Two dimensional weight function for curve fitting

Hi! I'm fitting a matrix with a normal distribution using curve fitting toolbox. I want to add a weight function. Unfortunatly, I have found manuals only for 1-d weight function. I have a 2xN array with weight for X an Y (wts)

   opts=fitoptions('Weights',wts);
    gauss2 = fittype( @(a1, sigmax, sigmay, x0,y0, x, y) a1*exp(-(x-x0).^2/(2*sigmax^2)-(y-y0).^2/(2*sigmay^2)),...
        'independent', {'x', 'y'},'dependent', 'z' );
   wsf = fit([X,Y],double(Z),gauss2,opts);

And I get an error

Error using curvefit.basefitoptions/set

Matrix must be column or row vector.

Any ideas how to make a two dimensional weight function for curve fitting?