Changes in README.md [d836f45:44b0a31] in git

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• README.md (modified) (1 diff)

README.md

@@ -5 +5 @@
 
 More details can be found on the Delphes website http://cp3.irmp.ucl.ac.be/projects/delphes
+
+Quick start with Delphes
+========================
+
+Commands to get the code:
+
+```
+   wget http://cp3.irmp.ucl.ac.be/downloads/Delphes-3.4.1.tar.gz
+
+   tar -zxf Delphes-3.4.1.tar.gz
+```
+
+Commands to compile the code:
+
+```
+   cd Delphes-3.4.1
+
+   make
+```
+
+Finally, we can run Delphes:
+
+```
+   ./DelphesHepMC
+```
+
+Command line parameters:
+
+```
+   ./DelphesHepMC config_file output_file [input_file(s)]
+     config_file - configuration file in Tcl format
+     output_file - output file in ROOT format,
+     input_file(s) - input file(s) in HepMC format,
+     with no input_file, or when input_file is -, read standard input.
+```
+
+Let's simulate some Z->ee events:
+
+```
+   wget http://cp3.irmp.ucl.ac.be/downloads/z_ee.hep.gz
+   gunzip z_ee.hep.gz
+   ./DelphesSTDHEP cards/delphes_card_CMS.tcl delphes_output.root z_ee.hep
+```
+
+or
+
+```
+   curl -s http://cp3.irmp.ucl.ac.be/downloads/z_ee.hep.gz | gunzip | ./DelphesSTDHEP cards/delphes_card_CMS.tcl delphes_output.root
+```
+
+For more detailed documentation, please visit https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook
+
+Configure Delphes on lxplus.cern.ch
+====================================
+
+```
+git clone git://github.com/delphes/delphes.git Delphes
+
+cd Delphes
+
+source  /afs/cern.ch/sw/lcg/external/gcc/4.9.3/x86_64-slc6/setup.sh
+
+source /afs/cern.ch/sw/lcg/app/releases/ROOT/6.06.00/x86_64-slc6-gcc49-opt/root/bin/thisroot.sh
+
+make 
+```
+
+Simple analysis using TTree::Draw
+=================================
+
+Now we can start [ROOT](root.cern) and look at the data stored in the output ROOT file.
+
+Start ROOT and load Delphes shared library:
+
+```
+   root -l
+   gSystem->Load("libDelphes");
+```
+
+Open ROOT file and do some basic analysis using Draw or TBrowser:
+
+```
+   TFile::Open("delphes_output.root");
+   Delphes->Draw("Electron.PT");
+   TBrowser browser;
+```
+
+Notes:
+* ```Delphes``` is the tree name. It can be learned e.g. from TBrowser.
+* ```Electron```is the branch name; ```PT``` is a variable (leaf) of this branch.
+
+Complete description of all branches can be found in [doc/RootTreeDescription.html](doc/RootTreeDescription.html).
+This information is also available [in the workbook](https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook/RootTreeDescription).
+
+Macro-based analysis
+====================
+
+Analysis macro consists of histogram booking, event loop (histogram filling),
+histogram display.
+
+Start ROOT and load Delphes shared library:
+
+```
+   root -l
+   gSystem->Load("libDelphes");
+```
+
+Basic analysis macro:
+
+```
+{
+  // Create chain of root trees
+  TChain chain("Delphes");
+  chain.Add("delphes_output.root");
+  
+  // Create object of class ExRootTreeReader
+  ExRootTreeReader *treeReader = new ExRootTreeReader(&chain);
+  Long64_t numberOfEntries = treeReader->GetEntries();
+  
+  // Get pointers to branches used in this analysis
+  TClonesArray *branchElectron = treeReader->UseBranch("Electron");
+
+  // Book histograms
+  TH1 *histElectronPT = new TH1F("electron pt", "electron P_{T}", 50, 0.0, 100.0);
+
+  // Loop over all events
+  for(Int_t entry = 0; entry < numberOfEntries; ++entry)
+  {
+
+    // Load selected branches with data from specified event
+    treeReader->ReadEntry(entry);
+  
+    // If event contains at least 1 electron
+    if(branchElectron->GetEntries() > 0)
+    {
+      // Take first electron
+      Electron *electron = (Electron*) branchElectron->At(0);
+      
+      // Plot electron transverse momentum
+      histElectronPT->Fill(electron->PT);
+      
+      // Print electron transverse momentum
+      cout << electron->PT << endl;
+    }
+
+  }
+
+  // Show resulting histograms
+  histElectronPT->Draw();
+}
+```
+
+More advanced macro-based analysis
+==================================
+
+The 'examples' directory contains ROOT macros [Example1.C](examples/Example1.C), [Example2.C](examples/Example2.C) and [Example3.C](examples/Example3.C).
+
+Here are the commands to run these ROOT macros:
+
+```
+   root -l
+   .X examples/Example1.C("delphes_output.root");
+```
+
+or
+
+```
+   root -l examples/Example1.C'("delphes_output.root")'
+```