Resolve "Add reading sampling fraction from electrons benchmarks"

Closes #38 (closed)

benchmarks/barrel_ecal/scripts/emcal_barrel_pi0_analysis.cxx

@@ -20,9 +20,11 @@
 #include "TF1.h"
 #include "TH1D.h"
 #include "TFitResult.h"
+#include <nlohmann/json.hpp>
 
 using ROOT::RDataFrame;
 using namespace ROOT::VecOps;
+using json = nlohmann::json;
 
 void emcal_barrel_pi0_analysis(const char* input_fname = "sim_output/sim_emcal_barrel_pi0.root")
 {
@@ -56,12 +58,15 @@ void emcal_barrel_pi0_analysis(const char* input_fname = "sim_output/sim_emcal_b
        {"quantity", "resolution (in %)"},
        {"target", std::to_string(resolutionTarget)}}};
 
+  json j;
+  std::ifstream prev_steps_ifstream("emcal_barrel_particles_analyses.json");
+  prev_steps_ifstream >> j;
 
   ROOT::EnableImplicitMT();
   ROOT::RDataFrame d0("events", input_fname);
 
   // Sampling Fraction
-  double samp_frac = 0.0136;
+  double samp_frac = j["electron"]["sampling_fraction"];
 
   // Thrown Energy [GeV]
   auto Ethr = [](std::vector<dd4pod::Geant4ParticleData> const& input) {