function value = humps_deriv ( x, y )

%*****************************************************************************80
%
%% humps_deriv() evaluates the derivative of the humps function.
%
%  Discussion:
%
%    This version of the function includes a "y" argument that is only
%    a placeholder expected by ODE solvers.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    25 July 2019
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real X, Y: the arguments for the humps derivative function.
%
%  Output:
%
%    real VALUE, the right hand side of the humps ODE.
%
  value = - 1.0 ./ ( ( x - 0.3 ).^2 + 0.01 ).^2 ...
          .* 2.0 .* ( x - 0.3 ) ...
          - 1.0 ./ ( ( x - 0.9 ).^2 + 0.04 ).^2 ...
          .* 2.0 .* ( x - 0.9 );
  return
end
