Major dielectron framework update; includes "alignment" to updates in

[u/mrichter/AliRoot.git] / PWG3 / dielectron / AliDielectronHelper.cxx

diff --git a/PWG3/dielectron/AliDielectronHelper.cxx b/PWG3/dielectron/AliDielectronHelper.cxx
new file mode 100644 (file)
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--- /dev/null
+++ b/PWG3/dielectron/AliDielectronHelper.cxx
@@ -0,0 +1,113 @@
+/*************************************************************************
+* Copyright(c) 1998-2009, ALICE Experiment at CERN, All rights reserved. *
+*                                                                        *
+* Author: The ALICE Off-line Project.                                    *
+* Contributors are mentioned in the code where appropriate.              *
+*                                                                        *
+* Permission to use, copy, modify and distribute this software and its   *
+* documentation strictly for non-commercial purposes is hereby granted   *
+* without fee, provided that the above copyright notice appears in all   *
+* copies and that both the copyright notice and this permission notice   *
+* appear in the supporting documentation. The authors make no claims     *
+* about the suitability of this software for any purpose. It is          *
+* provided "as is" without express or implied warranty.                  *
+**************************************************************************/
+
+//
+// Dielectron helper functions wrapped in a namespace
+// 
+//
+// Authors: 
+//   Jens Wiechula <Jens.Wiechula@cern.ch> 
+// 
+
+
+
+
+#include <TError.h>
+#include <TMath.h>
+#include <TObjString.h>
+#include <TObjArray.h>
+#include <TVectorD.h>
+
+#include "AliDielectronHelper.h"
+
+//_____________________________________________________________________________
+TVectorD* AliDielectronHelper::MakeLogBinning(Int_t nbinsX, Double_t xmin, Double_t xmax)
+{
+  //
+  // Make logarithmic binning
+  // the user has to delete the array afterwards!!!
+  //
+  
+  //check limits
+  if (xmin<1e-20 || xmax<1e-20){
+    Error("AliDielectronHelper::MakeLogBinning","For Log binning xmin and xmax must be > 1e-20. Using linear binning instead!");
+    return AliDielectronHelper::MakeLinBinning(nbinsX, xmin, xmax);
+  }
+  if (xmax<xmin){
+    Double_t tmp=xmin;
+    xmin=xmax;
+    xmax=tmp;
+  }
+  TVectorD *binLim=new TVectorD(nbinsX+1);
+  Double_t first=xmin;
+  Double_t last=xmax;
+  Double_t expMax=TMath::Log(last/first);
+  for (Int_t i=0; i<nbinsX+1; ++i){
+    (*binLim)[i]=first*TMath::Exp(expMax/nbinsX*(Double_t)i);
+  }
+  return binLim;
+}
+
+//_____________________________________________________________________________
+TVectorD* AliDielectronHelper::MakeLinBinning(Int_t nbinsX, Double_t xmin, Double_t xmax)
+{
+  //
+  // Make linear binning
+  // the user has to delete the array afterwards!!!
+  //
+  if (xmax<xmin){
+    Double_t tmp=xmin;
+    xmin=xmax;
+    xmax=tmp;
+  }
+  TVectorD *binLim=new TVectorD(nbinsX+1);
+  Double_t first=xmin;
+  Double_t last=xmax;
+  Double_t binWidth=(last-first)/nbinsX;
+  for (Int_t i=0; i<nbinsX+1; ++i){
+    (*binLim)[i]=first+binWidth*(Double_t)i;
+  }
+  return binLim;
+}
+
+//_____________________________________________________________________________
+TVectorD* AliDielectronHelper::MakeArbitraryBinning(const char* bins)
+{
+  //
+  // Make arbitrary binning, bins separated by a ','
+  //
+  TString limits(bins);
+  if (limits.IsNull()){
+    Error("AliDielectronHelper::MakeArbitraryBinning","Bin Limit string is empty, cannot add the variable");
+    return 0x0;
+  }
+  
+  TObjArray *arr=limits.Tokenize(",");
+  Int_t nLimits=arr->GetEntries();
+  if (nLimits<2){
+    Error("AliDielectronHelper::MakeArbitraryBinning","Need at leas 2 bin limits, cannot add the variable");
+    delete arr;
+    return 0x0;
+  }
+  
+  TVectorD *binLimits=new TVectorD(nLimits);
+  for (Int_t iLim=0; iLim<nLimits; ++iLim){
+    (*binLimits)[iLim]=(static_cast<TObjString*>(arr->At(iLim)))->GetString().Atof();
+  }
+  
+  delete arr;
+  return binLimits;
+}
+