% Jacobian of the state transition function for the UNGM-model.%% Copyright (C) 2007 Jouni Hartikainen%% This software is distributed under the GNU General Public % Licence (version 2 or later); please refer to the file % Licence.txt, included with the software, for details.function df = ungm_df_dx(x,param)df = 0.5+25*(1-x.^2)./((1+x.^2).^2);