-- AlexanderFedotov - 24-Jul-2010

Learning Pythia6 output for photon+jets

Links

SWGuideDataFormatTable	Data Format Tables for the Offline Guide

                                         Contents: Show Hide

• Separate RECO, AOD and SIM tables
• Data Format pages
• How to use the table
• Instructions to complete the table
• The complete table

SWGuideDataFormatGeneratorInterface	Data Formats in GeneratorInterface

                                         Contents: Show Hide

• RECO Data Formats
• How to use the table
• Using the HepMCProduct directly (only works with GEN/GENSIM)
  • Using other products (AODSIM)
  • Retrieving information on LHE event (AODSIM)

WorkBookGenParticleCandidate	Generator event format in AOD

                                         Contents: Show Hide

• 4.4 Generator event format in AOD
  • Goals of this page:
  • Contents
  • Introduction
  • GenParticle: Generator Particle Candidate
  • Generator Particles Collections
  • GenParticle Conversion from HepMCProduct
  • Decay Tree Drawing Utilities
  • Particle List Utility
  • New Dataset Format
  • Related Documents
  • Review status

SWGuideEventGeneration	Event Generation Offline Guide

                                         Contents: Show Hide

• Introduction

SWGuidePythia6Interface	Pythia6 Interface to CMSSW

                                         Contents: Show Hide

• Introduction
• Pythia6Interface in CMSSW
  • A walk-through example configuration fragment for ttbar event generation
    • Comments by Stephen Mrenna (mailto:mrenna@fnal.gov)
  • Underlying Event settings
  • Example 1: b-bbar
    • Comments by Stephen Mrenna (mailto:mrenna@fnal.gov)
  • Example 2: Higgs
  • Example 3: Z pair
  • Example 4: msugra
  • Example 5: qqJets
  • Example 6: W pair
  • Example 7: How to generate SUSY samples using an external SLHA spectrum file
  • Example 8: How to modify particle properties & decay branching ratios using a PYUPDA card file.
  • Example 9: CSA mode with Event Reweighting
  • Example 10: How to Process Externally Generated Partons with Pythia6
• How to build Pythia6Interface package
• Setting up other Pythia6 versions with CMSSW

SWGuidePhysicsTools	Physics Analysis Tools Offline Guide

                                         Contents: Show Hide

• Physics Analysis Tools
  • Purpose
  • Meetings
  • Current Projects
  • Tutorials
  • End User Analysis Tools
  • Interactive Analysis Tools
  • AOD and RECO Common Tools
  • Monte Carlo Tools
  • Histogramming and Ntuple tools
  • Event Data Model Tools
  • Statistical Tools
  • Analysis Software and Skims
  • Visualization
  • Organisation and Documents
    • Software development
    • Contacts
      • Physics Groups Contacts and Representatives
    • Notes and Publications
    • Documents and Presentations
• Physics Analysis Tools SandBox
  • Skimming
  • Development Projects
  • Superseded Developments

