#! /usr/bin/env python
#
def circle01_sample ( n, seed ):

#*****************************************************************************80
#
## CIRCLE01_SAMPLE samples points on the circumference of the unit circle in 2D.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license. 
#
#  Modified:
#
#    21 June 2015
#
#  Author:
#
#    John Burkardt
#
#  Reference:
#
#    Russell Cheng,
#    Random Variate Generation,
#    in Handbook of Simulation,
#    edited by Jerry Banks,
#    Wiley, 1998, pages 168.
#
#    Reuven Rubinstein,
#    Monte Carlo Optimization, Simulation, and Sensitivity 
#    of Queueing Networks,
#    Krieger, 1992,
#    ISBN: 0894647644,
#    LC: QA298.R79.
#
#  Parameters:
#
#    Input, integer N, the number of points.
#
#    Input/output, integer SEED, a seed for the random 
#    number generator.
#
#    Output, real X(2,N), the points.
#
  import numpy as np
  from r8vec_uniform_01 import r8vec_uniform_01

  r = 1.0
  c = np.zeros ( 2 )

  theta, seed = r8vec_uniform_01 ( n, seed )

  x = np.zeros ( [ 2, n ] )

  for j in range ( 0, n ):
    x[0,j] = c[0] + r * np.cos ( 2.0 * np.pi * theta[j] )
    x[1,j] = c[1] + r * np.sin ( 2.0 * np.pi * theta[j] )

  return x, seed

def circle01_sample_test ( ):

#*****************************************************************************80
#
## CIRCLE01_SAMPLE_TEST tests CIRCLE01_SAMPLE.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    21 June 2015
#
#  Author:
#
#    John Burkardt
#
  import platform
  from r8mat_transpose_print import r8mat_transpose_print

  print ( '' )
  print ( 'CIRCLE01_SAMPLE_TEST' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  CIRCLE01_SAMPLE samples the unit circle.' )

  n = 10
  seed = 123456789

  x, seed = circle01_sample ( n, seed )

  r8mat_transpose_print ( 2, n, x, '  Sample points in the unit circle.' )
#
#  Terminate.
#
  print ( '' )
  print ( 'CIRCLE01_SAMPLE_TEST' )
  print ( '  Normal end of execution.' )
  return

if ( __name__ == '__main__' ):
  from timestamp import timestamp
  timestamp ( )
  circle01_sample_test ( )
  timestamp ( )