added correction for 0 multiplicity bin

[u/mrichter/AliRoot.git] / TPC / AliTPCExB.cxx

diff --git a/TPC/AliTPCExB.cxx b/TPC/AliTPCExB.cxx
index cff72361408ef0a9f814e3cab5f09d42c302978c..1f953180a84f48f83a51f30dbed21b60ab581d9e 100644 (file)
--- a/TPC/AliTPCExB.cxx
+++ b/TPC/AliTPCExB.cxx
@@ -1,4 +1,131 @@
 #include "AliTPCExB.h"
+#include "TMath.h"
+#include "TTreeStream.h"
+
+
+//
+// Abstract class for ExB effect parameterization
+// 
+//
+// 
+// The ExB correction map is stored in the calib DB
+// The lookup can be dumped to the tree:
+/*
+
+   //
+  char *storage = "local://OCDBres"
+  Int_t RunNumber=0;
+  AliCDBManager::Instance()->SetDefaultStorage(storage);
+  AliCDBManager::Instance()->SetRun(RunNumber) 
+  AliTPCExBFirst * exb = AliTPCcalibDB::Instance()->GetExB();
+  //
+  // See example macro $ALICE_ROOT/TPC/macros/AliTPCExBdraw.C 
+  //
+  .L $ALICE_ROOT/TPC/macros/AliTPCExBdraw.C 
+  Draw0(0)
+
+
+
+
+*/
+
+AliTPCExB* AliTPCExB::fgInstance = 0;
 
 ClassImp(AliTPCExB)
 
+
+void AliTPCExB::TestExB(const char* fileName) {
+  //
+  // well, as the name sais...
+  //
+  TTreeSRedirector ts(fileName);
+  Double_t x[3];
+  for (x[0]=-250.;x[0]<=250.;x[0]+=10.)
+    for (x[1]=-250.;x[1]<=250.;x[1]+=10.)
+      for (x[2]=-250.;x[2]<=250.;x[2]+=10.) {
+       Double_t d[3];
+       Correct(x,d);
+       Double_t r=TMath::Sqrt(x[0]*x[0]+x[1]*x[1]);
+       Double_t rd=TMath::Sqrt(d[0]*d[0]+d[1]*d[1]);
+       Double_t dr=r-rd;
+       Double_t phi=TMath::ATan2(x[0],x[1]);
+       Double_t phid=TMath::ATan2(d[0],d[1]);
+       Double_t dphi=phi-phid;
+       if (dphi<0.) dphi+=TMath::TwoPi();
+       if (dphi>TMath::Pi()) dphi=TMath::TwoPi()-dphi;
+       Double_t drphi=r*dphi;
+       Double_t dx=x[0]-d[0];
+       Double_t dy=x[1]-d[1];
+       Double_t dz=x[2]-d[2];
+       ts<<"positions"
+         <<"x0="<<x[0]
+         <<"x1="<<x[1]
+         <<"x2="<<x[2]
+         <<"dx="<<dx
+         <<"dy="<<dy
+         <<"dz="<<dz
+         <<"r="<<r
+         <<"phi="<<phi
+         <<"dr="<<dr
+         <<"drphi="<<drphi
+         <<"\n";
+      }
+}
+
+
+
+Double_t AliTPCExB::GetDr(Double_t r, Double_t phi, Double_t z){
+  //
+  // Static function
+  // Posibble to us it for visualization 
+  // 
+  //
+  if (!fgInstance) return 0;
+  Double_t pos0[3] = {r*TMath::Sin(phi), r*TMath::Cos(phi),z};
+  Double_t pos1[3];
+  fgInstance->Correct(pos0,pos1);
+  Double_t dx=pos1[0]-pos0[0];
+  Double_t dy=pos1[1]-pos0[1];
+  //  Double_t dz=pos1[2]-pos0[2];
+  return TMath::Sqrt(dx*dx+dy*dy);  
+}
+
+
+Double_t AliTPCExB::GetDrphi(Double_t r, Double_t phi, Double_t z){
+  //
+  //
+  //
+  if (!fgInstance) return 0;
+  Double_t pos0[3] = {r*TMath::Sin(phi), r*TMath::Cos(phi),z};
+  Double_t pos1[3];
+  fgInstance->Correct(pos0,pos1);
+  Double_t dphi=TMath::ATan2(pos1[1],pos1[0])-TMath::ATan2(pos0[1],pos0[0]);
+  return r*dphi;  
+
+}
+
+
+Double_t AliTPCExB::GetDphi(Double_t r, Double_t phi, Double_t z){
+  //
+  //
+  //
+  if (!fgInstance) return 0;
+  Double_t pos0[3] = {r*TMath::Sin(phi), r*TMath::Cos(phi),z};
+  Double_t pos1[3];
+  fgInstance->Correct(pos0,pos1);
+  Double_t dphi=TMath::ATan2(pos1[1],pos1[0])-TMath::ATan2(pos0[1],pos0[0]);
+  return dphi;  
+
+}
+
+Double_t AliTPCExB::GetDz(Double_t r, Double_t phi, Double_t z){
+  //
+  //
+  //
+  if (!fgInstance) return 0;
+  Double_t pos0[3] = {r*TMath::Sin(phi), r*TMath::Cos(phi),z};
+  Double_t pos1[3];
+  fgInstance->Correct(pos0,pos1);
+  Double_t dz=pos1[2]-pos0[2];
+  return dz;  
+}