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Analysis with DSTs. N. Amapane – INFN Torino CMS Software Tutorial November 4, 2004. Outline. Introduction What are DSTs? COBRA framework interfaces RecQuery RecCollection/FileterdRecCollection Exercise How to read a DST and make an analysis. - PowerPoint PPT Presentation
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Analysis with DSTsAnalysis with DSTs
N. Amapane – INFN Torino
CMS Software Tutorial
November 4, 2004
CMS Software Tutorial 2
OutlineOutline
Introduction What are DSTs?
COBRA framework interfaces RecQuery RecCollection/FileterdRecCollection
Exercise How to read a DST and make an analysis
Most material shown here recycled form Norbert’s presentations
CMS Software Tutorial 3
DisclaimerDisclaimer I assume that you know a bit of C++ and ORCA
This is not a ROOT tutorial
I will not talk about Grid tools to perform distributed analysis
I will not talk about how to handle METADATA and about data management in general
Pragmatic approach – I will skip some theory
ORCA is in a rapid development phase (try to use the latest greatest)
Today: ORCA_8_6_0
CMS Software Tutorial 4
IntroductionIntroduction A database of digitized events contains:
MCinfo: MC generator, SimTrack, SimVertex SimHits: (simulated hits) Digis and Associations
Reconstruction starts from this data Consists in several hierarchical steps:
Data unpacking, apply calibration, reconstruct clusters or hits Reconstruction of tracks Reconstruction of vertexes Particle identification: e, , MET, jets, b and tagging
Reconstruction is very time consuming!
CMS Software Tutorial 5
What are DSTsWhat are DSTs DSTs
Store the result of event reconstruction Provide compact information for analysis Consist of a set of homogeneous collections of
RecObjects Tracks, vertexes, muons, electrons, jets, b-jets, taus…
User Interface: RecQuery/RecConfig specify configuration RecCollection get reconstructed
objects FilteredRecCollection
CMS Software Tutorial 6
Algorithm ConfigurationAlgorithm Configuration The configuration of an algorithm is decomposed
into Algorithm name Version identifier Fixed parameters directly used by the algorithm
Do not depend on the input data If they change the reconstruction result changes Modeled by ParameterSet
Calibration parameters directly used by the algorithm Depend on the input data If they change the reconstruction result changes Modeled by CalibrationSet
Configuration of the input algorithms (components) Modeled by ComponentSet
All these compose the RecConfig
CMS Software Tutorial 7
RecQueryRecQuery User-friendly way to define RecConfigs
Only the algorithm name is mandatory All other fields are taken from the default Config
Only the parameters, components, or calibrations which need to be changed (or fixed) need to be set
You don't have to know the names of all parameters, only the ones you want to modify
For all other parameters, components and calibrations the default values are used.
You can put anything in a RecQuery, e.g. Parameter names not known to the RecAlgorithm
The check will be done when you use the RecQuery, and an exception will be thrown if it's not OK
Usage:RecQuery q("AlgorithmName"); or
RecQuery q("AlgorithmName", "Version");
CMS Software Tutorial 8
Setting the ConfigurationSetting the ConfigurationParameters are taken from:
1) Default Configuration of the algorithm (defaultConfig) That’s the only place where parameter names and types are defined
2) .orcarc: Every parameter is configurable with the following syntax AlgorithmName:ParameterName = value AlgorithmName:ComponentName = NameOfTheAlgorithm overwrites 1) For components same sequence as for parameters in a recursive way:
AlgorithmName:ComponentName:ParameterName = value The most qualified line has precedence, i.e
CombinatorialTrackFinder:SeedGenerator:ptCut = 1.2overrides GlobalPixelSeedGenerator:ptCut = 2.0
3) In the code See next slide overwrites 2)
CMS Software Tutorial 9
Setting the ConfigurationSetting the Configuration Let
Setting parameters:
Setting components:
q.setParameter("ConeSize", 0.77);
RecQuery myTF("TrackFinder"); q.setComponent("TrackReconstructor", myTF);
RecQuery q("AlgorithmName");
CMS Software Tutorial 10
RecCollectionsRecCollections RecCollection addresses the off-line analysis use case:
iterating over reconstructed objects of some type and use them directly or for further reconstruction of higher-level objects.
