function err = gauss_errfn(fitparams,x,y);
%
% function err = gauss_errfn(fitparams,x,y);
% 
% Returns the error, err, between the z-gaussian function and the 
% input data.  Assumes the input data is of the form where x is 
% the grid, and y is the Gaussian.
%
% Input variable fitparams should be of the following form:
%
% fitparams = [A, xo, sigma], 
%
% where we are fitting to a gaussian of the form:
%
% y = A*exp(-(x-xo)^2 / (2*sigma^2))
%
%
% Written by Miles A. Sundermeyer, 2/1/06

% parse fitparams
A = fitparams(1);
xo = fitparams(2);
sigma = fitparams(3);

% compute the function associated with the fit params
yfit =  A*exp(-(x-xo).^2 / (2*sigma^2));

vecscale = 3e+2;

if(0)
  % plot this as a check
  figure(99)
  clf

  plot(x,y,'bo');
  hold on
  plot(x,yfit,'r-');
  xlabel('x')
  ylabel('y')
  axis([min(x(:)) max(x(:)) min([min(y(:)) 0]) max(y(:))])

  drawnow
end

% compute the error between the fitted and actual fields
err = abs([y(:)-yfit(:)]);