Herwig72ConfigLHEF.Hw7ConfigLHEF Class Reference

Configuration class for showering LHE files from MG5_aMC@NLO or PowhegBox. More...

Inheritance diagram for Herwig72ConfigLHEF.Hw7ConfigLHEF:

Collaboration diagram for Herwig72ConfigLHEF.Hw7ConfigLHEF:

Public Member Functions
def	__init__ (self, genSeq, runArgs, run_name="Herwig", beams="pp")
def	local_pre_commands (self)
def	local_post_commands (self)
def	run (self)
	High-level function for triggering the process setup and the event generation. More...
def	lhef_mg5amc_commands (self, lhe_filename="events.lhe", me_pdf_order="NLO", usespin=True)
	Commands specific to showering of events produced with MG5_aMC@NLO. More...
def	lhef_powhegbox_commands (self, lhe_filename="events.lhe", me_pdf_order="NLO", usespin=True, usepwhglhereader=False, pwg_reader="powheg", pwg_reader_lib="libpowhegHerwig.so")
	Commands specific to showering of events produced with PowhegBox. More...

Public Attributes
	beams
	provide variables initialized by the parent class More...
	set_lhef_mg5amc_commands
	set_lhef_powhegbox_commands

Private Member Functions
def	__lhef_commands (self, lhe_filename="events.lhe", me_pdf_order="NLO", usespin=True, usepwghlhereader=False, pwg_reader="powheg", pwg_reader_lib="libpowhegHerwig.so")
	Sets up reading of events from an LHE file. More...

Detailed Description

Configuration class for showering LHE files from MG5_aMC@NLO or PowhegBox.

Example JobOptions are available in examples/LHEF and tests/athenaLHEF/jobOptions.

Process Setup and Generator Configuration

The LHE files have to follow a specific naming scheme which is detailed here. The name of the LHE file is added as the command line parameter --inputGeneratorFile to the Generate_tf.py command and can be accessed using the variable runArgs.inputGeneratorFile in the JobOptions where they can be passed to the functions lhef_mg5amc_commands or lhef_powhegbox_commands in order to communicate the LHE file names to Herwig7, e.g.

generator.lhef_mg5amc_commands(lhe_filename=runArgs.inputGeneratorFile, me_pdf_order="NLO")

or

generator.lhef_powhegbox_commands(lhe_filename=runArgs.inputGeneratorFile, me_pdf_order="NLO")

Event Generation

To trigger the actual running of Herwig7 in Athena please end the JobOptions with

# run the generator
generator.run()

More specifically, the run() function triggers the creation of the Herwig7 input file and the preparation of the run (i.e. the Herwig read step). This means, that no Herwig7 settings should be modified after calling the run() function because the changed settings would not be applied during the event generation.

Definition at line 58 of file Herwig72ConfigLHEF.py.

Constructor & Destructor Documentation

__init__()

def Herwig72ConfigLHEF.Hw7ConfigLHEF.__init__	(		self,
			genSeq,
			runArgs,
			run_name = "Herwig",
			beams = "pp"
	)

Definition at line 61 of file Herwig72ConfigLHEF.py.

  def __init__(self, genSeq, runArgs, run_name="Herwig", beams="pp"):
 
    beams = beams.upper()
    if beams not in ["EE", "EP" , "PP"]:
      raise RuntimeError(hw7Utils.ansi_format_error("Parameter 'beams' must be one of the following: ['EE', 'EP' , 'PP']"))
 
    
    super(Hw7ConfigLHEF, self).__init__(genSeq, runArgs, run_name)
 
    self.beams = beams
 
    self.set_lhef_mg5amc_commands = False
    self.set_lhef_powhegbox_commands = False
 
 

Member Function Documentation

__lhef_commands()

def Herwig72ConfigLHEF.Hw7ConfigLHEF.__lhef_commands (   self,   lhe_filename = "events.lhe",   me_pdf_order = "NLO",   usespin = True,   usepwghlhereader = False,   pwg_reader = "powheg",   pwg_reader_lib = "libpowhegHerwig.so"  )

private

Sets up reading of events from an LHE file.

