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Changeset 145 in svn for trunk/paper/notes.tex


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Timestamp:
Jan 7, 2009, 2:02:44 AM (16 years ago)
Author:
Xavier Rouby
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first completely re-read version... houra

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  • trunk/paper/notes.tex

    r144 r145  
    996996\subsection{Getting the \textsc{Delphes} information}
    997997 
    998 \subsubsection{Contents of the \textsc{Delphes} \textsc{root} trees}
    999  
    1000 As said upwards, the \textsc{Delphes} \textsc{root} file is subdivided into three \textsc{trees}. All the branches available in those \textsc{trees} together with the reconstructed objects they correspond to are summarised here:
    1001  
     998\subsubsection{Contents of the \textsc{Delphes} ROOT trees}
     999 
     1000The \textsc{Delphes} output file (\texttt{*.root}) is subdivided into three \textit{trees}, corresponding to generator-level data, analysis object data and trigger output. These \textsc{trees} are structures that organise the output data into \textit{branches} containing data (or \textit{leaves}) related with each others, like the kinematics properties ($E$, $p_x$, $\eta$, $\ldots$) of a given particle.
     1001
     1002Here is the exhaustive list of \textit{branches} availables in these \textit{trees}, together with their corresponding physical objet and \texttt{ExRootAnalysis} class:
    10021003\begin{quote}
    10031004\begin{tabular}{lll}
    10041005{\bf GEN \textsc{tree}} & &\\
    1005 Particle & generator particles from \textsc{hepevt}     & {\verb TRootGenParticle }\\
     1006~~~Particle & generator particles from \textsc{hepevt}     & {\verb TRootGenParticle }\\
     1007& & \\
    10061008{\bf Analysis \textsc{tree}} & & \\
    1007 Jet        & Jet collection                             & {\verb TRootJet }\\
    1008 TauJet     & Collection of jets tagged as $\tau$-jets   & {\verb TRootTauJet }\\
    1009 Electron   & Collection of electrons                    & {\verb TRootElectron }\\
    1010 Muon       & Collection of muons                        & {\verb TRootMuon }\\
    1011 Photon     & Collection of photons                      & {\verb TRootPhoton }\\
    1012 Tracks     & Tracker tracks                             & {\verb TRootTracks }\\
    1013 ETmis      & Transverse missing energy information      & {\verb TRootETmis }\\
    1014 CaloTower  & Calorimetric towers                        & {\verb TRootCalo }\\
    1015 ZDChits    & ?????                                      & {\verb TRootZdcHits }\\
    1016 RP220hits  & ?????                                      & {\verb TRootRomanPotHits }\\
    1017 FP420hits  &?????                                       & {\verb TRootRomanPotHits }\\
     1009~~~Tracks     & Collection of tracks                       & {\verb TRootTracks }\\
     1010~~~CaloTower  & Calorimetric towers                        & {\verb TRootCalo }\\
     1011~~~Electron   & Collection of electrons                    & {\verb TRootElectron }\\
     1012~~~Photon     & Collection of photons                      & {\verb TRootPhoton }\\
     1013~~~Muon       & Collection of muons                        & {\verb TRootMuon }\\
     1014~~~Jet        & Collection of jets                            & {\verb TRootJet }\\
     1015~~~TauJet     & Collection of jets tagged as $\tau$-jets   & {\verb TRootTauJet }\\
     1016~~~ETmis      & Transverse missing energy information      & {\verb TRootETmis }\\
     1017~~~ZDChits    & Hits in the Zero Degree Calorimeters       & {\verb TRootZdcHits }\\
     1018~~~RP220hits  & Hits in the first proton taggers           & {\verb TRootRomanPotHits }\\
     1019~~~FP420hits  & Hits in the next proton taggers            & {\verb TRootRomanPotHits }\\
     1020& & \\
    10181021{\bf Trigger  } & &\\
    1019 TrigResult & Acceptance of different trigger bits       & {\verb TRootTrigger }\\
     1022~~~TrigResult & Acceptance of different trigger bits       & {\verb TRootTrigger }\\
    10201023\end{tabular}
    10211024\end{quote}
    1022  
    1023 The third column shows the names of the corresponding classes to be written in a \textsc{root} tree. All classes except the {\verb TRootTrigger }, the {\verb TRootETmis } and the {\verb TRootRomanPotHits } inherit from the class {\verb TRootParticle} which includes the following member functions for accessing the components:
    1024  
    1025 \begin{quote}
    1026 \begin{verbatim}
    1027  
     1025The third column shows the names of the corresponding classes to be written in a \textsc{root} tree.