The collection is homogeneous: All objects in the collection are reconstructed in the same way
Within the event In all events Reproducibly
Reconstruction is “expensive” and should not be wasted: Reconstruction is done “on demand” Reconstruction results are cached for further access Reconstruction results are made persistent if desired:
RecAlgoName:Persistent = true
CMS Software Tutorial 11
RecCollectionRecCollection A RecCollection<T> ”reconstructs” objects of type T in the current event. RecCollection is a LazyObserver of RecEvent:
not reconstructed when dispatched, but only when asked for content RecCollections which are instantiated but not used "don't cost“ CPU
STL-vector-like interface: begin(), end(), size(), empty(), front(), back(), … Calling any of those triggers the actual reconstruction Since 8_6_0, semantics changes w.r.t. previous versions
Example:
RecCollection<MyRecObj> myobjects(RecQuery(“Name_of_algorithm”));
cout << myobjects.config() << endl;
cout << myobjects.exists() << endl;
cout << myobjects.size() << endl;RecCollection<MyRecObj>::const_iterator it;
MyRecObj inherits from RecObj
CMS Software Tutorial 12
RecCollectionRecCollectionRecQuery q("TrackReconstructor");
RecCollection<Track> c(q);
const Track& t1 = c.front(); // providing c.size()>0
const Track& t2 = c[2]; // providing c.size()>2
typedef RecCollection<Track>::const_iterator RI;
for ( RI i = c.begin(); i != c.end(); ++i ) { const Track& track = *i; cout << track << endl; }
cout << c.name() << " : " << c.exists() << endl; cout << c.config() << endl;if ( !c.empty() ) cout << c.size() << endl;
RecQuery q("TrackReconstructor");
RecCollection<Track> c(q);
const Track& t1 = c.front(); // providing c.size()>0
const Track& t2 = c[2]; // providing c.size()>2
typedef RecCollection<Track>::const_iterator RI;
for ( RI i = c.begin(); i != c.end(); ++i ) { const Track& track = *i; cout << track << endl; }
cout << c.name() << " : " << c.exists() << endl; cout << c.config() << endl;if ( !c.empty() ) cout << c.size() << endl;
CMS Software Tutorial 13
FilteredRecCollectionFilteredRecCollection FilteredRecCollection is a drop-in replacement for
RecCollection that adds filtering (selection) of the elements. It takes, in addition to the RecQuery argument, also a Filter<T> argument. The caller must make sure that the filter instance is not deleted during the lifetime of the FilteredRecCollection. The usual methods begin(), end(), range() and size(), etc. refer to the filtered subset of RecObjects.RecQuery q("TrackReconstructor","1.0");
Capri::Filter f; FilteredRecCollection<Track> c(q,f); FilteredRecCollection<Track>::Range r = c.range(); FilteredRecCollection<Track>::const_iterator RI;for ( RI i = r.first; i != r.second; ++i ) { const Track& track = *i; cout << track << endl; }cout << c.size() << endl; cout << c.config() << endl;
CMS Software Tutorial 14
ReadOnly ModeReadOnly ModeAdding the line
RecAlgoName:Request = ReadOnlyto the “.orcarc” file will change the behavior of a RecCollection. In this mode only objects which are already stored in a dataset can be read and the reconstruction on-demand mechanism is switched off. In case the requested collection is not stored in the dataset, a warning will show up.
• ReadOnly affects the RecCollection, and all components automatically:
• If one asks for ReadOnly BJets, they will refer to the ReadOnly TTracks and ReadOnly CaloWhatevers.
• Other RecQueries for TTrack (not via BJets) will not be affected by this:
• CombinatorialTrackFinder:Request can be Auto, and user RecCollections for TTrack may be re-reconstructed.