Parameters

usespin	Use the spin of tau leptons from the LHE file (spins of other particles are ignored anyways)
usepwghlhereader	Uses a different LHE reader, which is able to propagte multiple event weights

Definition at line 134 of file Herwig72ConfigLHEF.py.

  def __lhef_commands(self, lhe_filename="events.lhe", me_pdf_order="NLO", usespin=True, usepwghlhereader=False, pwg_reader = "powheg", pwg_reader_lib="libpowhegHerwig.so"):
 
    if me_pdf_order not in ["LO", "NLO"]:
      raise RuntimeError(hw7Utils.ansi_format_error("Herwig7ConfigLHEF.py:__lhef_commands: Parameter 'me_pdf_order' must either be 'LO' or 'NLO'!"))
 
    if lhe_filename.endswith(".tar.gz"): # athena will decompress the LHE file for us
      lhe_filename = lhe_filename.replace(".tar.gz", ".events")
      if not os.path.isfile(lhe_filename):
        raise RuntimeError(hw7Utils.ansi_format_error("Herwig7ConfigLHEF.py:__lhef_commands: Could not find decompressed LHE file '{}'!".format(lhe_filename)))
 
    momentum_treatment = ""
    beam_commands = ""
    if self.beams == "EE":
      momentum_treatment = "Accept"
    elif self.beams == "EP":
      momentum_treatment = "RescaleEnergy"
      beam_commands = """
## Set the PDF for the LHE reader
# set /Herwig/EventHandlers/LHEReader:PDFA /Herwig/Partons/Hard{MEPDFOrder}PDF
""".format(MEPDFOrder = me_pdf_order)
    elif self.beams == "PP":
      momentum_treatment = "RescaleEnergy"
      beam_commands = """
## Set the PDF for the LHE reader
# set /Herwig/EventHandlers/LHEReader:PDFA /Herwig/Partons/Hard{MEPDFOrder}PDF
# set /Herwig/EventHandlers/LHEReader:PDFB /Herwig/Partons/Hard{MEPDFOrder}PDF
""".format(MEPDFOrder = me_pdf_order)
 
    pwg_reader_lib = "library "+pwg_reader_lib
 
    self.commands += """
## ----------------------------
## Read in Events from LHE File
## ----------------------------
 
## Create the Handler and Reader
library LesHouches.so
create ThePEG::LesHouchesEventHandler /Herwig/EventHandlers/LHEHandler
{PwgReaderLib}
create ThePEG::{PwgReader}LesHouchesFileReader /Herwig/EventHandlers/LHEReader
 
## Set LHE filename
set /Herwig/EventHandlers/LHEReader:FileName {FileName}
 
## Setup LHE event handler and LHE reader
set /Herwig/Generators/EventGenerator:EventHandler /Herwig/EventHandlers/LHEHandler
insert /Herwig/EventHandlers/LHEHandler:LesHouchesReaders 0 /Herwig/EventHandlers/LHEReader
set /Herwig/EventHandlers/LHEHandler:PartonExtractor /Herwig/Partons/{Beams}Extractor
set /Herwig/EventHandlers/LHEHandler:CascadeHandler /Herwig/Shower/ShowerHandler
set /Herwig/EventHandlers/LHEHandler:HadronizationHandler /Herwig/Hadronization/ClusterHadHandler
set /Herwig/EventHandlers/LHEHandler:DecayHandler /Herwig/Decays/DecayHandler
set /Herwig/EventHandlers/LHEHandler:WeightNormalization CrossSection
set /Herwig/EventHandlers/LHEHandler:WeightOption VarNegWeight
set /Herwig/EventHandlers/LHEReader:IncludeSpin {IncludeSpin}
set /Herwig/EventHandlers/LHEReader:MomentumTreatment {MomentumTreatment}
set /Herwig/EventHandlers/LHEReader:AllowedToReOpen No
 
## Parton shower settings
set /Herwig/Shower/ShowerHandler:MaxPtIsMuF Yes
set /Herwig/Shower/ShowerHandler:RestrictPhasespace Yes
# treatment of wide angle radiation
set /Herwig/Shower/PartnerFinder:PartnerMethod Random
set /Herwig/Shower/PartnerFinder:ScaleChoice Partner
 