     1026All classes except \texttt{TRootTrigger}, \texttt{TRootETmis} and \texttt{TRootRomanPotHits} inherit from the class \texttt{TRootParticle} which includes the following data members (stored as \textit{leaves} in \textit{branches} of the \textit{trees}):
     1027\begin{quote}
     1028\begin{verbatim}
    10281029 float E;  // particle energy in GeV
    10291030 float Px; // particle momentum vector (x component) in GeV
    10301031 float Py; // particle momentum vector (y component) in GeV
    10311032 float Pz; // particle momentum vector (z component) in GeV
    1032  
    10331033 float PT; // particle transverse momentum in GeV
    1034  float Eta; // particle pseudorapidity  float Phi; // particle azimuthal angle in rad
    1035 \end{verbatim}
    1036 \end{quote}
    1037  
    1038 In addition to their four-momentum and related quantities, additional properties are available for specific objects. Those are summarised in the following table:
     1034 float Eta; // particle pseudorapidity 
     1035 float Phi; // particle azimuthal angle in rad
     1036\end{verbatim}
     1037\end{quote}
     1038 
     1039In addition to their kinematics, some additional properties are available for specific objects:
    10391040\begin{quote}
    10401041\begin{tabular}{ll}
    1041 {\bf \texttt{Particle} leave } &\\    \texttt{  int PID;      }&\texttt{ // particle HEP ID number }\\
     1042{\bf leaves in the \texttt{Particle} branch} &\\   
     1043   \texttt{  int PID;      }&\texttt{ // particle HEP ID number }\\
    10421044   \texttt{  int Status;   }&\texttt{ // particle status }\\
    10431045   \texttt{  int M1;       }&\texttt{ // particle 1st mother }\\
    … …  
    10451047   \texttt{  int D1;       }&\texttt{ // particle 1st daughter }\\
    10461048   \texttt{  int D2;       }&\texttt{ // particle 2nd daughter }\\
    1047    \texttt{  float Charge; }&\texttt{ // electrical charge }\\
    1048    \texttt{  float T;      }&\texttt{ // particle vertex position (t component) }\\
    1049    \texttt{  float X;      }&\texttt{ // particle vertex position (x component) }\\
    1050    \texttt{  float Y;      }&\texttt{ // particle vertex position (y component) }\\
    1051    \texttt{  float Z;      }&\texttt{ // particle vertex position (z component) }\\
    1052    \texttt{  float M;      }&\texttt{ // particle mass }\\
    1053 {\bf \texttt{Electron} and \texttt{Muon} leaves } &\\
     1049   \texttt{  float Charge; }&\texttt{ // electrical charge in units of e}\\
     1050   \texttt{  float T;      }&\texttt{ // particle vertex position (t component, in mm/c) }\\
     1051   \texttt{  float X;      }&\texttt{ // particle vertex position (x component, in mm) }\\
     1052   \texttt{  float Y;      }&\texttt{ // particle vertex position (y component, in mm) }\\
     1053   \texttt{  float Z;      }&\texttt{ // particle vertex position (z component, in mm) }\\
     1054   \texttt{  float M;      }&\texttt{ // particle mass in GeV}\\
     1055\end{tabular}
     1056\end{quote}
     1057\begin{quote}
     1058\begin{tabular}{ll}
     1059{\bf Additional leaves in \texttt{Electron} and \texttt{Muon} branches} &\\
    10541060   \texttt{ int Charge } &\\
    10551061   \texttt{ bool IsolFlag } &\\
    1056 {\bf \texttt{Jet} leave }  &\\
     1062& \\
     1063{\bf Additional leaf in the \texttt{Jet} branch }  &\\
    10571064   \texttt{ bool Btag } &\\
    1058 {\bf \texttt{ZDChits} leave } &\\
    1059    \texttt{float T;        }&\texttt{ // time of flight [s] }\\
     1065& \\
     1066{\bf Additional leaves in the \texttt{ZDChits} branch } &\\
     1067   \texttt{float T;        }&\texttt{ // time of flight  in s }\\
    10601068   \texttt{ int side;      }&\texttt{ // -1 or +1 }\\
    10611069\end{tabular}
    … …  
    10641072\subsection{Running an analysis on your \textsc{Delphes} events}
    10651073 
