Implement detector benchmark for the barrel calorimeter for energy resolution

benchmarks/barrel_ecal/scripts/emcal_barrel_energy_scan_analysis.cxx

+////////////////////////////////////////
+// Read reconstruction ROOT output file
+// Plot variables
+////////////////////////////////////////
+
+#include "ROOT/RDataFrame.hxx"
+#include <iostream>
+#include <fmt/core.h>
+
+#include "dd4pod/Geant4ParticleCollection.h"
+#include "dd4pod/CalorimeterHitCollection.h"
+
+#include "TCanvas.h"
+#include "TStyle.h"
+#include "TMath.h"
+#include "TH1.h"
+#include "TF1.h"
+#include "TH1D.h"
+#include "TGraphErrors.h"
+
+using ROOT::RDataFrame;
+using namespace ROOT::VecOps;
+
+
+void save_canvas(TCanvas* c, std::string label)
+{
+  c->SaveAs(fmt::format("results/energy_scan/{}.png",label).c_str());
+  c->SaveAs(fmt::format("results/energy_scan/{}.pdf",label).c_str());
+}
+
+void save_canvas(TCanvas* c, std::string label, double E)
+{
+  std::string label_with_E = fmt::format("{}/{}", E, label); 
+  save_canvas(c, label_with_E);
+}
+void save_canvas(TCanvas* c, std::string label, std::string E_label)
+{
+  std::string label_with_E = fmt::format("{}/{}", E_label, label); 
+  save_canvas(c, label_with_E);
+}
+void save_canvas(TCanvas* c, std::string var_label, std::string E_label, std::string particle_label)
+{
+  std::string label_with_E = fmt::format("{}/emcal_barrel_{}_{}", E_label, particle_label, var_label); 
+  save_canvas(c, label_with_E);
+}
+
+std::tuple <double, double, double, double> extract_sampling_fraction_parameters(std::string particle_label, std::string E_label)
+{
+  std::string input_fname = fmt::format("sim_output/energy_scan/{}/sim_emcal_barrel_{}.root", E_label, particle_label);
+  ROOT::EnableImplicitMT();
+  ROOT::RDataFrame d0("events", input_fname);
+
+  // Thrown Energy [GeV]
+  auto Ethr = [](std::vector<dd4pod::Geant4ParticleData> const& input) {
+    auto p = input[2];
+    auto energy = TMath::Sqrt(p.psx * p.psx + p.psy * p.psy + p.psz * p.psz + p.mass * p.mass);
+    return energy;
+  };
+
+  // Number of hits
+  auto nhits = [] (const std::vector<dd4pod::CalorimeterHitData>& evt) {return (int) evt.size(); };
+
+  // Energy deposition [GeV]
+  auto Esim = [](const std::vector<dd4pod::CalorimeterHitData>& evt) {
+    auto total_edep = 0.0;
+    for (const auto& i: evt)
+      total_edep += i.energyDeposit;
+    return total_edep;
+  };
+
+  // Sampling fraction = Esampling / Ethrown
+  auto fsam = [](const double sampled, const double thrown) {
+    return sampled / thrown;
+  };
+
+  // Define variables
+  auto d1 = d0.Define("Ethr", Ethr, {"mcparticles"})
+                .Define("nhits", nhits, {"EcalBarrelHits"})
+                .Define("Esim", Esim, {"EcalBarrelHits"})
+                .Define("fsam", fsam, {"Esim", "Ethr"});
+
+  // Define Histograms
+  auto hEthr = d1.Histo1D(
+      {"hEthr", "Thrown Energy; Thrown Energy [GeV]; Events", 100, 0.0, 25.0},
+      "Ethr");
+  auto hNhits =
+      d1.Histo1D({"hNhits", "Number of hits per events; Number of hits; Events",
+                  100, 0.0, 2000.0},
+                 "nhits");
+  auto hEsim = d1.Histo1D(
+      {"hEsim", "Energy Deposit; Energy Deposit [GeV]; Events", 500, 0.0, 0.5},
+      "Esim");
+  auto hfsam = d1.Histo1D(
+      {"hfsam", "Sampling Fraction; Sampling Fraction; Events", 200, 0.0, 0.05},
+      "fsam");
+
+  // Event Counts
+  auto nevents_thrown = d1.Count();
+  std::cout << "Number of Thrown Events: " << (*nevents_thrown) << "\n";
+
+  // Draw Histograms
+  {
+    TCanvas* c1 = new TCanvas("c1", "c1", 700, 500);
+    c1->SetLogy(1);
+    auto h = hEthr->DrawCopy();
+    //h->GetYaxis()->SetTitleOffset(1.4);
+    h->SetLineWidth(2);
+    h->SetLineColor(kBlue);
+    save_canvas(c1, "Ethr", E_label, particle_label);  
+  }
+
+  {
+    TCanvas* c2 = new TCanvas("c2", "c2", 700, 500);
+    c2->SetLogy(1);
+    auto h = hNhits->DrawCopy();
+    //h->GetYaxis()->SetTitleOffset(1.4);
+    h->SetLineWidth(2);
+    h->SetLineColor(kBlue);
+    save_canvas(c2, "nhits", E_label, particle_label);
+  }
+
+  {
+    TCanvas* c3 = new TCanvas("c3", "c3", 700, 500);
+    c3->SetLogy(1);
+    auto h = hEsim->DrawCopy();
+    //h->GetYaxis()->SetTitleOffset(1.4);
+    h->SetLineWidth(2);
+    h->SetLineColor(kBlue);
+    double up_fit = h->GetMean() + 5*h->GetStdDev();
+    double down_fit = h->GetMean() - 5*h->GetStdDev();
+    h->GetXaxis()->SetRangeUser(0.,up_fit);
+    save_canvas(c3, "Esim", E_label, particle_label);
+  }
+
+  {
+    TCanvas* c4 = new TCanvas("c4", "c4", 700, 500);
+    //c4->SetLogy(1);
+    auto h = hfsam->DrawCopy();
+    //h->GetYaxis()->SetTitleOffset(1.4);
+    h->SetLineWidth(2);
+    h->SetLineColor(kBlue); 
+    double up_fit = h->GetMean() + 5*h->GetStdDev();
+    double down_fit = h->GetMean() - 5*h->GetStdDev();
+    h->Fit("gaus", "", "", down_fit, up_fit);
+    h->GetXaxis()->SetRangeUser(0.,up_fit);
+    TF1 *gaus = h->GetFunction("gaus");
+    gaus->SetLineWidth(2);
+    gaus->SetLineColor(kRed);    
+    double mean = gaus->GetParameter(1);
+    double sigma = gaus->GetParameter(2);
+    double mean_err = gaus->GetParError(1);
+    double sigma_err = gaus->GetParError(2);
+    save_canvas(c4, "fsam", E_label, particle_label);
+    return std::make_tuple(mean, sigma, mean_err, sigma_err);
+  }
+}
+
+std::vector<std::string> read_scanned_energies(std::string input_energies_fname)
+{
+    std::vector<std::string> scanned_energies;
+    std::string E_label;
+    ifstream E_file (input_energies_fname);
+    if (E_file.is_open())
+    {
+        while (E_file >> E_label)
+        {
+            scanned_energies.push_back(E_label);
+        }
+        E_file.close();
+        return scanned_energies;
+    }
+    else
+    {
+        std::cout << "Unable to open file " << input_energies_fname << std::endl;
+        abort();
+    }
+}
+
+void emcal_barrel_energy_scan_analysis(std::string particle_label = "electron")
+{
+
+  // Setting for graphs
+  gROOT->SetStyle("Plain");
+  gStyle->SetOptFit(1);
+  gStyle->SetLineWidth(2);
+  gStyle->SetPadTickX(1);
+  gStyle->SetPadTickY(1);
+  gStyle->SetPadGridX(1);
+  gStyle->SetPadGridY(1);
+  gStyle->SetPadLeftMargin(0.14);
+  gStyle->SetPadRightMargin(0.14);
+
+    auto scanned_energies = read_scanned_energies(fmt::format("sim_output/emcal_barrel_energy_scan_points_{}.txt", particle_label));
+    
+    TGraphErrors gr_fsam(scanned_energies.size()-1);
+    TGraphErrors gr_fsam_res(scanned_energies.size()-1);
+
+    for (const auto& E_label : scanned_energies) {
+        auto [fsam, fsam_res, fsam_err, fsam_res_err] = extract_sampling_fraction_parameters(particle_label, E_label);
+        auto E = std::stod(E_label);
+
+        gr_fsam.SetPoint(gr_fsam.GetN(),E,100*fsam);
+        gr_fsam.SetPointError(gr_fsam.GetN()-1,0., 100*fsam_err);
+        gr_fsam_res.SetPoint(gr_fsam_res.GetN(),E,100.0*(fsam_res/fsam));
+        auto fsam_res_rel_err = 100.0*(sqrt(pow((fsam_res_err/fsam),2)+pow((fsam_err*fsam_res)/(fsam*fsam),2)));
+        gr_fsam_res.SetPointError(gr_fsam_res.GetN()-1,0.,fsam_res_rel_err);
+    }
+    
+    TCanvas* c5 = new TCanvas("c5", "c5", 700, 500);
+    c5->cd();
+    gr_fsam.SetTitle("Sampling Fraction Scan;True Energy [GeV];Sampling Fraction [%]");
+    gr_fsam.SetMarkerStyle(20);
+    gr_fsam.Fit("pol0", "", "", 2., 20.);
+    gr_fsam.Draw("APE");
+    save_canvas(c5, fmt::format("emcal_barrel_{}_fsam_scan", particle_label));
+
+    TCanvas* c6 = new TCanvas("c6", "c6", 700, 500);
+    c6->cd();
+    TF1* func_res = new TF1("func_res", "[0]/sqrt(x) + [1]", 0.25, 20.);
+    func_res->SetLineWidth(2);
+    func_res->SetLineColor(kRed);
+    gr_fsam_res.SetTitle("Energy Resolution;True Energy [GeV];#Delta E/E [%]");
+    gr_fsam_res.SetMarkerStyle(20);
+    gr_fsam_res.Fit(func_res,"R");
+    gr_fsam_res.Draw("APE");
+    save_canvas(c6,fmt::format("emcal_barrel_{}_fsam_scan_res", particle_label));
+}