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

%*****************************************************************************80
%
%% GOODWIN_VALUES returns some values of the Goodwin and Staton function.
%
%  Discussion:
%
%    The function is defined by:
%
%      GOODWIN(x) = Integral ( 0 <= t < infinity ) exp ( -t^2 ) / ( t + x ) dt
%
%    The data was reported by McLeod.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    16 September 2004
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    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.
%
%  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 X, the argument of the function.
%
%    Output, real FX, the value of the function.
%
  n_max = 20;

  fx_vec = [ ...
      0.59531540040441651584E+01, ...
      0.45769601268624494109E+01, ...
      0.32288921331902217638E+01, ...
      0.19746110873568719362E+01, ...
      0.96356046208697728563E+00, ...
      0.60513365250334458174E+00, ...
      0.51305506459532198016E+00, ...
      0.44598602820946133091E+00, ...
      0.37344458206879749357E+00, ...
      0.35433592884953063055E+00, ...
      0.33712156518881920994E+00, ...
      0.29436170729362979176E+00, ...
      0.25193499644897222840E+00, ...
      0.22028778222123939276E+00, ...
      0.19575258237698917033E+00, ...
      0.17616303166670699424E+00, ...
      0.16015469479664778673E+00, ...
      0.14096116876193391066E+00, ...
      0.13554987191049066274E+00, ...
      0.11751605060085098084E+00 ];

  x_vec = [ ...
      0.0019531250E+00, ...
      0.0078125000E+00, ...
      0.0312500000E+00, ...
      0.1250000000E+00, ...
      0.5000000000E+00, ...
      1.0000000000E+00, ...
      1.2500000000E+00, ...
      1.5000000000E+00, ...
      1.8750000000E+00, ...
      2.0000000000E+00, ...
      2.1250000000E+00, ...
      2.5000000000E+00, ...
      3.0000000000E+00, ...
      3.5000000000E+00, ...
      4.0000000000E+00, ...
      4.5000000000E+00, ...
      5.0000000000E+00, ...
      5.7500000000E+00, ...
      6.0000000000E+00, ...
      7.0000000000E+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
