#! /usr/bin/env python
#
def r8_pi ( ):

#*****************************************************************************80
#
## R8_PI returns the value of pi as an R8.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    04 June 2013
#
#  Author:
#
#    John Burkardt
#
#  Parameters:
#
#    Output, real VALUE, the value of pi.
#
  value = 3.141592653589793

  return value

def r8_pi_test ( ):

#*****************************************************************************80
#
## R8_PI_TEST tests R8_PI.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    26 July 2014
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  import platform

  print ( '' )
  print ( 'R8_PI_TEST' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  R8_PI returns the value of PI.' )
  print ( '' )
  v1 = r8_pi ( )
  print ( '  R8_PI       =       %24.16f' % ( v1 ) )
  v2 = 4.0 * np.arctan ( 1.0 )
  print ( '  4 * Atan(1) = %24.16f' % ( v2 ) )
  v3 = np.pi
  print ( '  np.pi       =       %24.16f' % ( v3 ) )
#
#  Terminate.
#
  print ( '' )
  print ( 'R8_PI_TEST' )
  print ( '  Normal end of execution.' )
  return

if ( __name__ == '__main__' ):
  from timestamp import timestamp
  timestamp ( )
  r8_pi_test ( )
  timestamp ( )