SWGuideCandidateModules	Common Candidate Modules

                                         Contents: Show Hide

• Purpose of this page
• Candidate Collection Combiners
• Candidate Histogrammer and Ntuple Modules
  • CandViewNtpProducer
• Candidate Filters
  • CandViewCountFilter
  • CandCountFilter
• Candidate Selectors
  • PtMinCandSelector
  • PtMinCandViewSelector
  • PtMinCandViewCloneSelector
  • EtaPtMinCandSelector
  • EtaPtMinCandViewSelector
  • EtMinCandViewSelector
  • CandSelector
  • LargestPtCandSelector
  • LargestPtCandViewSelector
  • PdgIdCandSelector
  • PdgIdCandViewSelector
  • PdgIdCandRefSelector
  • PdgIdAndStatusCandSelector
  • PdgIdAndStatusCandViewSelector
• Conversion from HepMC Generator Format
  • GenParticleProducer
  • GenParticleCandidateProducer: GenParticleCandidate Conversion from HepMCProduct
  • FastGenParticleCandidateProducer: Faster GenParticleCandidate Conversion from HepMCProduct
  • GenParticleCandidate2GenParticleProducer
• Create Candidate Adapters from AOD Objects
  • ConcreteChargedCandidateProducer
  • EcalCandidateProducer
  • CaloTowerCandidateCreator
• Candidate Matching Modules
  • TrivialDeltaRMatcher
  • MCTruthDeltaRMatcher
  • MCTruthDeltaRMatcherNew
• Other Common Producer Modules
  • Merging Candidate Collections
  • Reducing Candidate Collections to Kinematics Content only
  • Producing a Collection of Clones
  • Producing a Collection of Shallow Clones
• Analyzer Modules
  • Produce a Set of Standard Kinematic Histograms
  • ParticleTreeDrawer Utility
  • ParticleDecayDrawer Utility
  • ParticleListDrawer Utility

Products

All GEN-SIM-RECO products

A GEN-SIM-RECO file

The following dataset of Pythya6 origin was chosen for tests:

• /RelValPhotonJets_Pt_10/CMSSW_3_7_0-START37_V4-v1/GEN-SIM-RECO
  • 9000 evs in 5 files: More... Close

replace PoolSource.fileNames = {
        '/store/relval/CMSSW_3_7_0/RelValPhotonJets_Pt_10/GEN-SIM-RECO/START37_V4-v1/0026/028B3ACD-8E69-DF11-8530-002618943877.root',
        '/store/relval/CMSSW_3_7_0/RelValPhotonJets_Pt_10/GEN-SIM-RECO/START37_V4-v1/0024/EA7C9196-3A69-DF11-B02C-00304867BF18.root',
        '/store/relval/CMSSW_3_7_0/RelValPhotonJets_Pt_10/GEN-SIM-RECO/START37_V4-v1/0024/C450BF07-3969-DF11-8F9A-00248C55CC97.root',
        '/store/relval/CMSSW_3_7_0/RelValPhotonJets_Pt_10/GEN-SIM-RECO/START37_V4-v1/0024/BE5CCD08-3869-DF11-9158-001A92971B68.root',
        '/store/relval/CMSSW_3_7_0/RelValPhotonJets_Pt_10/GEN-SIM-RECO/START37_V4-v1/0024/4E27E978-3869-DF11-BEEE-002618943925.root'
}
        

• • Its parent dataset /RelValPhotonJets_Pt_10/CMSSW_3_7_0-START37_V4-v1/GEN-SIM-DIGI-RAW-HLTDEBUG had the following pythia parameters in the config file: More... Close

process.generator = cms.EDFilter("Pythia6GeneratorFilter",
    pythiaPylistVerbosity = cms.untracked.int32(0),
    filterEfficiency = cms.untracked.double(1.0),
    pythiaHepMCVerbosity = cms.untracked.bool(False),
    comEnergy = cms.double(7000.0),
    maxEventsToPrint = cms.untracked.int32(0),
    PythiaParameters = cms.PSet(
        pythiaUESettings = cms.vstring('MSTJ(11)=3     ! Choice of the fragmentation function', 
            'MSTJ(22)=2     ! Decay those unstable particles', 
            'PARJ(71)=10 .  ! for which ctau  10 mm', 
            'MSTP(2)=1      ! which order running alphaS', 
            'MSTP(33)=0     ! no K factors in hard cross sections', 
            'MSTP(51)=10042 ! structure function chosen (external PDF CTEQ6L1)', 
            'MSTP(52)=2     ! work with LHAPDF', 
            'MSTP(81)=1     ! multiple parton interactions 1 is Pythia default', 
            'MSTP(82)=4     ! Defines the multi-parton model', 
            'MSTU(21)=1     ! Check on possible errors during program execution', 
            'PARP(82)=1.8387   ! pt cutoff for multiparton interactions', 
            'PARP(89)=1960. ! sqrts for which PARP82 is set', 
            'PARP(83)=0.5   ! Multiple interactions: matter distrbn parameter', 
            'PARP(84)=0.4   ! Multiple interactions: matter distribution parameter', 
            'PARP(90)=0.16  ! Multiple interactions: rescaling power', 
            'PARP(67)=2.5    ! amount of initial-state radiation', 
            'PARP(85)=1.0  ! gluon prod. mechanism in MI', 
            'PARP(86)=1.0  ! gluon prod. mechanism in MI', 
            'PARP(62)=1.25   ! ', 
            'PARP(64)=0.2    ! ', 
            'MSTP(91)=1      !', 
            'PARP(91)=2.1   ! kt distribution', 
            'PARP(93)=15.0  ! '),
        processParameters = cms.vstring('MSEL=10              ! Pythia Photon+Jet processes', 
            'CKIN(3)=10.          ! minimum pt hat for hard interactions'),
        parameterSets = cms.vstring('pythiaUESettings', 
            'processParameters')
    )
)
        