## Don't use any cuts on LHE files
create ThePEG::Cuts /Herwig/Cuts/NoCuts
set /Herwig/EventHandlers/LHEReader:Cuts /Herwig/Cuts/NoCuts
 
{BeamCommands}
""".format(FileName = lhe_filename,
           PwgReaderLib = pwg_reader_lib if usepwghlhereader else "",
           PwgReader = pwg_reader if usepwghlhereader else "",
           Beams = self.beams,
           IncludeSpin = "Yes" if usespin else "No",
           MomentumTreatment = momentum_treatment,
           BeamCommands = beam_commands)
 
 

lhef_mg5amc_commands()

def Herwig72ConfigLHEF.Hw7ConfigLHEF.lhef_mg5amc_commands	(		self,
			lhe_filename = "events.lhe",
			me_pdf_order = "NLO",
			usespin = True
	)

Commands specific to showering of events produced with MG5_aMC@NLO.

Parameters

[in]	lhe_filename	name of the LHE file that is to be showered
[in]	me_pdf_order	order (either LO or NLO) of the matrix element PDF. This has to be consistent with the PDF used in the hard process generation and the PDF set with generator.me_pdf_commands.

The reason for these specific settings is that for MC@NLO-like matching schemes the subtraction of the parton shower contribution in the hard process and the parton shower settings have to be consistent in order to recover the correct terms at the NLO.

For showering of previously existing LHE files

generator.lhef_powhegbox_commands(lhe_filename=runArgs.inputGeneratorFile)

will work.

Definition at line 231 of file Herwig72ConfigLHEF.py.

  def lhef_mg5amc_commands(self, lhe_filename="events.lhe", me_pdf_order="NLO", usespin=True):
 
    if me_pdf_order not in ["LO", "NLO"]:
      raise RuntimeError(hw7Utils.ansi_format_error("Herwig7ConfigLHEF.py:lhef_mg5amc_commands: Parameter 'me_pdf_order' must either be 'LO' or 'NLO'!"))
 
    self.set_lhef_mg5amc_commands = True
 
    self.__lhef_commands(lhe_filename, me_pdf_order, usespin)
 
    self.commands += """
## Commands specific to showering of events produced with MG5_aMC@NLO
set /Herwig/Shower/KinematicsReconstructor:ReconstructionOption General
set /Herwig/Shower/KinematicsReconstructor:InitialInitialBoostOption LongTransBoost
set /Herwig/Shower/KinematicsReconstructor:InitialStateReconOption Rapidity
set /Herwig/Shower/ShowerHandler:SpinCorrelations No
"""
     
    # this option is not available anymore in Herwig 7.2:
    if os.environ['HERWIG7VER'].startswith('7.1'):
      self.command += """set /Herwig/Shower/KinematicsReconstructor:FinalStateReconOption Default"""
 

lhef_powhegbox_commands()

def Herwig72ConfigLHEF.Hw7ConfigLHEF.lhef_powhegbox_commands	(		self,
			lhe_filename = "events.lhe",
			me_pdf_order = "NLO",
			usespin = True,
			usepwhglhereader = False,
			pwg_reader = "powheg",
			pwg_reader_lib = "libpowhegHerwig.so"
	)

Commands specific to showering of events produced with PowhegBox.

Parameters

[in]	lhe_filename	name of the LHE file that is to be showered
[in]	me_pdf_order	order (either LO or NLO) of the matrix element PDF. This has to be consistent with the PDF used in the hard process generation and the PDF set with generator.me_pdf_commands.
[in]	usespin
[in]	usepwghlhereader

Specifying the LHE file name with

generator.lhef_powhegbox_commands(lhe_filename=runArgs.inputGeneratorFile)

should work both for showering existing LHE files as well as for on-the-fly (OTF) running of PowhegBox and Herwig7.

