function kdv_etdrk4_test ( )

%*****************************************************************************80
%
%% kdv_etdrk4_test() tests kdv_etdrk4().
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    13 April 2020
%
%  Author:
%
%    Lloyd Trefethen.
%    Modification by John Burkardt
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'kdv_etdrk4_test():\n' );
  fprintf ( 1, '  kdv_etdrk4() solves the Korteweg-deVries equation\n' );
  fprintf ( 1, '  using the etdrk4 method.\n' );

  nx = 256;
  [ xx, tt, uu ] = kdv_etdrk4 ( nx );
%
%  Display the results.
%
  clf ( );
  surf ( xx, tt, uu, 'edgecolor', 'none' );
  title ( 'Korteweg-deVries equation solved by ETD RK4' );
  xlabel ( '<-- x -->' );
  ylabel ( '<-- t -->' );
  grid ( 'off' );
  pbaspect ( [ 1.0, 1.0, 0.13 ] );

  filename = 'kdv_etdrk4_test.png';
  print ( '-dpng', filename );
  fprintf ( 1, '  Graphics saved as "%s"\n', filename );

  return
end

