function [ n_data, nu, x, fx ] = bessel_yx_values ( n_data )

%% BESSEL_YX_VALUES returns some values of the Yx Bessel function.
%
%  Discussion:
%
%    This set of data considers the less common case in which the
%    index of the Bessel function Yn is actually not an integer.
%    We may suggest this case by occasionally replacing the symbol
%    "Yn" by "Yx".
%
%    In Mathematica, the function can be evaluated by:
%
%      BesselY[n,x]
%
%  Modified:
%
%    01 April 2007
%
%  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.
%
%  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 NU, the order of the function.
%
%    Output, real X, the argument of the function.
%
%    Output, real FX, the value of the function.
%
  n_max = 28;

  fx_vec = [ ...
       -1.748560416961876E+00, ...
       -0.4310988680183761E+00, ...
        0.2347857104062485E+00, ...
        0.4042783022390569E+00, ...
        0.4560488207946332E+00, ...
       -0.1012177091851084E+00, ...
        0.2117088663313982E+00, ...
       -0.07280690478506185E+00, ...
       -1.102495575160179E+00, ...
       -0.3956232813587035E+00, ...
        0.3219244429611401E+00, ...
        0.1584346223881903E+00, ...
        0.02742813676191382E+00, ...
       -2.876387857462161E+00, ...
       -0.8282206324443037E+00, ...
        0.2943723749617925E+00, ...
       -0.1641784796149411E+00, ...
        0.1105304445562544E+00, ...
       -0.9319659251969881E+00, ...
       -0.2609445010948933E+00, ...
        0.2492796362185881E+00, ...
        0.2174410301416733E+00, ...
       -0.01578576650557229E+00, ...
       -4.023453301501028E+00, ...
       -0.9588998694752389E+00, ...
        0.2264260361047367E+00, ...
       -0.2193617736566760E+00, ...
        0.09413988344515077E+00 ];
  nu_vec = [ ...
    0.50E+00, ...
    0.50E+00, ...
    0.50E+00, ...
    0.50E+00, ...
    0.50E+00, ...
    0.50E+00, ...
    0.50E+00, ...
    0.50E+00, ...
    1.50E+00, ...
    1.50E+00, ...
    1.50E+00, ...
    1.50E+00, ...
    1.50E+00, ...
    2.50E+00, ...
    2.50E+00, ...
    2.50E+00, ...
    2.50E+00, ...
    2.50E+00, ...
    1.25E+00, ...
    1.25E+00, ...
    1.25E+00, ...
    1.25E+00, ...
    1.25E+00, ...
    2.75E+00, ...
    2.75E+00, ...
    2.75E+00, ...
    2.75E+00, ...
    2.75E+00 ];

  x_vec = [ ...
      0.2E+00, ...
      1.0E+00, ...
      2.0E+00, ...
      2.5E+00, ...
      3.0E+00, ...
      5.0E+00, ...
     10.0E+00, ...
     20.0E+00, ...
      1.0E+00, ...
      2.0E+00, ...
      5.0E+00, ...
     10.0E+00, ...
     50.0E+00, ...
      1.0E+00, ...
      2.0E+00, ...
      5.0E+00, ...
     10.0E+00, ...
     50.0E+00, ...
      1.0E+00, ...
      2.0E+00, ...
      5.0E+00, ...
     10.0E+00, ...
     50.0E+00, ...
      1.0E+00, ...
      2.0E+00, ...
      5.0E+00, ...
     10.0E+00, ...
     50.0E+00 ];

  if ( n_data < 0 )
    n_data = 0;
  end

  n_data = n_data + 1;

  if ( n_max < n_data )
    n_data = 0;
    nu = 0.0;
    x = 0.0;
    fx = 0.0;
  else
    nu = nu_vec(n_data);
    x = x_vec(n_data);
    fx = fx_vec(n_data);
  end