Since for OTF running the LHE file generated by PowhegBox is usually called PowhegOTF._1.events using

generator.lhef_powhegbox_commands(lhe_filename="PowhegOTF._1.events")

will normally also work in this case. If a different name for the LHE file generated by PowhegBox is specified with the --outputTXTFile argument to Generate_tf.py then PowhegControl will update the value of runArgs.inputGeneratorFile accordingly and

generator.lhef_powhegbox_commands(lhe_filename=runArgs.inputGeneratorFile)

should still work.

If you want to use the pwglhereader, needed to propagte multiple event weights you need to use a gridpack that contains the powhegHerwig.so

Definition at line 286 of file Herwig72ConfigLHEF.py.

  def lhef_powhegbox_commands(self, lhe_filename="events.lhe", me_pdf_order="NLO", usespin=True, usepwhglhereader=False, pwg_reader = "powheg", pwg_reader_lib="libpowhegHerwig.so"):
 
    if me_pdf_order not in ["LO", "NLO"]:
      raise RuntimeError(hw7Utils.ansi_format_error("Herwig7ConfigLHEF.py:lhef_powhegbox_commands: Parameter 'me_pdf_order' must either be 'LO' or 'NLO'!"))
 
    self.set_lhef_powhegbox_commands = True
 
    self.__lhef_commands(lhe_filename, me_pdf_order, usespin, usepwhglhereader, pwg_reader, pwg_reader_lib)

local_post_commands()

def Herwig72ConfigLHEF.Hw7ConfigLHEF.local_post_commands

(

self

)

Definition at line 87 of file Herwig72ConfigLHEF.py.

  def local_post_commands(self):
 
    return """
## =============================================
## Local Post-Commands from Herwig7ConfigLHEF.py
## =============================================
 
saverun {} /Herwig/Generators/EventGenerator
""".format(self.run_name)
 
 
 

local_pre_commands()

def Herwig72ConfigLHEF.Hw7ConfigLHEF.local_pre_commands

(

self

)

Definition at line 76 of file Herwig72ConfigLHEF.py.

  def local_pre_commands(self):
 
    return """
## ============================================
## Local Pre-Commands from Herwig7ConfigLHEF.py
## ============================================
 
# > no local pre-commands at the moment
"""
 
 

run()

def Herwig72ConfigLHEF.Hw7ConfigLHEF.run

(

self

)

High-level function for triggering the process setup and the event generation.

Warning

Please do not modify the generator configuration in the job options after calling the run() function as the modified settings would not be applied in the event generation

Definition at line 104 of file Herwig72ConfigLHEF.py.

  def run(self):
 
    
 
    self.default_commands += self.beam_commands()
    self.default_commands += self.random_seed_commands()
    
    if not self.set_printout_commands:
      self.default_commands += self.printout_commands()
    if not self.set_physics_parameter_commands:
      self.default_commands += self.physics_parameter_commands()
    if not self.set_technical_parameter_commands:
      self.default_commands += self.technical_parameter_commands()
 
    
 
    if self.set_lhef_mg5amc_commands and self.set_lhef_powhegbox_commands:
      raise RuntimeError(hw7Utils.ansi_format_error("Please do not use both 'lhef_mg5amc_commands()' and 'lhef_powhegbox_commands()' at the same time!"))
    if not self.set_lhef_mg5amc_commands and not self.set_lhef_powhegbox_commands:
      raise RuntimeError(hw7Utils.ansi_format_error("Please use either 'lhef_mg5amc_commands()' or 'lhef_powhegbox_commands()' in the JobOptions!"))
 
    
 
    hw7Control.run(self)
 
 

Member Data Documentation

beams

Herwig72ConfigLHEF.Hw7ConfigLHEF.beams

provide variables initialized by the parent class

Definition at line 70 of file Herwig72ConfigLHEF.py.

set_lhef_mg5amc_commands

Herwig72ConfigLHEF.Hw7ConfigLHEF.set_lhef_mg5amc_commands

Definition at line 72 of file Herwig72ConfigLHEF.py.

set_lhef_powhegbox_commands

Herwig72ConfigLHEF.Hw7ConfigLHEF.set_lhef_powhegbox_commands

Definition at line 73 of file Herwig72ConfigLHEF.py.

---

The documentation for this class was generated from the following file:

• Herwig72ConfigLHEF.py