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

%*****************************************************************************80
%
%% BESSEL_IN_VALUES returns some values of the In Bessel function.
%
%  Discussion:
%
%    The modified Bessel functions In(Z) and Kn(Z) are solutions of
%    the differential equation
%
%      Z^2 W'' + Z * W' - ( Z^2 + N^2 ) * W = 0.
%
%    In Mathematica, the function can be evaluated by:
%
%      BesselI[n,x]
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    29 September 2004
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Milton Abramowitz and Irene Stegun,
%    Handbook of Mathematical Functions,
%    US Department of Commerce, 1964.
%
%    Stephen Wolfram,
%    The Mathematica Book,
%    Fourth Edition,
%    Wolfram Media / Cambridge University Press, 1999.
%
%  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, integer 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 = [ ...
     0.5016687513894678E-02, ...
     0.1357476697670383E+00, ...
     0.6889484476987382E+00, ...
     0.1276466147819164E+01, ...
     0.2245212440929951E+01, ...
     0.1750561496662424E+02, ...
     0.2281518967726004E+04, ...
     0.3931278522104076E+08, ...
     0.2216842492433190E-01, ...
     0.2127399592398527E+00, ...
     0.1033115016915114E+02, ...
     0.1758380716610853E+04, ...
     0.2677764138883941E+21, ...
     0.2714631559569719E-03, ...
     0.9825679323131702E-02, ...
     0.2157974547322546E+01, ...
     0.7771882864032600E+03, ...
     0.2278548307911282E+21, ...
     0.2752948039836874E-09, ...
     0.3016963879350684E-06, ...
     0.4580044419176051E-02, ...
     0.2189170616372337E+02, ...
     0.1071597159477637E+21, ...
     0.3966835985819020E-24, ...
     0.4310560576109548E-18, ...
     0.5024239357971806E-10, ...
     0.1250799735644948E-03, ...
     0.5442008402752998E+19 ];

  nu_vec = [ ...
     2,  2,  2,  2, ...
     2,  2,  2,  2, ...
     3,  3,  3,  3, ...
     3,  5,  5,  5, ...
     5,  5, 10, 10, ...
    10, 10, 10, 20, ...
    20, 20, 20, 20 ];

  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;
    x = 0.0;
    fx = 0.0;
  else
    nu = nu_vec(n_data);
    x = x_vec(n_data);
    fx = fx_vec(n_data);
  end

  return
end
