function_library.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
 
# 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)')
 
asec = Function(name='asec', arguments=('z', ), expression='cmath.acos(1./z)')
 
csc = Function(name='csc', arguments=('z', ), expression='1./cmath.sin(z)')
 
acsc = Function(name='acsc', arguments=('z', ), expression='cmath.asin(1./z)')
 
cot = Function(name='cot', arguments=('z', ), expression='1./cmath.tan(z)')
 
# 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))')