def METHOD_NAME(cls, params, md, x=0, y=0, roiHalfSize=5):
    #generate grid to evaluate function on
    vs = md.voxelsize_nm
    X = vs.x*scipy.mgrid[(x - roiHalfSize):(x + roiHalfSize + 1)]
    Y = vs.y*scipy.mgrid[(x - roiHalfSize):(x + roiHalfSize + 1)]
    return f_gauss2d(params, X, Y)