correctionlib RDataFrame examples

CMakeLists.txt

# Example commands to build the C++ example (df.cc):
#   cmake $(correction config --cmake) .
#   make

cmake_minimum_required(VERSION 3.11)

project(correctionlibexample LANGUAGES CXX)

find_package(correctionlib REQUIRED)
set(THREADS_PREFER_PTHREAD_FLAG ON)
find_package(Threads)

find_package(ROOT REQUIRED COMPONENTS ROOTDataFrame)

add_executable(test_df df.cc)
target_link_libraries(test_df PRIVATE correctionlib ROOT::ROOTDataFrame)

df.cc

#include "TFile.h"
#include "TCanvas.h"
#include "ROOT/RDataFrame.hxx"
#include "correction.h"

using correction::CorrectionSet;
using ROOT::VecOps::RVec;

int main(int argc, char** argv) {
    auto f = TFile::Open("DY_M50_2016.root");
    auto df = ROOT::RDataFrame(*(f->Get<TTree>("Events")));

    auto cset = CorrectionSet::from_file("electron.json");
    auto cset_2016preID = cset->at("UL-Electron-ID-SF");

    auto df1 = df.Filter(
        [] (unsigned int n, const RVec<float>& pt) { return n >= 1 && pt[0] > 10.; }, {"nElectron", "Electron_pt"}
        ).Define("leadElSF",
            [cset_2016preID] (const RVec<float>& pt, const RVec<float>& eta) {
                return cset_2016preID->evaluate({"2016preVFP", "sf", "wp90iso", std::abs(eta[0]), pt[0]});
            }, {"Electron_pt", "Electron_eta"});
    auto h = df1.Histo1D("leadElSF");
    TCanvas cv{"c1"};
    h->Draw();
    cv.Update();
    cv.SaveAs("df_compiled.png");

    return 1;
}

df.py

import ROOT as gbl
import correctionlib
correctionlib.register_pyroot_binding()

f = gbl.TFile.Open("DY_M50_2016.root")
df = gbl.ROOT.RDataFrame(f.Get("Events"))

gbl.gInterpreter.Declare('auto csetEl = correction::CorrectionSet::from_file("electron.json");')
gbl.gInterpreter.Declare('auto csetEl_2016preID = csetEl->at("UL-Electron-ID-SF");')
df = df.Filter("nElectron >= 1 && Electron_pt[0] > 10.").Define(
        "leadElSF",
        ('csetEl_2016preID->evaluate({"2016preVFP", "sf", "wp90iso", '
            'std::abs(Electron_eta[0]), Electron_pt[0]})'))
h = df.Histo1D("leadElSF")
h.Draw()