error using nestedfun and fminsearch

Hi,

I want to use fminsearch with a complex function and the nestedfuntion for optimizing B(1) et B(2)

I have the next error: Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 0-by-0.

a,b,c,d,d2 are variables and Table1 , Table2 are two vectors with the same length.

x0=[0,0];

[B,fval]= Eq(x0,c,d,d2,Table2,a,b,Table1);

function [B,fval] = Eq(x0,c,d,d2,Table2,a,b,Table1)

[B,fval]= fminsearch(@nestedfun,x0);

function y = nestedfun(B)

y=[];

if Table2>= min(a,b)

y = sum((Table1 -(c-B(1).*(d-d2)-B(1).*(d2-B(2))-B(1).*(d2.*Table2)).*(Table2-B(2))-(B(1).*(Table2-d2))*(Table2-d2)./2).^2) ;

else if Table2<= (min(a,b))

y = sum((Table1 -(c-B(1).*(d-d2)-B(1).*(d2-B(2))-B(1).*(d2*Table2)).*(Table2-B(2))).^2) ;

end

end

end

end