DVCS software and MySQL database

C. Muñoz Camacho

Date: February, 2005

Abstract:

The current CVS head (tag DB3) allows to easily communicate with the MySQL database. Main features are explained below, with a sample macro. Please give a try and report any problems.

1 Main features

In order to easily analyze a chain of files involving different parameters (calibration coefficients, positions of detectors, pedestal values, reference shapes, etc), a new external object is created when the DVCS library is loaded. This objects can check if the run number of the current event in the chain has changed and if so, it resets all appropiate constants to the corresponding values by querying the MySQL database.

A new class inheriting from TChain, named TDVCSChain, will take care of this check at every call of TDVCSChain::GetEntry(int).

At a user level, you only need to replace your usual declaration of TChain

TChain *tree = new TChain(``T'');

by

TDVCSChain *tree = new TDVCSChain(``T'');

All the rest will happen automatically. A message will be printed every time a run change is detected and constants reset.

Note that you can also use a chain of files for analyzing only one file and benefit of this automatization.

Waveform analysis initialization is time-consuming. If you don't need it, you can turn it off by typing:

gdvcs->SetWF(0);

after loading the DVCS library.

2 Current initializations

Currently the following parameters are initialized from the database at every run change:

• ARS pedestals for all three DVCS detectors
• Calorimeter calibration coefficients to be used with waveform analysis (from run number 3229 on).
• Waveform analysis reference shapes for all three detectors. Calorimeter ones have been obtained from the second elastic calibration runs and are different for each block. Proton array and veto ones are only preliminary and the same for all blocks of each detector.
• Calorimeter survey results.

All the other information is still missing.

3 Sample macro

The following macro shows a typical example involving several runs with different constants. It shows the calorimeter energy resolution for the second and third elastic calibrations using waveform analysis and the corresponding calibration coefficients from the database.

{
gSystem->Load("libDVCS.so");
gROOT->SetStyle("Plain");
//gdvcs->SetWF(0); //If you don't need waveform analysis

TH1F *h1=new TH1F("h1","Energy resolution",100,-1,1);
TH1F *h2=new TH1F("h2","Energy resolution",100,-1,1);
h2->SetLineColor(kRed);

//Sets WF analysis parameters (not in database yet)
TARSWave *wt=new TARSWave(128);
wt->SetFirstWindow(-10,10,"data");
wt->SetSecondWindow(-10,10,-50,50,"data");
wt->SetChi20(0.1);wt->SetChi21(180);wt->SetChi22(1e10);

TCanvas *can=new TCanvas();
/////////////////////////////////////////////////////
//My DVCS chain//////////////////////////////////////
TDVCSChain *tree=new TDVCSChain("T");
tree->Add("/work/dvcs/carlos/elas/dvcs_*.root");
//Elastic files from the 2nd and 3rd elastic calibrations loaded

TDVCSEvent *ev=new TDVCSEvent();
THRS *hrs;tree->SetBranchAddress("event_spectro.",&hrs);
TCaloEvent *caloev;tree->SetBranchAddress("event_calo.",&caloev);
Double_t v;tree->SetBranchAddress("rpl.z",&v);
Int_t nev=tree->GetEntries();
//nev=1000;
Double_t ebeam=5.767;
TLorentzVector pini(0.,0.,0.,0.938272);
TLorentzVector eini(0.,0.,ebeam,ebeam);
for(Int_t i=0;i<nev;i++){
  Int_t ObjectNumber=TProcessID::GetObjectCount();
  if(i%1000==0) cout<<i<<"/"<<nev<<endl;
  tree->GetEntry(i);
  //if(i%100==0) gObjectTable->Print();

  TLorentzVector *proton=hrs->GetParticle();  
  TLorentzVector theovec=(eini+pini-(*proton));
			  
  Int_t nb=caloev->GetNbBlocks();
  for(Int_t j=0;j<nb;j++){
    TCaloBlock *block=caloev->GetBlock(j);
    TARSWave *wave=caloev->GetWave(j);
    wave->SubstractPedestalDB(block->GetBlockNumber(),"CALO");
    wave->SetNbChannel(block->GetBlockNumber(),"CALO");
    wave->Analyze("data");
    //Visualization : always visualize waveform analysis first
    //to check parameters
//  if(caloev->GetCaloTrigger()->GetADCValue(block->GetBlockNumber())>20){
//  cout<<"Arrival time : "<<wave->GetArrivalTime1()<<endl;
//  cout<<"Amplitude : "<<wave->GetAmplitude1()<<endl;
//  wave->GetFit("data")->Draw(can,-2000,200);
//  wave->DrawSignal(can,"same");
//  wave->GetFit("data")->GetHisto()->SetLineColor(kRed);
//  wave->GetFit("data")->GetHisto()->SetDrawOption("same");
//  cout<<"Chi2="<<wave->GetChi2()<<endl;
//  cout<<"Amp 1 "<<wave->GetAmplitude1()<<"    Time1 "<<wave->GetArrivalTime1()<<endl;
//  if(wave->GetNbPulses()>1) cout<<"Amp 2 "<<wave->GetAmplitude2()<<"    Time2 "<<wave->GetArrivalTime2()<<endl;
//         	}
    //End visualization
    if(wave->GetNbPulses()>0 && wave->GetAmplitude1()>0.){
      if(abs(wave->GetArrivalTime1())<8) 
	block->SetBlockEnergy(wave->GetAmplitude1()*caloev->GetCalibration()->GetCalib(block->GetBlockNumber()));
    }
  }
  ev->SetVertex(0.,0.,v*100.);
  ev->SetCaloEvent(caloev);
  caloev->DoClustering();
  
  if(caloev->GetNbClusters()==1 && TMath::Abs(v)<1.){
    caloev->GetCluster(0)->Analyze();//Force if necessary
    //Here's your photon if you need it! :
    TLorentzVector phot=ev->GetPhoton(0,2.,0);
    //At any moment after the first call to TDVCSChain::GetEntry(int)
    //you can access the current run number of the event
    if(gdvcs->GetRun(tree->GetFile()->GetName())<4995){
      h1->Fill(phot.E()-theovec.E());//First elastic calibration
    }else{
      h2->Fill(phot.E()-theovec.E());//Second elastic calibration
    }
  }
  if(i%1000==0){
    h1->Draw();h2->Draw("same");
    can->Update();
  }
  ev->Reset();//Resets the event
  TProcessID::SetObjectCount(ObjectNumber);
}	  		  
can->Print("res.ps");
}