Differences

This shows you the differences between two versions of the page.

--- fcs:eic:intro [2017/02/07 22:16]
hepsim17 [EVGEN single particle studies]
+++ fcs:eic:intro [2017/04/04 15:36] (current)
hepsim17 [Using C++]
@@ Line 65: / Line 65: @@
 fpad check_promc_single.py
 </code>
-It makes a few distributions. You can try to calculate Q2 and x_bj using position and energy of the truth-level electrons. Look at the [[:usage_analysis|Analysis tutorial]].
+It makes a few distributions. You can try to calculate Q2 and x_bj using position and energy of the truth-level electrons. Look at the [[:hepsim:usage_analysis|Analysis tutorial]].
 You can download all files as:
@@ Line 93: / Line 93: @@
 You can run such scripts using "fpad" (Linux/Mac) or jaspp GUI (Windows).
-<note tip>Look at the tutorial [[community:hepsim:usage_full|here]] which shows how  to use C++/ROOT  for  reading  SLCIO files. We show this Python example since it does not require compilation, and you can run it on Windows. For more sophisticated studies that involve FastJet and other tools, use C++/ROOT.</note>
+<note tip>Look at the tutorial [[:hepsim:usage_full|here]] which shows how  to use C++/ROOT  for  reading  SLCIO files. We show this Python example since it does not require compilation, and you can run it on Windows. For more sophisticated studies that involve FastJet and other tools, use C++/ROOT.</note>
 Here is an example of plotting the distribution of pseudorapidity for truth and reconstructed electrons:
@@ Line 162: / Line 162: @@
   * fake rate (cannot be done with this sample!)
   * calculate Q2 and x_bj, check efficiency and resolutions for these variable
-====== Displaying reconstructed events ======
+====== Reconstructed events ======
@@ Line 192: / Line 193: @@
+====== Using C++ ======
+You can read SLCIO files using a C++ program. As usual, your program can look as this:
+<code cpp>
+string input="data.slcio";
+LCReader* lcReader = LCFactory::getInstance()->createLCReader() ;
+lcReader->open( infile1.c_str() ) ;
+LCEvent*  evt;
+int nEvents=0;
+while( (evt = lcReader->readNextEvent()) != 0 ) {
+      if (nEvents==0) UTIL::LCTOOLS::dumpEvent( evt ) ;
+           cout << "  Run : " << evt->getRunNumber() << " Detector: "      << evt->getDetectorName() <<  endl ;
+           const LCParameters& params=evt->getParameters();
+           // print stored EVGEN parameters
+           StringVec floatKeys ;
+           int nFloatParameters = params.getFloatKeys( floatKeys ).size() ;
+           for(int i=0; i< nFloatParameters ; i++ ){
+              FloatVec floatVec ;
+              params.getFloatVals(  floatKeys[i], floatVec ) ;
+              int nFloat  = floatVec.size()  ;
+              cout << " parameter " << floatKeys[i] << " [float]: " ;
+              for(int j=0; j< nFloat ; j++ ){
+                    cout << floatVec[j] << ", " ;
+                }
+               cout << endl ;
+               }
+   nEvents ++ ;
+   }
+  lcReader->close() ;
+</code>
+This code example shows how to print float parameters from the EVGEN level (copied from the input ProMC).
+Here is the example of all parameters (float, integers, strings):
+<hidden>
+<code cpp>
+ parameter EVGEN:Code [int]: 10,
+ parameter EVGEN:DIS:ISR [int]: 0,
+ parameter EVGEN:ID1 [int]: 11,
+ parameter EVGEN:ID2 [int]: 2212,
+ parameter EVGEN:ProcessID [int]: 10,
+ parameter EVGEN:AlphaQCD [float]: 0.00255778,
+ parameter EVGEN:AlphaQED [float]: 0.243193,
+ parameter EVGEN:DIS:Q2 [float]: 12.4407,
+ parameter EVGEN:DIS:W [float]: 69.6586,
+ parameter EVGEN:DIS:XBJ [float]: 0.00255778,
+ parameter EVGEN:DIS:YBJ [float]: 0.243193,
+ parameter EVGEN:EventsRequested [float]: 50000,
+ parameter EVGEN:PDF1 [float]: 0,
+ parameter EVGEN:PDF2 [float]: 0,
+ parameter EVGEN:Scale [float]: 69.6586,
+ parameter EVGEN:ScalePDF [float]: 12.4407,
+ parameter EVGEN:SigmaErrorPB [float]: 737.376,
+ parameter EVGEN:SigmaPB [float]: 164882,
+ parameter EVGEN:Weight [float]: 1,
+ parameter EVGEN:X1 [float]: 0.00255778,
+ parameter EVGEN:X2 [float]: 0.243193,
+ parameter EVGEN:eCM [float]: 141,
+ parameter _weight [float]: 1,
+ parameter EVGEN:Process [string]: e-p,
+ parameter GEANT4_VERSION [string]: 10.2.0,
+ parameter HepSim [string]: 1.1,
+ parameter ProcessID [string]: -1,
+ parameter SLIC_VERSION [string]: 5.0.0,
+</code>
+</hidden>
+For EIC ep events, the relevant parameters for a given DIS event are:
+<code cpp>
+ parameter EVGEN:eCM [float]: 141
+ parameter EVGEN:Process [string]: e-p
+ parameter EVGEN:ID1 [int]: 11
+ parameter EVGEN:ID2 [int]: 2212
+ parameter EVGEN:ProcessID [int]: 10
+ parameter EVGEN:DIS:Q2 [float]: 12.4407      // Truth-level Q^2
+ parameter EVGEN:DIS:W [float]: 69.6586       // Truth-level W
+ parameter EVGEN:DIS:XBJ [float]: 0.00255778  // Truth_level x_bjorken
+ parameter EVGEN:DIS:YBJ [float]: 0.243193    // Truth_level y_bjorken
+</code>
+Note that SLCIO files have two records representing truth level MC: MCParticle and MCInfo. MCInfo includes information on generated events.
+See the example how this record was created in [[https://github.com/Argonne-National-Laboratory/ProMC/blob/master/examples/promc2lcio/promc2lcio.java|promc2lcio.java]]
  --- //[[[email protected]|Sergei Chekanov]] 2016/09/19 07:06//