function [ n_data, a, b, x, fx ] =  hypergeometric_u_values ( n_data )

%*****************************************************************************80
%
%% HYPERGEOMETRIC_U_VALUES: some values of the hypergeometric function U(a,b,x).
%
%  Discussion:
%
%    In Mathematica, the function can be evaluated by:
%
%      fx = HypergeometricU [ a, b, x ]
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license. 
%
%  Modified:
%
%    02 October 2011
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Milton Abramowitz, Irene Stegun,
%    Handbook of Mathematical Functions,
%    National Bureau of Standards, 1964,
%    ISBN: 0-486-61272-4,
%    LC: QA47.A34.
%
%    Stephen Wolfram,
%    The Mathematica Book,
%    Fourth Edition,
%    Cambridge University Press, 1999,
%    ISBN: 0-521-64314-7,
%    LC: QA76.95.W65.
%
%    Daniel Zwillinger, editor,
%    CRC Standard Mathematical Tables and Formulae,
%    30th Edition,
%    CRC Press, 1996,
%    ISBN: 0-8493-2479-3,
%    LC: QA47.M315.
%
%  Parameters:
%
%    Input/output, integer N_DATA.  The user sets N_DATA to 0 
%    before the first call.  On each call, the routine increments N_DATA by 1,
%    and returns the corresponding data; when there is no more data, the
%    output value of N_DATA will be 0 again.
%
%    Output, real A, B, X, the parameters.
%
%    Output, real FX, the value of the function.
%
  n_max = 24;

  a_vec = [ ...
    -2.500, ...
    -0.500, ...
     0.500, ...
     2.500, ...
    -2.500, ...
    -0.500, ...
     0.500, ...
     2.500, ...
    -2.500, ...
    -0.500, ...
     0.500, ...
     2.500, ...
     0.825, ...
     1.100, ...
     1.650, ...
     3.300, ...
     0.825, ...
     1.100, ...
     1.650, ...
     3.300, ...
     0.825, ...
     1.100, ...
     1.650,... 
     3.300 ];
  b_vec = [ ...
     3.3, ...
     1.1, ...
     1.1, ...
     3.3, ...
     3.3, ...
     1.1, ...
     1.1, ...
     3.3, ...
     3.3, ...
     1.1, ...
     1.1, ...
     3.3, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7, ...
     6.7 ];
  fx_vec = [ ...
         -68.693628728078601389E+00, ...
          -0.0029710551374761070801E+00, ...
           1.5008631742177797301E+00, ...
          20.614688244200596134E+00, ...
           7.4563815469305551938E+00, ...
           1.0155793767749293733E+00, ...
           0.73446538936622668912E+00, ...
           0.28046404941879399225E+00, ...
           3.4508153741446547607E+00, ...
           1.5156637368753063495E+00, ...
           0.56042118587934993510E+00, ...
           0.064897147735134223341E+00, ...
      223432.02356977463356E+00, ...
      263079.25980740811495E+00, ...
      269802.90319351274132E+00, ...
       82809.311335606553425E+00, ...
          26.465684783131844524E+00, ...
          28.093506172516056560E+00, ...
          23.889164624518872504E+00, ...
           4.5338847857070388229E+00, ...
           3.0224469362694842535E+00, ...
           2.8040650913713359934E+00, ...
           1.9262578111480172682E+00, ...
           0.23020518115860909098E+00 ];
  x_vec = [ ...
     0.25, ...
     0.25, ...
     0.25, ...
     0.25, ...
     1.55, ...
     1.55, ...
     1.55, ...
     1.55, ...
     2.85, ...
     2.85, ...
     2.85, ...
     2.85, ...
     0.25, ...
     0.25, ...
     0.25, ...
     0.25, ...
     1.55, ...
     1.55, ...
     1.55, ...
     1.55, ...
     2.85, ...
     2.85, ...
     2.85, ...
     2.85 ];

  if ( n_data < 0 )
    n_data = 0;
  end
 
  n_data = n_data + 1;

  if ( n_max < n_data )
    n_data = 0;
    a = 0.0;
    b = 0.0;
    x = 0.0;
    fx = 0.0;
  else
    a = a_vec(n_data);
    b = b_vec(n_data);
    x = x_vec(n_data);
    fx = fx_vec(n_data);
  end

  return
end
