object_library.py

 
 
import cmath
import re
 
 
class UFOError(Exception):
    """Exception raised if when inconsistencies are detected in the UFO model."""
    pass
 
 
class UFOBaseClass(object):
    """The class from which all FeynRules classes are derived."""
 
    require_args = []
 
    def __init__(self, *args, **options):
        assert(len(self.require_args) == len(args))
 
        for i, name in enumerate(self.require_args):
            setattr(self, name, args[i])
 
        for (option, value) in options.items():
            setattr(self, option, value)
 
    def get(self, name):
        return getattr(self, name)
 
    def set(self, name, value):
        setattr(self, name, value)
 
    def get_all(self):
        """Return a dictionary containing all the information of the object"""
        return self.__dict__
 
    def __str__(self):
        return self.name
 
    def nice_string(self):
        """ return string with the full information """
        return '\n'.join(['%s \t: %s' % (name, value) for name, value in self.__dict__.items()])
 
    def __repr__(self):
        replacements = [
            ('+', '__plus__'),
            ('-', '__minus__'),
            ('@', '__at__'),
            ('!', '__exclam__'),
            ('?', '__quest__'),
            ('*', '__star__'),
            ('~', '__tilde__')
        ]
        text = self.name
        for orig, sub in replacements:
            text = text.replace(orig, sub)
        return text
 
 
all_particles = []
 
 
class Particle(UFOBaseClass):
    """A standard Particle"""
 
    require_args = ['pdg_code', 'name', 'antiname', 'spin', 'color', 'mass', 'width', 'texname', 'antitexname', 'charge']
 
    require_args_all = [
        'pdg_code',
        'name',
        'antiname',
        'spin',
        'color',
        'mass',
        'width',
        'texname',
        'antitexname',
        'counterterm',
        'charge',
        'line',
        'propagating',
        'goldstoneboson',
        'propagator']
 
    def __init__(self, pdg_code, name, antiname, spin, color, mass, width, texname,
                 antitexname, charge, line=None, propagating=True, counterterm=None, goldstoneboson=False,
                 propagator=None, **options):
 
        args = (pdg_code, name, antiname, spin, color, mass, width, texname,
                antitexname, float(charge))
 
        UFOBaseClass.__init__(self, *args, **options)
 
        global all_particles
        all_particles.append(self)
 
        self.propagating = propagating
        self.goldstoneboson = goldstoneboson
 
        self.selfconjugate = (name == antiname)
        if not line:
            self.line = self.find_line_type()
        else:
            self.line = line
 
        if propagator:
            if isinstance(propagator, dict):
                self.propagator = propagator
            else:
                self.propagator = {0: propagator, 1: propagator}
 
    def find_line_type(self):
        """ find how we draw a line if not defined
        valid output: dashed/straight/wavy/curly/double/swavy/scurly
        """
 
        spin = self.spin
        color = self.color
 
        # use default
        if spin == 1:
            return 'dashed'
        elif spin == 2:
            if not self.selfconjugate:
                return 'straight'
            elif color == 1:
                return 'swavy'
            else:
                return 'scurly'
        elif spin == 3:
            if color == 1:
                return 'wavy'
 
            else:
                return 'curly'
        elif spin == 5:
            return 'double'
        elif spin == -1:
            return 'dotted'
        else:
            return 'dashed'  # not supported yet
 
    def anti(self):
        if self.selfconjugate:
            raise Exception('%s has no anti particle.' % self.name)
        outdic = {}
        for k, v in self.__dict__.iteritems():
            if k not in self.require_args_all:
                outdic[k] = -v
        if self.color in [1, 8]:
            newcolor = self.color
        else:
            newcolor = -self.color
 
        return Particle(-self.pdg_code, self.antiname, self.name, self.spin, newcolor, self.mass, self.width,
                        self.antitexname, self.texname, -self.charge, self.line, self.propagating, self.goldstoneboson, **outdic)
 
 
all_parameters = []
 
 
class Parameter(UFOBaseClass):
 
    require_args = ['name', 'nature', 'type', 'value', 'texname']
 
    def __init__(self, name, nature, type, value, texname, lhablock=None, lhacode=None):
 
        args = (name, nature, type, value, texname)
 
        UFOBaseClass.__init__(self, *args)
 
        args = (name, nature, type, value, texname)
 
        global all_parameters
        all_parameters.append(self)
 
        if (lhablock is None or lhacode is None) and nature == 'external':
            raise Exception('Need LHA information for external parameter "%s".' % name)
        self.lhablock = lhablock
        self.lhacode = lhacode
 
all_CTparameters = []
 
 
class CTParameter(UFOBaseClass):
 
    require_args = ['name', 'nature,', 'type', 'value', 'texname']
 
    def __init__(self, name, type, value, texname):
 
        args = (name, 'internal', type, value, texname)
 
        UFOBaseClass.__init__(self, *args)
 
        args = (name, 'internal', type, value, texname)
 
        self.nature = 'interal'
 
        global all_CTparameters
        all_CTparameters.append(self)
 
    def finite(self):
        try:
            return self.value[0]
        except KeyError:
            return 'ZERO'
 
    def pole(self, x):
        try:
            return self.value[-x]
        except KeyError:
            return 'ZERO'
 
all_vertices = []
 
 
class Vertex(UFOBaseClass):
 
    require_args = ['name', 'particles', 'color', 'lorentz', 'couplings']
 
    def __init__(self, name, particles, color, lorentz, couplings, **opt):
 
        args = (name, particles, color, lorentz, couplings)
 