    1066 To analyse the {\verb Root } {\verb TTree } ntuple  of \textsc{Delphes}, the simplest way is to use the {\verb Analysis_Ex.cpp } code which is coming in the {\verb Examples } repository of \textsc{Delphes}. Note that all of this is optional and done to facilitate the analysis, as the output from \textsc{Delphes} is viewable with the standard TBrowser or \textsc{root} and can be analysed using the MakeClass facility. To run the {\verb Examples/Analysis_Ex.cpp } code, the two following arguments are required: a text file containing the input \textsc{Delphes} root files to run, and the name of the output root file. To run the code:
     1074To analyse the \textsc{root} ntuple produced by \textsc{Delphes}, the simplest way is to use the {\verb Analysis_Ex.cpp } code which is coming in the {\verb Examples } repository of \textsc{Delphes}. Note that all of this is optional and done to facilitate the analyses, as the output from \textsc{Delphes} is viewable with the standard \textsc{root} \texttt{TBrowser} and can be analysed using the \texttt{MakeClass} facility.
     1075As an example, here is a simple overview of a \texttt{myoutput.root} file created by \textsc{Delphes}:
     1076\begin{quote}
     1077\begin{verbatim}
     1078me@mylaptop:~$ root -l myoutput.root
     1079root [0]
     1080Attaching file myoutput.root as _file0...
     1081root [1] .ls
     1082TFile**         myoutput.root
     1083 TFile*         myoutput.root
     1084  KEY: TTree    GEN;1   Analysis tree
     1085  KEY: TTree    Analysis;1      Analysis tree
     1086  KEY: TTree    Trigger;1       Analysis tree
     1087root [2] TBrowser t;
     1088root [3] Analysis->GetEntries()
     1089(const Long64_t)200
     1090root [4] GEN->GetListOfBranches()->ls()
     1091OBJ: TBranchElement     Event   Event_ : 0 at: 0x9108f30
     1092OBJ: TBranch    Event_size      Event_size/I : 0 at: 0x910cfd0
     1093OBJ: TBranchElement     Particle        Particle_ : 0 at: 0x910c6b0
     1094OBJ: TBranch    Particle_size   Particle_size/I : 0 at: 0x9111c58
     1095root [5] Trigger->GetListOfLeaves()->ls()
     1096OBJ: TLeafElement       TrigResult_     TrigResult_ : 0 at: 0x90f90a0
     1097OBJ: TLeafElement       TrigResult.Accepted     Accepted[TrigResult_] : 0 at: 0x90f9000
     1098OBJ: TLeafI     TrigResult_size TrigResult_size : 0 at: 0x90fb860
     1099\end{verbatim}
     1100\end{quote}
     1101The \texttt{.ls} command lists the current keys available and in particular the three \textit{tree} names.
     1102\texttt{TBrowser t} launches a browser and the \texttt{GetEntries()} method outputs the number of data in the corresponding \textit{tree}.
     1103The list of \textit{branches} or \textit{leaves} can be displayed with the \texttt{GetListOfBranches()} and \texttt{GetListOfLeaves()} methods, pointing to the \texttt{ls()} one. In particular, it is possible to shown only parts of the output, using wildcard characters (\texttt{*}):
     1104\begin{quote}
     1105\begin{verbatim}
     1106root [6] Analysis->GetListOfLeaves()->ls("*.E")
     1107OBJ: TLeafElement       Jet.E   E[Jet_] : 0 at: 0xa08bc68
     1108OBJ: TLeafElement       TauJet.E        E[TauJet_] : 0 at: 0xa148910
     1109OBJ: TLeafElement       Electron.E      E[Electron_] : 0 at: 0xa1d8a50
     1110OBJ: TLeafElement       Muon.E  E[Muon_] : 0 at: 0xa28ac80
     1111OBJ: TLeafElement       Photon.E        E[Photon_] : 0 at: 0xa33cd88
     1112OBJ: TLeafElement       Tracks.E        E[Tracks_] : 0 at: 0xa3cced0
     1113OBJ: TLeafElement       CaloTower.E     E[CaloTower_] : 0 at: 0xa4ba188
     1114OBJ: TLeafElement       ZDChits.E       E[ZDChits_] : 0 at: 0xa54a3c8
     1115OBJ: TLeafElement       RP220hits.E     E[RP220hits_] : 0 at: 0xa61e648
     1116OBJ: TLeafElement       FP420hits.E     E[FP420hits_] : 0 at: 0xa6d0920
     1117\end{verbatim}
     1118\end{quote}
     1119
     1120To draw a particular leaf, either double-click on the corresponding name in the \texttt{TBrowser} or use the \texttt{Draw} method of the corresponding \textit{tree}.
