Changes between Version 10 and Version 11 of WorkBook/TutorialBologna

Timestamp:

Jun 9, 2016, 8:41:53 AM (8 years ago)

Author:

Michele Selvaggi

Comment:

--

WorkBook/TutorialBologna

@@ -310 +310 @@
 }}}
 
-
+=== Part IV - Write a new module ===
+
+In this section we are going to create a module called Timing. This module will take as input a collection of particles. It will produce an output collection of particles with a smeared time variable according to some user defined resolution. It will also store the initial and final time pre-smearing. 
+
+0) Copy the template module to the new one:
+{{{
+cp modules/ExampleModule.h modules/Timing.h
+cp modules/ExampleModule.cc modules/Timing.cc
+}}}
+In these two files replace all "ExampleModule" with "Timing".
+
+1) Add the Timing module in modules/ModulesLinkDef.h:
+{{{
+#include "modules/NewModule.h"
+...
+#pragma link C++ class NewModule+;
+}}}
+
+2) In the main delphes dir, type:
+{{{
+./configure
+make
+}}}
+
+You have just added your first empty module in Delphes.
+
+3) Replace the existing "Process"  method in the newly created module. Understand this piece of code. 
+    Then edit the rest of the Timing class (both the .cc and .h), in order to comply with this method. 
+
+{{{
+void Timing::Process()
+{
+  Candidate *candidate, *mother, *particle;
+  Double_t t0, tf, t0_smeared, tf_smeared;
+  const Double_t c_light = 2.99792458E8;
+
+  fItInputArray->Reset();
+  while((candidate = static_cast<Candidate*>(fItInputArray->Next())))
+  {
+
+    //access particle before delphes processing
+    particle = static_cast<Candidate*>(candidate->GetCandidates()->At(0));
+
+    //4-position before propagation
+    const TLorentzVector &initialPosition = particle->Position;
+    //4-position after propagation
+    const TLorentzVector &finalPosition   = candidate->Position;
+
+    //initial and final time (in mm)
+    t0 = initialPosition.T();
+    tf = finalPosition.T();
+
+    // apply time smearing on time after propagation
+    tf_smeared = gRandom->Gaus(tf, fTimeResolution*1.0E3*c_light);
+
+    // correct initial time
+    t0_smeared = t0 + tf_smeared - tf;
+
+    //now store these new variables
+    mother = candidate;
+    candidate = static_cast<Candidate*>(candidate->Clone());
+    candidate->AddCandidate(mother);
+
+    candidate->genT0 = t0;
+    candidate->genTF = tf;
+    candidate->T0 = t0_smeared;
+    candidate->TF = tf_smeared;
+    candidate->ErrorT = (tf_smeared - tf);
+
+    fOutputArray->Add(candidate);
+
+  }
+}
+}}}
+
+4)  Add the new variables T0, TF, genT0, genTF, ErrorT to the Candidate class.
+    You will have to edit the files classes/DelphesClasses.h and classes/DelphesClasses.cc.
+    The Candidate class is defined in classes/DelphesClasses.h. Other methods involving the
+    Candidate class are defined in classes/DelphesClasses.cc:
+
+    - Candidate (constructor)
+    - Copy
+    - Clear
+
+If this step is performed properly, you should be able to compile by typing "make"
+
+ We are not done yet... The newly computed timing information is now properly stored and propagated
+   inside Delphes. However, we have to decide which objects will display this new information.
+
+
+5) Let's store this information in Tracks. Find this classes in
+   classes/DelphesClasses.h and add the new variables. Compile.
+
+6)  Now we have to tell Delphes that we want these variables to appear in our final root tree.
+    Store these variables in the Track objects in the ProcessTracks method
+    in modules/TreeWriter.cc. Compile.
+
+
+7)  Finally, call the Timing module in the delphes_card_CMS_PileUp in the detector and configure it.
+
+    Make two different runs with 20 and 100ps. Open the output trees a plots the new interesting 
+    variables. 
+
+