        UFOBaseClass.__init__(self, *args, **opt)
 
        args = (particles, color, lorentz, couplings)
 
        global all_vertices
        all_vertices.append(self)
 
all_CTvertices = []
 
 
class CTVertex(UFOBaseClass):
 
    require_args = ['name', 'particles', 'color', 'lorentz', 'couplings', 'type', 'loop_particles']
 
    def __init__(self, name, particles, color, lorentz, couplings, type, loop_particles, **opt):
 
        args = (name, particles, color, lorentz, couplings, type, loop_particles)
 
        UFOBaseClass.__init__(self, *args, **opt)
 
        args = (particles, color, lorentz, couplings, type, loop_particles)
 
        global all_CTvertices
        all_CTvertices.append(self)
 
all_couplings = []
 
 
class Coupling(UFOBaseClass):
 
    require_args = ['name', 'value', 'order']
 
    require_args_all = ['name', 'value', 'order', 'loop_particles', 'counterterm']
 
    def __init__(self, name, value, order, **opt):
 
        args = (name, value, order)
        UFOBaseClass.__init__(self, *args, **opt)
        global all_couplings
        all_couplings.append(self)
 
    def value(self):
        return self.pole(0)
 
    def pole(self, x):
        """ the self.value attribute can be a dictionary directly specifying the Laurent serie using normal
        parameter or just a string which can possibly contain CTparameter defining the Laurent serie."""
 
        if isinstance(self.value, dict):
            if -x in self.value.keys():
                return self.value[-x]
            else:
                return 'ZERO'
 
        CTparam = None
        for param in all_CTparameters:
            pattern = re.compile(r"(?P<first>\A|\*|\+|\-|\()(?P<name>" + param.name + r")(?P<second>\Z|\*|\+|\-|\))")
            numberOfMatches = len(pattern.findall(self.value))
            if numberOfMatches == 1:
                if not CTparam:
                    CTparam = param
                else:
                    raise UFOError("UFO does not support yet more than one occurence of CTParameters in the couplings values.")
            elif numberOfMatches > 1:
                raise UFOError("UFO does not support yet more than one occurence of CTParameters in the couplings values.")
 
        if not CTparam:
            if x == 0:
                return self.value
            else:
                return 'ZERO'
        else:
            if CTparam.pole(x) == 'ZERO':
                return 'ZERO'
            else:
                def substitution(matchedObj):
                    return matchedObj.group('first') + "(" + CTparam.pole(x) + ")" + matchedObj.group('second')
                pattern = re.compile(r"(?P<first>\A|\*|\+|\-|\()(?P<name>" + CTparam.name + r")(?P<second>\Z|\*|\+|\-|\))")
                return pattern.sub(substitution, self.value)
 
all_lorentz = []
 
 
class Lorentz(UFOBaseClass):
 
    require_args = ['name', 'spins', 'structure']
 
    def __init__(self, name, spins, structure='external', **opt):
        args = (name, spins, structure)
        UFOBaseClass.__init__(self, *args, **opt)
 
        global all_lorentz
        all_lorentz.append(self)
 
 
all_functions = []
 
 
class Function(object):
 
    def __init__(self, name, arguments, expression):
 
        global all_functions
        all_functions.append(self)
 
        self.name = name
        self.arguments = arguments
        self.expr = expression
 
    def __call__(self, *opt):
 
        for i, arg in enumerate(self.arguments):
            exec('%s = %s' % (arg, opt[i]))
 
        return eval(self.expr)
 
all_orders = []
 
 
class CouplingOrder(object):
 
    def __init__(self, name, expansion_order, hierarchy, perturbative_expansion=0):
 
        global all_orders
        all_orders.append(self)
 
        self.name = name
        self.expansion_order = expansion_order
        self.hierarchy = hierarchy
        self.perturbative_expansion = perturbative_expansion
 
all_decays = []
 
 
class Decay(UFOBaseClass):
    require_args = ['particle', 'partial_widths']
 
    def __init__(self, particle, partial_widths, **opt):
        args = (particle, partial_widths)
        UFOBaseClass.__init__(self, *args, **opt)
 
        global all_decays
        all_decays.append(self)
 
        # Add the information directly to the particle
        particle.partial_widths = partial_widths
 
all_form_factors = []
 
 
class FormFactor(UFOBaseClass):
    require_args = ['name', 'type', 'value']
 
    def __init__(self, name, type, value, **opt):
        args = (name, type, value)
        UFOBaseClass.__init__(self, *args, **opt)
 
        global all_form_factors
        all_form_factors.append(self)
 
 
all_propagators = []
 
 
class Propagator(UFOBaseClass):
 
    require_args = ['name', 'numerator', 'denominator']
 
    def __init__(self, name, numerator, denominator=None, **opt):
        args = (name, numerator, denominator)
        UFOBaseClass.__init__(self, *args, **opt)
 
        global all_propagators
        all_propagators.append(self)