function err = err_fit_wtd(x,D,G,N)

%used in var_spher.m

%Weighted sum-of-squares:

%           
%err = sum( (Ni/(Vi)^2)*(Gi - Vi)^2 )
%

v = spher(x,D);

err = sum( (N./(v.^2)).*((G - v).^2) ) ; %Weighted Sum of Squares