ALICE software for analysis: Alien, ROOT, GEANT and AliRoot, can be run on our local systems eprexa and nprhilxs2. Accounts are obtained from L. Lowe or P. Jones respectively.

These systems are running SLC4 so the new method of installating the pre-built packages via a script downloaded from MonALISA is not available. Compiling and building is 'done by hand' so you are restricted to the versions people have installed or that you can install yourself.

nprhilxs2

This machine has 36 TB of disk and 16 GB of memory so it potentially a very useful resource. The data disks are /data/dataX where X=1,2,3,4,5,6

To access the ALICE environment you should do (in bash shell of course):

source /home/alice/alice-alienx-env.sh

and choose one of the versions presented to you by the on screen prompt. These are currently (31/10/10):

* Please select an Aliroot triad in the form "ROOT Geant3 Aliroot" (you can
 source with "-n" to skip this menu, or with "-c" to clean the environment):
 1) v5-26-00b v1-11 v4-19-22-AN
 2) v5-26-00b v1-11 v4-18-Rev-12

This can then be used for local analysis. There are some data stored on /data/data2 in the 2010 directory. It is a good idea to put the data in directories which follow the same structure as the alien catalogue so that other people know what they are and can also use them. Eg:

/data/data2/2010.lsb/LHC10e/000127815/ESDs/pass1/10000127815002.200

NB once created the default is for directories to be user writable but not group writable so each person adding more data needs to have a separate directory, hence /data/data2/2010.lsb This should obviously be changed

You can get small amounts of data by going directly to the MonALISA page, navigating into the production, run etc. you would like and finding the root_archive.zip file. This can be downloaded via your browser and unpacked using unzip into the correct directory local directory.

To use the GRID you can obtain an alien token in the usual way with alien-token-init provided that you have stored your grid certificate and key in your .globus directory. Also don't forget to:

 export alien_CLOSE_SE=ALICE:'SomeStorageSite':SE

choosing the storage from the list on MonALISA beforehand otherwise you may have problems uploading to the alien file space. You could then copy data using alien directly.

NB Indiscriminate downloading of large amounts of data is officially discouraged.

Running the event display

If you have followed the steps above you can simply cd to the directory containing your AliESDs? .root and then do:

alieve '$ALICE_ROOT/EVE/macros/visscan_init.C("raw://")'

Which will bring up the full alieve interface. Several files will be downloaded via alien so there will be some initial delay and you can get grid-related problems. It seems that this method is only working where you have write access to the directory with the data in so for now that means data that you have downloaded yourself. TO DO find the way to run alieve without getting the OCDB objects from alien ie using local OCDB copies.

-- LeeBarnby - 29 Oct 2010

Topic revision: r2 - 31 Oct 2010 - 23:07:21 - LeeBarnby
 
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