#! /usr/bin/env python
#
def gamma_log_values ( n_data ):

#*****************************************************************************80
#
## GAMMA_LOG_VALUES returns some values of the Log Gamma function.
#
#  Discussion:
#
#    In Mathematica, the function can be evaluated by:
#
#      Log[Gamma[x]]
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    23 November 2014
#
#  Author:
#
#    John Burkardt
#
#  Reference:
#
#    Milton Abramowitz and Irene Stegun,
#    Handbook of Mathematical Functions,
#    US Department of Commerce, 1964.
#
#    Stephen Wolfram,
#    The Mathematica Book,
#    Fourth Edition,
#    Wolfram Media / Cambridge University Press, 1999.
#
#  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 X, the argument of the function.
#
#    Output, real FX, the value of the function.
#
  import numpy as np

  n_max = 20

  fx_vec = np.array ( ( \
      0.1524063822430784E+01, \
      0.7966778177017837E+00, \
      0.3982338580692348E+00, \
      0.1520596783998375E+00, \
      0.0000000000000000E+00, \
     -0.4987244125983972E-01, \
     -0.8537409000331584E-01, \
     -0.1081748095078604E+00, \
     -0.1196129141723712E+00, \
     -0.1207822376352452E+00, \
     -0.1125917656967557E+00, \
     -0.9580769740706586E-01, \
     -0.7108387291437216E-01, \
     -0.3898427592308333E-01, \
     0.00000000000000000E+00, \
     0.69314718055994530E+00, \
     0.17917594692280550E+01, \
     0.12801827480081469E+02, \
     0.39339884187199494E+02, \
     0.71257038967168009E+02 ) )

  x_vec = np.array ( ( \
      0.20E+00, \
      0.40E+00, \
      0.60E+00, \
      0.80E+00, \
      1.00E+00, \
      1.10E+00, \
      1.20E+00, \
      1.30E+00, \
      1.40E+00, \
      1.50E+00, \
      1.60E+00, \
      1.70E+00, \
      1.80E+00, \
      1.90E+00, \
      2.00E+00, \
      3.00E+00, \
      4.00E+00, \
     10.00E+00, \
     20.00E+00, \
     30.00E+00 ) )

  if ( n_data < 0 ):
    n_data = 0

  if ( n_max <= n_data ):
    n_data = 0
    x = 0.0
    fx = 0.0
  else:
    x = x_vec[n_data]
    fx = fx_vec[n_data]
    n_data = n_data + 1

  return n_data, x, fx

def gamma_log_values_test ( ):

#*****************************************************************************80
#
## GAMMA_LOG_VALUE_TEST demonstrates the use of GAMMA_LOG_VALUES.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    02 February 2009
#
#  Author:
#
#    John Burkardt
#
  import platform

  print ( '' )
  print ( 'GAMMA_LOG_VALUES:' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  GAMMA_LOG_VALUES stores values of' )
  print ( '  the logarithm of the Gamma function.' )
  print ( '' )
  print ( '      X            GAMMA_LOG(X)' )
  print ( '' )

  n_data = 0

  while ( True ):

    n_data, x, fx = gamma_log_values ( n_data )

    if ( n_data == 0 ):
      break

    print ( '  %12f  %24.16f' % ( x, fx ) )
#
#  Terminate.
#
  print ( '' )
  print ( 'GAMMA_LOG_VALUES_TEST:' )
  print ( '  Normal end of execution.' )
  return

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