ATLAS Support Center

This example shows how to run a program over all files in a certain directory, fill histograms (pT and jet mass) and save histograms in an output ROOT file.

Look at the workbook of Delphes3 Delphes3 workbook. To get started, install Delphes. You should see the library “libDelphes.so”. The you can browser the ROOT tree as:

gSystem->Load("libDelphes");
TFile::Open("delphes_output.root");
Delphes->Draw("Electron.PT");
TBrowser browser;

This assumes that Delphes3 is already installed. You have the directory “Delphes3” with the shared file “libDelphes.so” inside.

Get the analysis file: antup.tgz

tar -zvxf antup.tgz
cd antup

So you will see 2 directories:

delphes3
antup

Now go to the directory “antup” and link the existing Delphes3 installation:

ln -s  ../Delphes3  delphes

In my case, it will look as:

analysis.h
A_RUN_TEST
data.in
delphes -> ../Delphes3/
main.cxx
Make_input
out

Check that you see the shared Delphes3 file

ls -l delphes/*so

You should see “delphes/libDelphes.so”

The main file which fills histograms is “main.cxx”. It fills some jet variables and save histograms in the ROOT file in “/out” directory.

To run the code, run “./A_RUN_TEST” which loops over the existing ROOT files. But before you do this, you will need to set “DATA_DIR” variable inside “A_RUN_TEST” to navigate to the directory with your “ROOT” files.

— Sergei Chekanov 2013/03/13 10:23