Error "Supplied objective function must return a scalar value."

Hi,I am trying to minimize a function,but shows an error,

 clc;
clear;
gb=3;gs=8; 
G=[10;10;10;20;30;30;30]; 
Gh=[30;30;30;20;10;10;10]; 
H=[200;200;200;200;100;100;100];   


k=1;
as(k)=3;ab(k)=8;
for i=1:1:length(G)     
    Egm=G(i)-Gh(i);
    if Egm>0
        
        x = [x i];
        elseif Egm<0
    
        y = [y i];
    else
        
        z = [z i];
    end
end

x0=zeros(7,1);

for j=y(1):1:y(length(y))      
F2=@(A)(-(H(j,:).*log(1+A(j,:))+ab(k).*(G(j,:)-A(j,:))));
[A(j,:),fval1(j,:)]=fmincon(F2,x0,[],[],[],[],-100,100)
end
 for j=z(1):1:z(length(z))    
A(j,:)=G(j)                    
 end


if ES>EB  
  f=@(a)((a(1).*(G(x,:)+m)+a(2).*(G(y,:)+p)+gb*(H(x,:)./(a(1)))+gb*(H(y,:)./(a(2)))));
[a,fv] = fmincon(f,X0,[],[],[],[],[3 3],[8 8])
as(k+1)=a(1)   
ab(k+1)=a(2) 
else
end
if (abs(as(k+1)-as(k))>=0.01) && abs(ab(k+1)-ab(k))>=0.01  && rms(abs(Aopt(:,k+1)-Aopt(:,k)))>=0.01
    t=1;
else
k=k+1;
end

Error using fmincon (line 641)

Supplied objective function must return a scalar value.

Error in program23 (line 56)

[a,fv] = fmincon(f,X0,[],[],[],[],[3 3],[8 8])

Can someone explain me why? Please help me to correct this code.

Thanks in advance

Answer 1

[Torsten]

The function you pass to fmincon returns a vector of values, not a scalar.

Maybe you mean

f=@(a) norm(sum(((a(1).*(G(x,:)+m)+a(2).*(G(y,:)+p)+gb*(H(x,:)./(a(1)))+gb*(H(y,:)./(a(2)))))));

or something similar.