List of products

The full list of products in the above dataset was obtained by

• copying one event to a separate file ( copy job )
• applying the edmDumpEventContent utility to the one-event file
  • the output

Another type of the list was obtained by running the EventContentAnalyzer

• the list

Product sizes

The product sizes were obtained with the edmEventSize utility ( SWGuideEdmEventSize , WorkBook reference )

edmEventSize -v -o out rfio:///castor/cern.ch/cms//store/relval/CMSSW_3_7_0/RelValPhotonJets_Pt_10/GEN-SIM-RECO/START37_V4-v1/0024/EA7C9196-3A69-DF11-B02C-00304867BF18.root

• the output file out

Note: the two reported numbers for a products are the average plain and compressed sizes (in bytes).

The sum of compressed sizes over all products, 355757 bytes, can be compared to the average record size = (file length) / nEvents = 746345755/2000 = 373173 . => The overhead for the event structure seems to be about 5% .

Generator products

A table from SWGuideDataFormatGeneratorInterface with links corrected:

InputTag/Module (Instance name)	Container	Description
GeneratorInterface collections (in RECOSIM and AODSIM)
generator	GenEventInfoProduct	General characteristics of a generated event.
generator	GenRunInfoProduct	Run-specific parameters that define event generation, such as cross-sections, etc.
GeneratorInterface collections (in RECOSIM only)
generator	edm::HepMCProduct	A tree of final-state particles that form a generated event.
generator	GenEventInfoProduct	General characteristics of a generated event.
generator	GenRunInfoProduct	Run-specific parameters that define event generation, such as cross-sections, etc.

Examples of accessing edm::HepMCProduct , GenEventInfoProduct and GenRunInfoProduct

Simple examples are given in SWGuideDataFormatGeneratorInterface in the section How_to_use_the_table

Example: fetching pthat

The example is taken from

• CMSSW/GeneratorInterface/Pythia6Interface/test/HZZ4muAnalyzer.cc

//. . .
#include "SimDataFormats/GeneratorProducts/interface/GenEventInfoProduct.h"
//. . .
void HZZ4muAnalyzer::analyze( const Event& e, const EventSetup& )
{
  Handle< GenEventInfoProduct > GenInfoHandle;
  e.getByLabel( "generator", GenInfoHandle );

  double pthat = ( GenInfoHandle->hasBinningValues() ? 
                  (GenInfoHandle->binningValues())[0] : 0.0);
//. . .

