CCNU LHCb computing farm


Contact your supervisor to get an account.



  • Usually each user is allocated ~ 1GB disk space for home directory.
  • Bulk data should be put in your personal directory in /DATA
  • There is currently no limit on the CPU, RAM, and data disk usage.



  • ROOT 6.14.04: source /cvmfs/
  • ROOT 6.16.00: source /cvmfs/
  • ROOT 6.18.00: source /cvmfs/

There are other versions, or the same version with different versions of compiler, available. But try to stick to those listed here, as it's cached on CVMFS, meaning: 1) each version will take some cache volume; 2) a new version will be very slow when it's used for the first time. Add your version here if it's not in the above list yet, so the cache can be shared with others.

LHCb softwares

source /cvmfs/


The Urania package can be used to do the PID resampling Link1 link2. The CERN cetificate is necessary for using DataSets in CERN server, so please upload it and the precodures are same as that you've done for CERN server. Do not set any version of ROOT, then the package can be setup by

source /DATA/Install/setEnv/


using the version from LCG_96. Setup the environment:
source /cvmfs/
source /cvmfs/

export G4DATADIR=/DATA/Install/Geant4_data
export G4LEVELGAMMADATA=$G4DATADIR/PhotonEvaporation5.3
export G4RADIOACTIVEDATA=$G4DATADIR/RadioactiveDecay5.3
export G4REALSURFACEDATA=$G4DATADIR/RealSurface2.1.1

And compile one example:

mkdir test_example
cd test_example
cmake -DGeant4_DIR=/cvmfs/ /cvmfs/

And run the example:



on hepfarm03 source /DATA/Install/setups/


The hep_ml package can be found by the Github,hep_ml

Example of GB weight

The error occours when the GB reweight is performed on hepfarm03 :
import _tkinter # If this fails your Python may not be configured for Tk
ImportError: cannot open shared object file: No such file or directory

It can be fixed by adding the following lines :

import matplotlib

Two examples are attched at the bottom table, and gbweight.tar,where the first one is a simple example and the second one needs more knowledge of Python but is much more convenient and useful.

Example of uBoost

Before you use the codes, please note that the signal and background training root files should be merged into one file and tagged by an extra variable, such as the variable named as 'labels' with value 0,1 for each sample.


to be added

Known issues


Some words for students

Before you ask the questions, please learn to use and understand the codes by yourself, find and fix bugs of codes by yourself, and even rewrite the codes to make them more convinient to use. Then remember to update twiki by yourself. Always keep it in the mind that it's useless and helpless to improve our skills, thoughts and abilities if we only know how to use the codes rather than understand them.

Other useful computing resources

  1. IHEP cluster. Contact your supervisor for an account.
  2. CERN box proved 1 TB for each registered user
  3. CERN GitLab for code versioning. Github and GitLab are good alternatives if you don't have a CERN account.
  4. For instant messaging, Mattermost is provided by CERN, and alternatives include gitter. Both of them have markdown support allowing you to have pretty math formula. Skype is also popular in HEP community.
  5. The SWAN project provides you a computing environment using Jupyter notebook with CERN box directly accessible.
  6. The WSL (Windows subsystem Linux) can enable you to run Ubuntu and a few other distributions as a subsystem in Windows 10. You can turn it on following these instructions -- there are more than one way -- you probably can find more up to date instructions from a search engine. And for graphic server, Xming could be used.
  7. CERN openstack service can provide up to 10 vCPU for each user for "private" projects.
  8. Some examples of LHCb software including EPM, Davinci, Gauss, PIDCalib and TMVA

For administrator

How to configure the banner (on SLC6)

Edit the file: /etc/ssh/sshd_config to give the banner location:
# no default banner path
#Banner none
Banner /etc/mybanner
And put the content to /etc/mybanner. And then restart the sshd
service sshd restart

How to add new users

Follow these steps:
  1. Login hepfarm02 as root;
  2. Run the command `useradd XXXX -d /home/XXXX`, where XXXX is the desired login;
  3. Run `passwd XXXX` to have the new user set his/her password


  • It seems impossible to create the user home directory from hepfarm03 -- to be confirmed;
  • It seems the NIS system will automatically update the /etc/passwd file in hepfarm03 fairly fast, thus nothing need to do but wait for a while to be able to login hepfarm03. To be confirmed too.


  • How to change one's default shell?



-- DongliangZhang - 2019-04-16

Topic attachments
I Attachment History Action Size Date Who Comment
Compressed Zip archivetar gbweight.tar r1 manage 20.0 K 2019-05-01 - 03:35 WenhuaHu example of GB reweight
Texttxt r1 manage 3.9 K 2019-05-01 - 03:35 WenhuaHu example of GB reweight
Compressed Zip archivetar uBoost.tar r1 manage 340.0 K 2019-06-26 - 09:56 WenhuaHu example of uBoost
Edit | Attach | Watch | Print version | History: r18 < r17 < r16 < r15 < r14 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r18 - 2019-09-18 - DongliangZhang
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    Sandbox All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright & 2008-2019 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback