In this case we use a TCsvDS. This data source allows to read a CSV file from a RDataFrame. As a result of running this tutorial, we will produce plots of the dimuon spectrum starting from a subset of the CMS collision events of Run2010B. Dataset Reference: McCauley, T. (2014). Dimuon event information derived from the Run2010B public Mu dataset. CERN Open Data Portal. DOI: 10.7483/OPENDATA.CMS.CB8H.MFFA.
{
auto fileNameUrl = "http://root.cern.ch/files/tutorials/df014_CsvDataSource_MuRun2010B.csv";
auto fileName = "df014_CsvDataSource_MuRun2010B_cpp.csv";
auto filteredEvents =
df.Filter("Q1 * Q2 == -1")
.Define("m", "sqrt(pow(E1 + E2, 2) - (pow(px1 + px2, 2) + pow(py1 + py2, 2) + pow(pz1 + pz2, 2)))");
auto invMass =
filteredEvents.Histo1D({"invMass", "CMS Opendata: #mu#mu mass;#mu#mu mass [GeV];Events", 512, 2, 110}, "m");
invMass->DrawClone();
auto fullSpectrum =
filteredEvents.Histo1D({"Spectrum", "Subset of CMS Run 2010B;#mu#mu mass [GeV];Events", 1024, 2, 110}, "m");
double jpsiLow = 2.95;
double jpsiHigh = 3.25;
auto jpsiCut = [jpsiLow, jpsiHigh](
double m) {
return m < jpsiHigh && m > jpsiLow; };
auto jpsi =
filteredEvents.Filter(jpsiCut, {"m"})
.Histo1D({"jpsi", "Subset of CMS Run 2010B: J/#psi window;#mu#mu mass [GeV];Events", 128, jpsiLow, jpsiHigh},
"m");
auto dualCanvas =
new TCanvas(
"DualCanvas",
"DualCanvas", 800, 512);
dualCanvas->Divide(2, 1);
auto leftPad = dualCanvas->cd(1);
leftPad->SetLogx();
leftPad->SetLogy();
fullSpectrum->DrawClone("Hist");
dualCanvas->cd(2);
jpsi->DrawClone("HistP");
return 0;
}
R__EXTERN TSystem * gSystem
virtual Bool_t Cp(const char *dst, Bool_t progressbar=kTRUE, UInt_t buffersize=1000000)
Allows to copy this file to the dst URL.
virtual Bool_t AccessPathName(const char *path, EAccessMode mode=kFileExists)
Returns FALSE if one can access a file using the specified access mode.
RDataFrame MakeCsvDataFrame(std::string_view fileName, bool readHeaders=true, char delimiter=',', Long64_t linesChunkSize=-1LL)
Factory method to create a CSV RDataFrame.