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0001 ---
0002 title: FAQ
0003 description: FAQ
0004 name: faq
0005 layout: default
0006 ---
0007
0008 {% include layouts/title.md %}
0009
0010 The following documentation assumes that users have completed the basic training on the [ePIC landing page](https://eic.github.io/documentation/landingpage.html) or atleast have rudimentary understanding of the [eic-shell](https://eic.github.io/tutorial-setting-up-environment/02-eic-shell/index.html) container and [ROOT](https://root.cern.ch/) analysis package.
0011
0012 #### How to access input datasets and simulated results from Jefferson Lab xrootd (PREFERRED METHOD)
0013 First open `eic-shell` and connect to the xrootd filesystem
0014 ```
0015 xrdfs root://dtn-eic.jlab.org
0016 ```
0017 Then the relevant directories (EVGEN, RECO, and FULL) can be found in /volatile/eic/EPIC directory
0018 ```
0019 [dtn-eic.jlab.org:1094] / > ls /volatile/eic/EPIC
0020 /volatile/eic/EPIC/EVGEN
0021 /volatile/eic/EPIC/FULL
0022 /volatile/eic/EPIC/RECO
0023 ....................
0024 ....................
0025 ```
0026 - EVGEN: hepmc3 rootfiles for input datasets
0027 - FULL: Full geant4 simulation root files
0028 - RECO: Reconstructed root files
0029
0030 The rootfiles are organized under the categories in tagged folders that correlate to the campaigns and detector configs. To list the directories and exit out of the filesystem:
0031 ```
0032 [dtn-eic.jlab.org:1094] / > ls /volatile/eic/EPIC/RECO/23.06.1/epic_brycecanyon
0033 /volatile/eic/EPIC/RECO/23.06.1/epic_brycecanyon/DIS
0034 /volatile/eic/EPIC/RECO/23.06.1/epic_brycecanyon/SIDIS
0035
0036 [dtn-eic.jlab.org:1094] / > exit
0037 Goodbye.
0038 ```
0039 The preferred way to access a specific rootfile is to open it in root directly:
0040 ```
0041 auto f = TFile::Open("root://dtn-eic.jlab.org//volatile/eic/EPIC/RECO/23.06.1/epic_brycecanyon/DIS/NC/18x275/minQ2=1/pythia8NCDIS_18x275_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_5.1663.eicrecon.tree.edm4eic.root")
0042 ```
0043 N.B. The above command needs to be executed after opening root. Make sure to use `TFile::Open("filename")` because `new TFile("filename")` will not work. You can try doing `root "filename"` to load the file on startup.
0044
0045 It is also possible copy the file and open it locally:
0046 ```
0047 xrdcp root://dtn-eic.jlab.org//volatile/eic/EPIC/RECO/23.06.1/epic_brycecanyon/DIS/NC/18x275/minQ2=1/pythia8NCDIS_18x275_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_5.1663.eicrecon.tree.edm4eic.root .
0048 root pythia8NCDIS_18x275_minQ2=1_beamEffects_xAngle=-0.025_hiDiv_5.1663.eicrecon.tree.edm4eic.root
0049 ```
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