CMS Software Tutorial 15
DST WritingDST Writing Standard executable to run reconstruction and produce DST:
Examples/ExProduction/writeDST Takes Digi dataset as input
Simple way to choose DST contents: orcarc.writeDST Example: UseTkforDST = true
CMS Software Tutorial 16
DST Contents (I)DST Contents (I)
Level-1 triggerHLT trigger
MET from EcalPlusHcalTowers with correctionMET from CaloRecHitsMET from MC particlesMET from ICJets with Type1 correctionMET from KTJets with Type2 correctionMET from L1TriggerMET
L2 MuonsL3 MuonsStandAlone MuonsGlobal MuonsIsolated Muons
Iterative cone (0.5) jetsIterative cone (0.7) jetsIterative cone (0.5) calibrated
(JetPlusTrack) jetsIterative cone (0.5) calibrated
(GammaJet) jetsKt recom (4) jetsKt recom (1) jets
B-Jets CombinedBTagging
CMS Software Tutorial 17
DST Contents (II)DST Contents (II)
EcalPlusHcalTowersEgammaBasicClustersEgammaClustersEgammaSuperClustersEgammaEndcapClustersEgammaGtfTracksLevel2 barrel candidatesLevel2 endcap candidatesOffline barrel candidatesOffline endcap candidates
Taus PixelTauJetFinderTaus TauConeJetFinder
HLT electron tracksOffline electron tracksHLT photon candidatesOffline photon candidatesHLT electron candidatesOffline electron candidatesEgamma MC information
Tracker tracks CombinatorialTrackFinderPixel tracks PixelTrackFinderVertices PrincipalVertexFinderVertices PVFPrimaryVertexFinder
CMS Software Tutorial 18
Exercise
CMS Software Tutorial 19
TaskTask 500 H eeevents; mH = 300 GeV Read a DST Extract MC, Level-1 Trigger, HLT, muon and electron information Fill histograms Fill ROOT tree Plot fill pT spectrum of simulated and reconstructed leptons Plot di-muon/di-electron invariant mass Have a look at the interface of RecMuon and ElectronCandidate:
ORCA reference manual http://cmsdoc.cern.ch/swdev/snapshot/ORCA/ReferenceManual/html/classes.html
Optimize mass resolution: get best measurements for reconstructed muons and electrons
Plot Higgs mass
CMS Software Tutorial 20
Muon ReconstructionMuon Reconstruction For the time being we have four different muon reconstruction
algorithms implemented: StandAloneMuonReconstructor GlobalMuonReconstructor L2MuonReconstructor L3MuonReconstructor
All four algorithms are RecAlgorithm<RecMuon> inheriting from RecAlgorithm<T>
RecMuon inherits from TTrack (RecObj) Easy access to reconstructed muons
RecQuery q("<Name of Reconstructor>");RecCollection<RecMuon> theCollection(q);for (RecCollection<RecMuon>::const_iterator it = theCollection.begin(); it != theCollection.end(); ++it)cout << "Muon: " << (*it) << endl;
CMS Software Tutorial 21
Electron ReconstructionElectron Reconstruction Offline electrons: Simply add to your BuildFile:
<lib name=EgammaOfflineReco>
Offline reconstruction of electrons and photons: EgammaCandidateFinder EgammaOfflineElectronFinder EgammaOfflinePhotonFinder EgammaOfflineElectronTracking
#include “ElectronPhoton/EgammaOfflineReco/interface/OfflineElectronReco.h”RecCollection<ElectronCandidate> theCollection(OfflineElectronReco::defaultQuery());for (RecCollection<ElectronCandidate>::const_iterator it = theCollection.begin(); it != theCollection.end(); ++it)cout << ”Electron: " << (*it) << endl;
CMS Software Tutorial 22
First StepFirst Step
wget http://home.cern.ch/amapane/ORCATutorial/goDST
chmod +x goDST
./goDST
CMS Software Tutorial 23
Second StepSecond Stepcd ORCA_8_1_3/src/Workspace
You will find the following files:BuildFileorcarcORCAExercise.cppMyAnalysis.hMyAnalysis.ccTry to understand the code!
Modify MyAnalysis.cc
scram b recompileeval `scram runtime -csh` set runtime environmentTutorial -c orcarc run executableroot start ROOT
CMS Software Tutorial 24
HomeworkHomework
Plot the invariant mass of the Higgs (and win the Nobel Prize)
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