BuildFile : taking care of

While accessing a generator product, do not forget to add a coresponding line to the BuildFile . E.g., in case of GenEventInfoProduct, the following line has to be added:

<use name=SimDataFormats/GeneratorProducts>

Otherwise an unclear fatal linking error message will be issued by scramv1 b :
.../libYOUR-PACKAGE-NAME.so: undefined reference to `typeinfo for GenEventInfoProduct'
collect2: ld returned 1 exit status

reco::GenParticleCollection

Definition

In the AOD event content, the edm::HepMCProduct format of the generated event is replaced by the "lighter" (about 2 times) record/product of type

reco::GenParticleCollection

The reco::GenParticleCollection is a typedef for

std::vector < reco::GenParticle >

For an info on the reco::GenParticle , see below

GenParticleProducer

The reco::GenParticleCollection is produced from the reco::HepMCProduct by the GenParticleProducer

• CMSSW/PhysicsTools/HepMCCandAlgos/plugins/GenParticleProducer.cc

configured with the

• .../python/genParticles_cfi.py .

There are short descriptions of the module in WorkBook and SWGuide ( ? both claim that the configuration file is located in the .../data/ directory which seems to be empty actually).

GenParticleCollection in the edmDumpEventContent output

The reco::GenParticleCollection is reported in the above Full List of Pruducts as

vector<reco::GenParticle>   "genParticles"    ""   "HLT."         

There is another product with the label genParticles also originating from the GenParticleProducer :

vector<int>                 "genParticles"    ""   "HLT." 

whose content is not clear .

reco::GenParticle

• Class Reference
• header file:

#include <DataFormats/HepMCCandidate/interface/GenParticle.h>
     

• inheritance diagram:

  reco::Candidate

  

  reco::LeafCandidate

  

  reco::CompositeRefCandidateT < reco::GenParticleRefVector >

  

  reco::GenParticle

• The generator particles may contain mother and/or daughter links to particles in the same collection (picture from here):

pdgID() and status() member functions of reco::GenParticle

The material is from the WorkBook .

• pdgId() : a PDG identifier (pdg_id() in HepMC::GenParticle)
• status() : a status code (status() in HepMC::GenParticle). Standard status codes are described in HepMC manual .
  
  
  • Status codes have the following convention in Pythia:
    
    

    Value	Meaning
    0	null entry
    1	existing entry ­ not decayed or fragmented, represents the final state as given by the generator
    2	decayed or fragmented entry (i.e. decayed particle or parton produced in shower.)
    3	identifes the "hard part" of the interaction, i.e. the partons that are used in the matrix element calculation, including immediate decays of resonances. (documentation entry, defined separately from the event history. "This includes the two incoming colliding particles and partons produced in hard interaction." [ * ])
    4-­10	undefined, reserved for future standards
    11-­200	at the disposal of each model builder equivalent to a null line
    201-...­	at the disposal of the user, in particular for event tracking in the detector

    
    
  • Other generators may have more complex conventions. See, for instance:
    
    • Herwig particle codes

Example of accessing a GenParticleCollection

The example is from the WorkBook .

#include "DataFormats/HepMCCandidate/interface/GenParticle.h"

using namespace reco; // to access types reco::GenParticleCollection ,
                      //                 reco::Candidate

void MyModule::analyze(const edm::Event & event, ...) {

   // get the handle
   Handle<GenParticleCollection> genParticles;
   event.getByLabel("genParticles", genParticles);

   // loop over particles
   for(size_t i = 0; i < genParticles->size(); ++ i) {

     // the reference p to the i-th particle:
     const GenParticle & p = (*genParticles)[i];

     // get pdgId:
     int id = p.pdgId();
     // get status:
     int st = p.status();  

     // get pointer to mother (reco::Candidate type!):
     const Candidate * mom = p.mother();

     // get pt, eta, phi, mass:
     double pt = p.pt(), eta = p.eta(), phi = p.phi(), mass = p.mass();

     // get vertex components:
     double vx = p.vx(), vy = p.vy(), vz = p.vz();

     // get charge:
     int charge = p.charge();

     // get no. of daughters:
     int n = p.numberOfDaughters();

