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

#*****************************************************************************80
#
## GAMMA_INC_TRICOMI_VALUES: values of Tricomi's incomplete Gamma function.
#
#  Discussion:
#
#    Tricomi's incomplete Gamma function is defined as:
#
#      1/Gamma(A) * 1/X^A * Integral ( 0 <= T <= X ) T^(A-1) * exp(-T) dT.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    14 February 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 A, the parameter of the function.
#
#    Output, real X, the argument of the function.
#
#    Output, real F, the value of the function.
#
  import numpy as np

  n_max = 20

  a_vec = np.array ( ( \
     0.10E+00, \
     0.10E+00, \
     0.10E+00, \
     0.50E+00, \
     0.50E+00, \
     0.50E+00, \
     0.10E+01, \
     0.10E+01, \
     0.10E+01, \
     0.11E+01, \
     0.11E+01, \
     0.11E+01, \
     0.20E+01, \
     0.20E+01, \
     0.20E+01, \
     0.60E+01, \
     0.60E+01, \
     0.11E+02, \
     0.26E+02, \
     0.41E+02  ))

  f_vec = np.array ( ( \
    1.048292641463504E+00, \
    1.024577737369574E+00, \
    0.9493712443185374E+00, \
    1.100793230316492E+00, \
    0.8998911979655218E+00, \
    0.5301656062431039E+00, \
    0.9516258196404043E+00, \
    0.6321205588285577E+00, \
    0.1986524106001829E+00, \
    0.9071784510537487E+00, \
    0.5891809618706485E+00, \
    0.1688269752193589E+00, \
    0.4527034271637121E+00, \
    0.1965220442795224E+00, \
    0.02025928457705232E+00, \
    0.0001721181724479739E+00, \
    3.280858070850586E-07, \
    5.244396471821590E-14, \
    2.013462926183376E-37, \
    1.230623887499875E-68 ))

  x_vec = np.array ( ( \
     0.30E-01, \
     0.30E+00, \
     0.15E+01, \
     0.75E-01, \
     0.75E+00, \
     0.35E+01, \
     0.10E+00, \
     0.10E+01, \
     0.50E+01, \
     0.10E+00, \
     0.10E+01, \
     0.50E+01, \
     0.15E+00, \
     0.15E+01, \
     0.70E+01, \
     0.25E+01, \
     0.12E+02, \
     0.16E+02, \
     0.25E+02, \
     0.45E+02 ))

  if ( n_data < 0 ):
    n_data = 0

  if ( n_max <= n_data ):
    n_data = 0
    a = 0.0
    x = 0.0
    f = 0.0
  else:
    a = a_vec[n_data]
    x = x_vec[n_data]
    f = f_vec[n_data]
    n_data = n_data + 1

  return n_data, a, x, f

def gamma_inc_tricomi_values_test ( ):

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

  print ( '' )
  print ( 'GAMMA_INC_TRICOMI_VALUES_TEST:' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  GAMMA_INC_TRICOMI_VALUES stores values of an incomplete Gamma function.' )
  print ( '' )
  print ( '      A         X        F(A,X)' )
  print ( '' )

  n_data = 0

  while ( True ):

    n_data, a, x, f = gamma_inc_tricomi_values ( n_data )

    if ( n_data == 0 ):
      break

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

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