function [ n_data, x, fx ] = airy_ai_int_values ( n_data )

%*****************************************************************************80
%
%% airy_ai_int_values() returns some values of the integral of the Airy function.
%
%  Discussion:
%
%    The function is defined by:
%
%      AIRY_AI_INT(x) = Integral ( 0 <= t <= x ) Ai(t) dt
%
%    The data was reported by McLeod.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    15 September 2004
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Milton Abramowitz and Irene Stegun,
%    Handbook of Mathematical Functions,
%    US Department of Commerce, 1964.
%
%    Allan McLeod,
%    Algorithm 757, MISCFUN: A software package to compute uncommon
%      special functions,
%    ACM Transactions on Mathematical Software,
%    Volume 22, Number 3, September 1996, pages 288-301.
%
%  Input:
%
%    integer N_DATA.  The user sets N_DATA to 0 before the first call.  
%    Thereafter, it should simply be the value returned by the previous call.
%
%  Output:
%
%    integer N_DATA.  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.
%
%    real X, the argument of the function.
%
%    real FX, the value of the function.
%
  n_max = 20;

  fx_vec = [ ...
     -0.75228838916610124300E+00, ...
     -0.57348350185854889466E+00, ...
     -0.76569840313421291743E+00, ...
     -0.65181015505382467421E+00, ...
     -0.55881974894471876922E+00, ...
     -0.56902352870716815309E+00, ...
     -0.47800749642926168100E+00, ...
     -0.46567398346706861416E+00, ...
     -0.96783140945618013679E-01, ...
     -0.34683049857035607494E-03, ...
      0.34658366917927930790E-03, ...
      0.27657581846051227124E-02, ...
      0.14595330491185717833E+00, ...
      0.23631734191710977960E+00, ...
      0.33289264538612212697E+00, ...
      0.33318759129779422976E+00, ...
      0.33332945170523851439E+00, ...
      0.33333331724248357420E+00, ...
      0.33333333329916901594E+00, ...
      0.33333333333329380187E+00 ];

  x_vec = [ ...
     -12.0000000000E+00, ...
     -11.0000000000E+00, ...
     -10.0000000000E+00, ...
      -9.5000000000E+00, ...
      -9.0000000000E+00, ...
      -6.5000000000E+00, ...
      -4.0000000000E+00, ...
      -1.0000000000E+00, ...
      -0.2500000000E+00, ...
      -0.0009765625E+00, ...
       0.0009765625E+00, ...
       0.0078125000E+00, ...
       0.5000000000E+00, ...
       1.0000000000E+00, ...
       4.0000000000E+00, ...
       4.5000000000E+00, ...
       6.0000000000E+00, ...
       8.0000000000E+00, ...
      10.0000000000E+00, ...
      12.0000000000E+00 ];  

  if ( n_data < 0 )
    n_data = 0;
  end

  n_data = n_data + 1;

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

  return
end
