function half_normal_sample_test ( )

%*****************************************************************************80
%
%% half_normal_sample_test() tests half_normal_sample().
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    15 April 2009
%
%  Author:
%
%    John Burkardt
%
  nsample = 1000;

  fprintf ( 1, '\n' );
  fprintf ( 1, 'HALF_NORMAL_SAMPLE_TEST():\n' );
  fprintf ( 1, '  HALF_NORMAL_MEAN() computes the Half Normal mean;\n' );
  fprintf ( 1, '  HALF_NORMAL_SAMPLE() samples the Half Normal distribution;\n' );
  fprintf ( 1, '  HALF_NORMAL_VARIANCE() computes the Half Normal variance.\n' );

  a = 0.0;
  b = 10.0;

  check = half_normal_check ( a, b );

  if ( ~ check );
    fprintf ( 1, '\n' );
    fprintf ( 1, 'HALF_NORMAL_SAMPLE_TEST(): Fatal error!\n' );
    fprintf ( 1, '  The parameters are not legal.\n' );
    return
  end

  xmean = half_normal_mean ( a, b );
  variance = half_normal_variance ( a, b );

  fprintf ( 1, '\n' );
  fprintf ( 1, '  PDF parameter A =             %14g\n', a );
  fprintf ( 1, '  PDF parameter B =             %14g\n', b );
  fprintf ( 1, '  PDF mean =                    %14g\n', xmean );
  fprintf ( 1, '  PDF variance =                %14g\n', variance );

  for i = 1 : nsample
    x(i) = half_normal_sample ( a, b );
  end

  xmean = mean ( x );
  variance = r8vec_variance ( nsample, x );
  xmax = max ( x );
  xmin = min ( x );

  fprintf ( 1, '\n' );
  fprintf ( 1, '  Sample size =     %6d\n', nsample );
  fprintf ( 1, '  Sample mean =     %14g\n', xmean );
  fprintf ( 1, '  Sample variance = %14g\n', variance );
  fprintf ( 1, '  Sample maximum =  %14g\n', xmax );
  fprintf ( 1, '  Sample minimum =  %14g\n', xmin );

  return
end
