function dn = jacobi_dn ( u, m )

%*****************************************************************************80
%
%% JACOBI_DN evaluates the Jacobi elliptic function DN(U,M).
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    25 June 2018
%
%  Author:
%
%    Original ALGOL version by Roland Bulirsch.
%    MATLAB version by John Burkardt
%
%  Reference:
%
%    Roland Bulirsch,
%    Numerical calculation of elliptic integrals and elliptic functions,
%    Numerische Mathematik,
%    Volume 7, Number 1, 1965, pages 78-90.
%
%  Parameters:
%
%    Input, real U, M, the arguments.
%
%    Output, real DN, the function value.
%
  [ sn, cn, dn ] = sncndn ( u, m );

  return
end