function_library.py

# This file is part of the UFO.
#
# This file contains definitions for functions that
# are extensions of the cmath library, and correspond
# either to functions that are in cmath, but inconvenient
# to access from there (e.g. z.conjugate()),
# or functions that are simply not defined.
#
#
 
__date__ = "22 July 2010"
__author__ = "claude.duhr@durham.ac.uk"
 
import cmath
from object_library import all_functions, Function
 
#
# shortcuts for functions from cmath
#
 
complexconjugate = Function(name='complexconjugate',
                            arguments=('z',),
                            expression='z.conjugate()')
 
 
re = Function(name='re',
              arguments=('z',),
              expression='z.real')
 
im = Function(name='im',
              arguments=('z',),
              expression='z.imag')
 
# New functions (trigonometric)
 
sec = Function(name='sec',
               arguments=('z',),
               expression='1./cmath.cos(z.real)')
 
asec = Function(name='asec',
                arguments=('z',),
                expression='cmath.acos(1./(z.real))')
 
csc = Function(name='csc',
               arguments=('z',),
               expression='1./cmath.sin(z.real)')
 
acsc = Function(name='acsc',
                arguments=('z',),
                expression='cmath.asin(1./(z.real))')
 
cot = Function(name='cot',
               arguments=('z',),
               expression='1./cmath.tan(z.real)')
 
# Heaviside theta function
 
theta_function = Function(name='theta_function',
                          arguments=('x', 'y', 'z'),
                          expression='y if x else z')
 
# Auxiliary functions for NLO
 
cond = Function(name='cond',
                arguments=('condition', 'ExprTrue', 'ExprFalse'),
                expression='(ExprTrue if condition==0.0 else ExprFalse)')
 
reglog = Function(name='reglog',
                  arguments=('z'),
                  expression='(0.0 if z==0.0 else cmath.log(z.real))')