function disk01_integrands_test03 ( )

%*****************************************************************************80
%
%% disk01_integrands_test03(): integral of exp(x) in the unit disk.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    19 April 2019
%
%  Author:
%
%    John Burkardt
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'disk01_integrands_test03():\n' );
  fprintf ( 1, '  Use a simple Monte Carlo approach to estimate the\n' );
  fprintf ( 1, '  integral of exp(X) over the disk of radius 1\n' );
  fprintf ( 1, '  centered at the origin.\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '           N       Exact Approximate   Error\n' );
  fprintf ( 1, '\n' );

  n = 1;
  for n_log2 = 0 : 20
    xy = disk_unit_sample ( n );
    f = p03_f ( n, xy );
    q = disk_unit_area ( ) * sum ( f ) / n;
    t = p03_exact ( );
    fprintf ( 1, '  %10d  %10.4f  %10.4f  %10.4e\n', n, t, q, abs ( t - q ) );
    n = n * 2;
  end

  return
end
