did you call it? Did you assign a value to x and pass it in, something like this:

x_in = rand(7,1);
Fout = ParameterEstimation(x_in);

[srycandy]

i did assign initial value to every x which is 0.. do i still hv to do as recommended by u?

[Image Analyst]

I don't understand this. You said you did assign initial values, so why are you asking if you still need to assign initial values? Yes, you have to assign initial values for x, even if they're all zero, and then call the function while passing x into the function like I showed.