function lf_function_plot ( a, b, index, index2, filename )

%*****************************************************************************80
%
%% lf_function_plot() plots Laguerre functions Lf(n,alpha,x).
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    10 March 2012
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real A, B, the plotting range.
%
%    integer INDEX(*), the orders of 1 or more Laguerre functions.
%
%    integer INDEX2(*), the second "ALPHA" index.
%
%    string FILENAME, the name into which the graphics information is
%    to be stored.  Note that the PNG format will be used.
%
  mm = 501;
  x = linspace ( a, b, mm );
  x = x';
  index_num = length ( index );

  clf (  );
  hold ( 'on' );
  for i = 1 : index_num
    n = index(i);
    alpha = index2(i);
    y = lf_function ( mm, n, alpha, x );
    plot ( x, y(:,n+1), 'LineWidth', 2 );
  end
  grid ( 'on' );
  xlabel ( '<--- X --->' );
  ylabel ( '<---Lf(n,alpha,x) --->' );
  title ( 'Laguerre Functions Lf(n,alpha,x)' );
  hold ( 'off' );
  print ( '-dpng', filename )
  fprintf ( 1, '  Graphics saved as "%s"\n', filename );

  return
end
