MCatNLO Step 3

On this page we will use the <>.event files that were produced by MCatNLO (see step 2) and use Herwig (in Athena) to decay the tops and produce the parton shower to arrive at a physiccal result. Finally we will produce a combined ntuple (CBNT) and POOL file as was done for Rome.

1) Get organised

Again we start at again to your MCatNLO working directory area. Then create two new directories where we'll store the basic input files (basic joboptions file and other athena related files) and the output files (the combined ntuple for the generator information and POOL files).

cd /MyMCatNLO
mkdir MyMCatNLO_BASICS
mkdir MyMCatNLO_OUTPUT
mkdir MyMCatNLO_OUTPUT/InputAndLogFiles

2) Get necessary files required for Athena running

Since we have used MCatNLO to produce the ttbar momenta, we will have to signal to Herwig that it only has to decay the top quarks and must take the top-momenta from your external <>.event-file. When using Athena, this is done using a joboptions file.

Note: In addition a file that is called inparmMcAtNlo.dat is expected in your run directory that provides the location of the <>.event file and some additional input variables related to the generated samnple in MCatNLO.

(A) First get some Athena python-files in your run directory:

cd MyMCatNLO_BASICS
get_files PDGTABLE.MeV
get_files PartPropSvc.py

(B) Get the two basic input files that are job-dependent:

For each job, the script (presented in step 4) will take the two following basic-files and add the job-dependent quantities to produce a unique joboptions file per athena job.

(B1) Get the two basic input files that are job-dependent:

The first file is the joboptions file:

cp /afs/cern.ch/user/i/ivo/public/MCatNLO_scripts/joboptions_MyMCatNLO_Step3.py.BASIC .

The lines that will be changed by the script are related to the number of events, the random number seeds for the generators and the output files.

theApp.EvtMax = XNEVENTSX
AtRndmGenSvc.Seeds = ["JIMMY  XRNDJIMMY0X XRNDJIMMY1X", "JIMMY_INIT  XRNDJIMMY2X XRNDJIMMY3X",
                      "TAUOLA XRNDTAUOLA0X XRNDTAUOLA1X", "TAUOLA_INIT XRNDTAUOLA2X XRNDTAUOLA3X", 
                      "PHOTOS XRNDPHOTOS0X XRNDPHOTOS1X", "PHOTOS_INIT XRNDPHOTOS2X XRNDPHOTOS3X"]
NTupleSvc.Output     = [ "FILE1 DATAFILE='./XOutputDirCBNTX/MCatNLO.CBNT.JobXJOBNUMBERX.root' OPT='NEW'" ]
Stream1.OutputFile = "./XOutputDirPOOLX/MCatNLO.POOL.JobXJOBNUMBERX.root"

(B2) MCatNLO parameter file

The second file is a file with some McatNLO settings. Also copy this file to the basics directory.

cp /afs/cern.ch/user/i/ivo/public/MCatNLO_scripts/inparmMcAtNlo.dat.BASIC .

The lines that will be changed by the script are related to the number of events, the random number seeds for the generators and the output files.

 './XINPUTDIRX/XINPUTNAMEX'     ! event file
  XNEVENTSX                     ! number of events

3) Get the script and taylor it to your needs

The last step is to get the script and start the jobs. For each job it will:

o create a directory called Job<job#>

o create two unique input files

o copy all otehr nexessary files here and start the job

o copy output files (CBNT,POOL and Logfiles) to an output directory

o remove directory Job<job#>

First get the script itself

cd /project/atlas/users/ivov/MyMCatNLO/
cp /afs/cern.ch/users/i/ivo/public/MCatNLO_scripts/ShipOff_MyMCatNLO_Step3.py .

In the script you need to define the variables related to the input and output directories:

input_dir           = "/project/atlas/users/ivov/MyMCatNLO/MyMCatNLO_MATRIXELEMENT/"
output_dir          = "/project/atlas/users/ivov/MyMCatNLO/MyMCatNLO_OUTPUT/"
steering_files_dir  = "/project/atlas/users/ivov/MyMCatNLO/MyMCatNLO_BASICS/"

There are however also parameters related to the number of events, the number of jobs etc etc.

Nevents             =   12500
Nevents_joboptions  =       1
Njobs               =       1
f_LogFile           =       0

Important:

The variable called Nevents is linked to the number of events that are in the <>.events files. Make sure therefore that this number is the same as in the header of the <>.events file. The variable Nevents_joboptions controls the number of events that are produced in the

4)Run the script

Once the number of events and the number of jobs are defined start the run:

./ShipOff_MyMCatNLO_Step3.py

Once you get it running for a single job, set the parameter f_Logfile to 1 and produce many files.

You are finished.

To POOL files you have produced can then be transformed to AOD after full reconstruction or Atlfast.