function [ n_data, beta, x, f ] = exponential_pdf_values ( n_data )

%*****************************************************************************80
%
%% EXPONENTIAL_PDF_VALUES returns some values of the Exponential PDF.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    29 July 2015
%
%  Author:
%
%    John Burkardt
%
%  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 BETA, the parameter of the distribution.
%
%    Output, real X, the argument of the function.
%
%    Output, real FX, the value of the function.
%
  n_max = 10;

  beta_vec = [ ...
         1.092091484911879, ...
         4.147546169663503, ...
         2.076535407379806, ...
         1.287888961910225, ...
        0.2191449888955355, ...
        0.3086361453280091, ...
         2.006531407488083, ...
         3.986434770531281, ...
         4.487520304498656, ...
         0.472723751058401 ];

  f_vec = [ ...
     0.0001446999730194618, ...
       0.06289850821824726, ...
        0.3663607831924032, ...
        0.3542787877169571, ...
     1.472582451176006e-12, ...
     1.829637907028298e-06, ...
       0.01173398427218792, ...
                       0.0, ...
        0.1034724689882351, ...
          1.95394780436833 ];

  x_vec = [ ...
         9.558807522740191, ...
         5.573123971945631, ...
        0.5677992226519164, ...
         1.010563614677953, ...
         6.303053694254367, ...
         4.440343499102481, ...
         7.522202212856243, ...
      -0.08143245130010748, ...
         3.442598613603521, ...
       0.03753060499296568 ];

  if ( n_data < 0 )
    n_data = 0;
  end

  n_data = n_data + 1;

  if ( n_max < n_data )
    n_data = 0;
    beta = 0.0;
    x = 0.0;
    f = 0.0;
  else
    beta = beta_vec(n_data);
    x = x_vec(n_data);
    f = f_vec(n_data);
  end

  return
end