     1121\begin{quote}
     1122\begin{verbatim}
     1123root [7] Trigger->Draw("TrigResult.Accepted");
     1124\end{verbatim}
     1125\end{quote}
     1126Mathematical operations on several \textit{leaves} are possible within a given \textit{tree}:
     1127\begin{quote}
     1128\begin{verbatim}
     1129root [8] Analysis->Draw("Muon.Px * Muon.Px");
     1130root [9] Analysis->Draw("sqrt(pow(Muon.E,2) -  pow(Muon.Pz,2) + pow(Muon.PT,2))");
     1131\end{verbatim}
     1132\end{quote}
     1133Finally, to prepare an deeper analysis, the \texttt{MakeClass} method is useful:
     1134\begin{quote}
     1135\begin{verbatim}
     1136root [10] Trigger->MakeClass()
     1137Info in <TTreePlayer::MakeClass>: Files: Trigger.h and
     1138        Trigger.C generated from TTree: Trigger
     1139\end{verbatim}
     1140\end{quote}
     1141
     1142To run the \texttt{Examples/Analysis\_Ex.cpp} code, the two following arguments are required: a text file containing the input \textsc{Delphes} \textsc{root} files to run, and the name of the output \textsc{root} file.
    10671143 \begin{quote}
    10681144\begin{verbatim}
    … …  
    10711147 \end{quote}
    10721148 
    1073  
    1074  
    1075 \subsubsection{sdflksdjf}
    1076 The \texttt{Examples/Trigger\_Only.cpp} code permits to run the trigger selection separately from the general detector simulation on output \textsc{Delphes} root files. An input \textsc{Delphes} root file is mandatory as argument. The new tree containing the trigger information will be added in these file. The trigger datacard is also necessary. To run the code:
     1149\subsubsection{Adding the trigger information}
     1150The \texttt{Examples/Trigger\_Only.cpp} code permits to run the trigger selection separately from the general detector simulation on output \textsc{Delphes} root files.
     1151A \textsc{Delphes} root file is mandatory as an input argument for the \texttt{Trigger\_Only} routine.
     1152The new \textit{tree} containing the trigger result data will be appended to this file.
     1153The trigger datacard is also necessary. To run the code:
    10771154 \begin{quote}
    10781155\begin{verbatim}
    … …  
    10841161 
    10851162\begin{itemize}
    1086 \item If the { \verb FLAG_frog } was switched on, two files were created during the run of \textsc{Delphes}: {\verb DelphesToFrog.vis } and {\verb DelphesToFrog.geom }. They contain all the needed information to run frog.
    1087 \item To display the events and the geometry, you first need to compile \textsc{Frog}. Go to the {\verb Utilities/FROG } and type {\verb make }.
     1163\item If the { \verb FLAG_frog } was switched on in the smearing card, two files has been created during the run of \textsc{Delphes}: {\verb DelphesToFrog.vis } and {\verb DelphesToFrog.geom }. They contain all the needed information to run \textsc{frog}.
     1164\item To display the events and the geometry, you first need to compile \textsc{Frog}. Go to the {\verb Utilities/FROG } and type {\verb make }. This compilation is done once for all, with this geometry (i.e. as long as the \texttt{*vis} and \texttt{*geom} files do not change)
    10881165\item Go back into the main directory and type {\verb ./Utilities/FROG/frog }.
    10891166\end{itemize}
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