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

#*****************************************************************************80
#
## CIN_VALUES returns some values of the alternate cosine integral function.
#
#  Discussion:
#
#    The alternate cosine integral is defined by
#
#      CIN(X) = gamma + log(X) + integral ( 0 <= T <= X ) ( cos ( T ) - 1 ) / T  dT
#
#    In Mathematica, the function can be evaluated by:
#
#      EulerGamma + Log[x] - CosIntegral[x]
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    28 January 2015
#
#  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 = 16

  fx_vec = np.array ( ( \
     0.6185256314820045E-01, \
     0.8866074809482194E-01, \
     0.1200260139539026E+00, \
     0.1557934976348559E+00, \
     0.1957873187759337E+00, \
     0.2398117420005647E+00, \
     0.3390780388012470E+00, \
     0.4516813164280685E+00, \
     0.5754867772153906E+00, \
     0.7081912003853150E+00, \
     0.8473820166866132E+00, \
     0.1207635200410304E+01, \
     0.1556198167561642E+01, \
     0.1862107181909382E+01, \
     0.2104491723908354E+01, \
     0.2274784183779546E+01 ) )

  x_vec = np.array ( ( \
     0.5E+00, \
     0.6E+00, \
     0.7E+00, \
     0.8E+00, \
     0.9E+00, \
     1.0E+00, \
     1.2E+00, \
     1.4E+00, \
     1.6E+00, \
     1.8E+00, \
     2.0E+00, \
     2.5E+00, \
     3.0E+00, \
     3.5E+00, \
     4.0E+00, \
     4.5E+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 cin_values_test ( ):

#*****************************************************************************80
#
## CIN_VALUES_TEST demonstrates the use of CIN_VALUES.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    28 January 2015
#
#  Author:
#
#    John Burkardt
#
  import platform

  print ( '' )
  print ( 'CIN_VALUES_TEST:' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  CIN_VALUES stores values of the alternate cosine integral function.' )
  print ( '' )
  print ( '      X         CIN(X)' )
  print ( '' )

  n_data = 0

  while ( True ):

    n_data, x, fx = cin_values ( n_data )

    if ( n_data == 0 ):
      break

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

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