     // loop over daughters:
     for(size_t j = 0; j < n; ++ j) {

       // get pointer d to a daughter  (reco::Candidate type!):
       const Candidate * d = p.daughter( j );

       // get daughter's id:
       int dauId = d->pdgId();
       // . . . 
     }
     // . . . 
   }
}

Notes:

• The reco::GenParticle member functions mentioned in the above example, are defined as purely virtual in the base class reco::Candidate , then actually implemented in the class reco::LeafCandidate (see InheritanceDiagram ).
• There are many more inherited member functions (see links from the InheritanceDiagram ).
• Check typedef's in the reco:: namespace:
  • in the reco::Candidate Class Reference
    (corresponds to the DataFormats/Candidate/interface/Candidate.h ),
  • in the CandidateFwd.h File Reference ,
  • and (?) similar references in the inheritance chain.

Using the ParticleListDrawer plugin as a slave class in an EDAnalyzer

The ParticleListDrawer module produces the output which is similar to the one from the Pythia routine PYLIST. The plugin usage is described in SWGuide .

One can also use it directly from c++ of an EDAnalyzer. Here is an example.

1. Add into your ..._cfg.py :
   • the load statement:

process.load("SimGeneral.HepPDTESSource.pythiapdt_cfi")
        

• • • The file SimGeneral/HepPDTESSource/python/pythiapdt_cfi.py gets loaded containing

HepPDTESSource = cms.ESSource(
    "HepPDTESSource",
    pdtFileName = cms.FileInPath(
        'SimGeneral/HepPDTESSource/data/pythiaparticle.tbl'
    )
)
           

• • the ParticleListDrawerConfig parameter set to the configuration block of your Analyzer module. This parameter set will be used later on to config a ParticleListDrawer object in your code:

. . .
process.aName = cms.EDAnalyzer(
    'YourAnalyzerName',
    . . . ,
    #
    # parameter set for a ParticleListDrawer object:
    # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ParticleListDrawerConfig = cms.untracked.PSet(
        #      +--------------------------------------+   
        #         parameter                  default
        #      +--------------------------------------+   
        #         src                        "src"
        #         maxEventsToPrint           1
        #         printVertex                False 
        #         printOnlyHardInteraction   False 
        #         useMessageLogger           False
        #      +--------------------------------------+   
        src                      = cms.InputTag        ("genParticles"),
        maxEventsToPrint         = cms.untracked.int32 (-1)
        #   default settings are commented out:
        #printVertex              = cms.untracked.bool (False)
        #printOnlyHardInteraction = cms.untracked.bool (False)
        #useMessageLogger         = cms.untracked.bool (False)
    )
)
. . .
process.p = cms.Path(process.aName)
        

The name ParticleListDrawerConfig is chosen arbitrarily. Also the configuration options may be different.

1. In the YourAnalizer.cc:
   • add the following #include e.g. as the first include :

//include other plugins:
#include "PhysicsTools/HepMCCandAlgos/plugins/ParticleListDrawer.cc"
        

• • add a data member in the class prototype:

public:   // or private:
  . . .
  ParticleListDrawer * partListDr;
        

• • instantiate the object in the constructor:

YourAnalyzer::
YourAnalyzer ( const edm::ParameterSet & iConfig)
{
  partListDr = new ParticleListDrawer
    ( iConfig.getUntrackedParameterSet ("ParticleListDrawerConfig") )  ;
  . . .
        

• • finally, print the list whenever you want in the `analyze' function:

void
YourAnalyzer::
analyze ( const edm::Event      & iEvent,
	  const edm::EventSetup & iSetup)
{
  . . .
  if (. . .) partListDr -> analyze( iEvent, iSetup) ;
  . . .
        

