Error in using fmincon to minimization

Hello!

Below I place fragment of my program:

coef123=stats123.beta %Those are 10 coefficients from my 3-variable equetion

xx1=linspace(-1,1);

xx2=linspace(-1,1);

xx3=linspace(-1,1);

[x1,x2,x3]=meshgrid(xx1,xx2,xx3);

z12=coef123(1)+coef123(2)*x1+coef123(3)*x2+coef123(4)*x3+coef123(5)*x1.*x2+coef123(6)*x1.*x3+coef123(7)*x2.*x3+coef123(8)*x1.^2+coef123(9)*x2.^2+coef123(10)*x3.^2;

xstart=[-1;-1;-1];

[x,fval]=fmincon(@(x)wartoscminimalna,xstart,[],[],[],[],[-1,-1,-1],[1,1,1]);

disp(x)

disp(fval)

Additionally I have function:

function f=wartoscminimalna(x1,x2,x3)

global coef123

f=-(coef123(1)+coef123(2)*x1+coef123(3)*x2+coef123(4)*x3+coef123(5)*x1.*x2+coef123(6)*x1.*x3+coef123(7)*x2.*x3+coef123(8)*x1.^2+coef123(9)*x2.^2+coef123(10)*x3.^2);

Can someone tell me why it doesn't work? I have this kind of error:

Undefined function 'coef123' for input arguments of
type 'double'.

Error in wartoscminimalna (line 2)
f=-(coef123(1)+coef123(2)*x1+coef123(3)*x2+coef123(4)*x3+coef123(5)*x1.*x2+coef123(6)*x1.*x3+coef123(7)*x2.*x3+coef123(8)*x1.^2+coef123(9)*x2.^2+coef123(10)*x3.^2);
Error in @(x1,x2,x3)wartoscminimalna

Error in fmincon (line 601)
      initVals.f = feval(funfcn{3},X,varargin{:});

Error in programrstool_4D (line 26)
[x,fval]=fmincon(@(x1,x2,x3)wartoscminimalna,xstart,[],[],[],[],[-1,-1,-1],[1,1,1]);

Caused by:
    Failure in initial user-supplied objective
    function evaluation. FMINCON cannot continue.

Please help me with it.

Mateusz

[Matt J]

Please use the

markup button to put your code in a separate font.

[Mateusz]

Sorry for mistake. I've fixed it.

Answer 1

[Matt J]

Your objective should be implemented as follows

function f=wartoscminimalna(x,coeff123)

x1=x(1);
x2=x(2);
x3=x(3);

f=-(coef123(1)+coef123(2)*x1+coef123(3)*x2+coef123(4)*x3+coef123(5)*x1.*x2+coef123(6)*x1.*x3+coef123(7)*x2.*x3+coef123(8)*x1.^2+coef123(9)*x2.^2+coef123(10)*x3.^2);

and then

 [x,fval]=fmincon(@(x)wartoscminimalna(x,stats123.beta),xstart,...
                   [],[],[],[],[-1,-1,-1],[1,1,1]);

[Mateusz]

Great!!! You very helped me. Thank you.