Notes for the g-2 Offline use
These instructions are derived from the notes which were taped into the detector logbook on how to use the offline. Before noting anything else it should be pointed out that the
main offline account is the g2off account on the physgi01.phy.bnl.gov computer.
If you would like to know the password for that account
just mail to Dave Zimmerman
and ask him nicely.
NEW!!! How to read tapes in physics!
There is now a tape drive in physics which can be used to play back the
data which we are writing to tape. Charles has created a
friendly interface which
allows us to read files off it. The drive is
available for tape mounting in the RHIC printer
room. When bringing copied data tapes to physics
please remember to put them on the
tape storage shelf in room 1-102 (Ofer and Stratos' office)
For those of you interested in more detailed information and stuff like that
regarding the offline, check out the
Offline Documentation page. It has all sorts of the hottest latest
and greatest information about how you too can become an offline maven.
The heart of the quick documentation
There are several different ways of running the g2 analysis code. They range
from the quick and easy to use runoff to the
onliney onoff to the full power of the
offline itself.
Ofer's Runoff Tool
This tool allows you to quickly determine specified data regarding a
particular run. At present it gives a count of how many electrons there are
in a particular run. Where the electron's are defined according to
the definition which can be found the file countem.f
in the ~g2off/g2off directory.
This code is run by typing
runoff XXX (where XXX is the run number for the run which you wish
to analyze)
The runoff script ftp's the relevant data file from the online cluster
and brings it to physgi where it is analyzed.
The Offline version of the online
analysis:: OnOff
This program enables you to run online.f over data in the offline
part of the computing world. The program can be used by typing
onoff filename (or device name if you are using a tape)
as an example of this sort of behavior you could do::
cd ~g2off/unidir/unitape/examples
to get to the right directory
onoff /dev/mt/tps7d5nsvc
then it asks for a copy tapedrive. The answer is none. Then it
reads in the configuration file and "it goes...".
This creates the online histograms and allows you to copy the raw data to
disk or tape. You can then use paw to access the histograms which are
thereby created.
The Offline in all its glory
The first step in the offline analysis on physgi is to make certain that
the data which you wish to analyze is in the appropriate directory. That
being the directory:: g2off/ring97/data
Now you are ready to do the analysis. First go to the g2off
subdirectory (so youll be in ~g2off/g2off in this case...) and type
g2off
to get into the g2off program interface (looks like PAW,
dont it? Gotta love KUIP)
Now you have a choice. We can do this the hard way or the easy way.
The easy way is to use the g2run.kumac to do all the
setting up commands for you. You can do that by typing
exec ~/g2run
If you opted for this easy option you should click
here to skip the next few steps.
But for those of you who like manual transmissions, word processing in
latex and baking your own bagels you wont be satisfied with that. You'll
wanna type the following series of commands out yourself.
algo defna
to use the default pulse finding algorithm (Dont know how to make my own
pulse finding algoriddem yet)
/g2off/default/set adcmin -1
This establishes the treatment of the ADC words in the WFD record
setenv G2OUTFILE $G2DATA/g2gaf.fz
This will cause the g2gaf adamo file to be placed on the $G2DATA disk
at the end of the job.
Now you are ready to setup your input file. To do this you type
the following...
setenv g2infile $G2DATA/r0000XXX.dat
Please note that the file must actually be there for this process to work.
If the run which you want to analyze isnt there ftp it to that directory
from the online cluster.
Now you're all set to go...type
run
and then.....
Next YYYYY
where the YYYYY are the number of events in that run
which you wish to analyze. Now you will receive the mother of all
error messages. Ignore the man behind the curtain....
OK NOW WE ARE ALL TOGETHER AGAIN....
You will now
have created a file called g2gaf.fz in the directory in which youve
been running. This fz file has all sorts of potential. By merely typing
example2
you can now turn it into a useful ntuple! This ntuple will be called
g2off.paw. It is highly recommended that you rename it to something else
fast before it gets overwritten by one of your analysis colleagues.
Do this by the following tricks....
mv g2off.paw $G2DATA/../pawfiles/g2offXXX.paw
rm g2gaf.fz
move to the $G2DATA disk where this file is placed
and then type the rm command where XXX is that pesky run number again.
The file which you have created will now allow you to utilize the
full power of PAW!!!!!
Here are a listing of the variables in this ntuple.