// This file provides a fix for the efficiency issue related to
// the "smile" curve in the efficiency plot. The fix is to just
// fill the denominator with events for which there is at least
// one hit in the CDC or FDC. The problem that causes the inefficieny
// is internal to GEANT and has to do with it not tracking through 
// any sensitive detectors (a bug).
//
// The first part of the fix was create a new tree that had Ncdc and
// Nfdc fields that are filled for every event, regardless whether
// a track was reconstructed or not. The orginial tree filled
// these only with the hits used on a reconstructed track which
// made a cut on them biased. The new tree was created using the
// tmp_tree plugin.


void mk_eff_denominator_nhits(void)
{
	gROOT->Reset();
	
	// Open input file for correct denominator
	TFile *f = new TFile("hd_root_nhits.root");
	f->cd("TRACKING");
	TTree *trkeff = (TTree*)gROOT->FindObject("trkeff");

	// Open input file for correct numerators
	TFile *f2 = new TFile("hd_res_charged.root");
	TH2D *eff_numerator = (TH2D*)gROOT->FindObject("eff_numerator");
	TH2D *eff_numerator_wb = (TH2D*)gROOT->FindObject("eff_numerator_wb");

	// Open output file
	TFile *of = new TFile("eff_denominator_nhits.root","RECREATE");

	TH2D *eff_denominator_nhits_cut = (TH2D*)eff_numerator->Clone("eff_denominator_nhits_cut");
	TH2D *eff_denominator_nohits = (TH2D*)eff_numerator->Clone("eff_denominator_nohits");

	// Project onto denominator histo
	trkeff->Project("eff_denominator_nhits_cut", "E.pthrown.Mag():E.pthrown.Theta()*TMath::RadToDeg()", "(Ncdc+Nfdc)>0");
	trkeff->Project("eff_denominator_nohits", "E.pthrown.Mag():E.pthrown.Theta()*TMath::RadToDeg()", "(Ncdc+Nfdc)<1");

	// Create efficiency histos 
	eff_vs_p_vs_theta = (TH2D*)eff_numerator->Clone("eff_vs_p_vs_theta");
	eff_vs_p_vs_theta->Divide(eff_denominator_nhits_cut);
	eff_vs_p_vs_theta->SetTitle("Tracking Efficiency vs. total momentum and #theta angle");
	eff_vs_p_vs_theta_wb = (TH2D*)eff_numerator_wb->Clone("eff_vs_p_vs_theta_wb");
	eff_vs_p_vs_theta_wb->Divide(eff_denominator_nhits_cut);
	eff_vs_p_vs_theta_wb->SetTitle("Wire-based Tracking Efficiency vs. total momentum and #theta angle");

	// Close output file
	of->Write();
	delete of;
}