1. Add to your BuildFile :

. . .
<use name=PhysicsTools/HepMCCandAlgos>
<use name=DataFormats/Candidate>
. . .
<export>
. . .
   <use name=PhysicsTools/HepMCCandAlgos>
   <use name=DataFormats/Candidate>
</export>
        

ParticleTreeDrawer as a slave

The use case for the ParticleTreeDrawer described in in SWGuide would be identical (up to a different configuration) to the ParticleListDrawer above if the analyze function of the ParticleTreeDrawer would not be declared private.

The way out is

• to copy the PhysicsTools/HepMCCandAlgos/plugins/ParticleTreeDrawer.cc to our package src directory,
• change private: to public: for the analyze function
• split the file into a .h and .cc (or may be (?) just rename the .cc into .h )
• and then proceed similarily to the ParticleListDrawer case

The include line should now be

//include other plugins:
//                  In the standard ParticleTreeDrawer, `analyse' is private
//                  => use a local version where it has been  made public  
//#include "PhysicsTools/HepMCCandAlgos/plugins/ParticleTreeDrawer.cc"
#include "ParticleTreeDrawer.h"

And the configuration for the ParticleTreeDrawer has to be different:

. .
process.aName = cms.EDAnalyzer(
    'YourAnalyzerName',
    . . . ,
    #
    # parameter set for a ParticleTreeDrawer object:
    # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ParticleTreeDrawerConfig = cms.untracked.PSet(
        #      +----------------------------------------------------+   
        #         parameter       default
        #      +----------------------------------------------------+   
        #         src             "src"
        #         printP4         False
        #         printPtEtaPhi   False 
        #         printVertex     False 
        #         printStatus     False
        #         printIndex      False
        #         status          empty list of statuses (means: print all)
        #      +----------------------------------------------------+   
        src           =  cms.InputTag         ("genParticles"),
        printIndex    =  cms.untracked.bool   (True),
        status        =  cms.untracked.vint32 (3)
        #    default settings are commented out:
        #printP4       =  cms.untracked.bool   (False),
        #printPtEtaPhi =  cms.untracked.bool   (False),
        #printVertex   =  cms.untracked.bool   (False),    
        #printStatus   =  cms.untracked.bool   (True),
    )
)
. . .
process.p = cms.Path(process.aName)

In the above example only the particles from the hard part of the interaction (status code = 3) are printed out. It is noteworthy that a full listing is too long and indigestible.

PYLIST's and Parton Flow sketches for ISUB=29,14,18

There are three subprocesses occuring in the file above (the subrocess number comes from the GenEventInfoProduct::signalProcessID() function, More... Close

// get handle to the GenEventInfoProduct
  edm::Handle < GenEventInfoProduct > genEvInfo ;
  iEvent.getByLabel (genEventInfoLabel_ , genEvInfo) ; 
  // get pythia subprocess:
  int pyIsub =  (int) genEvInfo -> signalProcessID () ;

):

zoom

gif

Thus, one has:

subprocess		fraction
29		93 %
14		7 %
18		.02 %
possible but not present (too low statistics?):
114		0
115		0

Some PYLIST's (the outputs of the ParticleListDrawer actually ) for the available subprocesses can be found in the following text files:

• ISUB = 29 (10 evs with pthat > 15 GeV)
• ISUB = 14 (10 evs with pthat > 15 GeV)
• ISUB = 18 (2 evs with pthat > 10 GeV)

One can also look at the parton-flow sketches made for the first few events from each of the above files: More... Close

ISUB = 29: More... Close Event 1: More... Close

Event 2: More... Close

Event 3: More... Close

Event 4: More... Close

ISUB = 14: More... Close Event 1: More... Close

Event 2: More... Close

Event 3: More... Close

ISUB = 18: More... Close Event 1: More... Close

Event 2: More... Close

Original files: gif: More... Close ISUB=29: 1 , 2 , 3 , 4 , ISUB=14: 1 , 2 , 3 , ISUB=18: 1 , 2 , fig: More... Close ISUB=29: 1 , 2 , 3 , 4 , ISUB=14: 1 , 2 , 3 , ISUB=18: 1 , 2