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

#*****************************************************************************80
#
## SHI_VALUES returns some values of the hyperbolic sine integral function.
#
#  Discussion:
#
#    SHI(X) = integral ( 0 <= T <= X ) sinh ( T ) / T dt
#
#    In Mathematica, the function can be evaluated by:
#
#      SinhIntegral[x]
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    20 February 2015
#
#  Author:
#
#    John Burkardt
#
#  Reference:
#
#    Milton Abramowitz, Irene Stegun,
#    Handbook of Mathematical Functions,
#    National Bureau of Standards, 1964,
#    ISBN: 0-486-61272-4,
#    LC: QA47.A34.
#
#    Stephen Wolfram,
#    The Mathematica Book,
#    Fourth Edition,
#    Cambridge University Press, 1999,
#    ISBN: 0-521-64314-7,
#    LC: QA76.95.W65.
#
#  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 F, the value of the function.
#
  import numpy as np

  n_max = 16

  f_vec = np.array ( ( \
    0.5069967498196672, \
    0.6121303965633808, \
    0.7193380189288998, \
    0.8289965633789345, \
    0.9414978265114335, \
    1.057250875375729, \
    1.300250361022057, \
    1.561713388361002, \
    1.845814141358504, \
    2.157290343425901, \
    2.501567433354976, \
    3.549340406224435, \
    4.973440475859807, \
    6.966162067504942, \
    9.817326911233034, \
    13.96788504934715  ))

  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
    f = 0.0
  else:
    x = x_vec[n_data]
    f = f_vec[n_data]
    n_data = n_data + 1

  return n_data, x, f

def shi_values_test ( ):

#*****************************************************************************80
#
## SHI_VALUES_TEST demonstrates the use of SHI_VALUES.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    20 February 2015
#
#  Author:
#
#    John Burkardt
#
  import platform

  print ( '' )
  print ( 'SHI_VALUES_TEST:' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  SHI_VALUES stores values of the SHI function.' )
  print ( '' )
  print ( '      X         SHI(X)' )
  print ( '' )

  n_data = 0

  while ( True ):

    n_data, x, f = shi_values ( n_data )

    if ( n_data == 0 ):
      break

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

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