//------------------------------------------------------------
// It's a simple macro to creat one-dimentional set signal+bkg
// 15/01/2013
// A.Karavdina
//------------------------------------------------------------

void myTTreePreparation(){

  TFile *hfile = new TFile("mySample.root","RECREATE","Test 1D sig+bkg");
  TTree *treesig = new TTree("treeSig","sig");
  TTree *treebkg = new TTree("treeBkg","bkg");
  TTree *treeall = new TTree("treeAll","sig+bkg");
  Double_t sig, bkg, theta, mes, phi;
  
  // create a branches with theta
  //and probability for signal and bkg and measur=sig+bkg
  treesig->Branch("theta",&theta);
  treebkg->Branch("theta",&theta);
  treeall->Branch("theta",&theta);
  treesig->Branch("phi",&phi);
  treebkg->Branch("phi",&phi);
  treeall->Branch("phi",&phi);

  // tree->Branch("signal",&sig);
  // tree->Branch("measur",&mes);
  // tree->Branch("bkground",&bkg);
  Int_t nevent=1000000;

  //describe signal
  TF1 *fLand = new TF1("fLand","100*(TMath::Landau(x,[0],[1],0))",2,10); 
  fLand->SetParameters(4.,0.5); 
  // fLand->Draw();

 //describe bkg
  TF1 *fLin = new TF1("fLin","0.01*x+0.5",2,10); 
  // fLin->Draw();


  TRandom3 randvar;
  for (Int_t iev=0;iev<nevent;iev++) {
    Double_t ranvar = 6*randvar.Rndm();
    theta = ranvar+3;
    sig = fLand->Eval(theta);
    bkg = fLin->Eval(theta);
    mes = sig+bkg;
    Double_t ranMean = 20*randvar.Rndm();
    if(ranMean>sig) continue;
    if(ranMean<sig && ranMean>bkg){
      phi = 6.3*randvar.Rndm();
      treesig->Fill();
      treeall->Fill();
    }
    if(ranMean<bkg){
      phi = 6.3*randvar.Rndm();
      treebkg->Fill();
      treeall->Fill();
    }
    //    tree->Fill();  // fill the tree with the current event
  }
  treesig->Write();
  treebkg->Write();
  treeall->Write();
  treesig->Print();
  treebkg->Print();
  treeall->Print();
}