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2017:groups:tools:lhe [2017/06/19 21:33]
leif.lnnblad
2017:groups:tools:lhe [2017/06/21 16:01]
olivier.mattelaer
Line 17: Line 17:
 == Splitting up the LHE file == == Splitting up the LHE file ==
  
-The current way of specifying the cross section is not sufficient for some matrix element generators. Requests has been made to be able to report the number of tried events in addition to the ones accepted and actually present in the file. Further more, for practical reasons, there was a request to have the possibility to report the cross section in a separate file, since when starting writing a file, the cross section is not always fully known (this is the case in HepMC where the current best estimate of the cross section is reported for each event. In addition, it is in some cases desirable to divide up a huge LHE file into several smaller ones containing equivalent events. It was therefore decided to allow to split up LHE files into one file containing the ''<​init>''​ with all information run information,​ and a list of files containing only ''<​event>''​s. For this we introduced a new ''<​eventfiles>''​ tag which may contain an arbitrary number of ''<​eventfile>''​ tags. The ''<​eventfiles>''​ tag does not have attributes and must be in the ''<​init>''​ block. For the ''<​eventfile>''​ tag the following attributes may be specified.+The current way of specifying the cross section is not sufficient for some matrix element generators. Requests has been made to be able to report the number of tried events in addition to the ones accepted and actually present in the file. Further more, for practical reasons, there was a request to have the possibility to report the cross section in a separate file, since when starting writing a file, the cross section is not always fully known (this is the case in HepMC where the current best estimate of the cross section is reported for each event. In addition, it is in some cases desirable to divide up a huge LHE file into several smaller ones containing equivalent events. It was therefore decided to allow to split up LHE files into one file containing the ''<​init>''​ with all information run information,​ and a list of files containing only ''<​event>'' ​tags (not enclosed in an ''<​LesHouchesEvents>''​ tag). For this we introduced a new ''<​eventfiles>''​ tag which may contain an arbitrary number of ''<​eventfile>''​ tags. The ''<​eventfiles>''​ tag does not have attributes and must be in the ''<​init>''​ block. For the ''<​eventfile>''​ tag the following attributes may be specified.
   * ''​name''​ (mandatory) is the name of the file containing ''<​event>''​s. This would preferably be a relative filename with respect to the directory where the file containing the ''<​init>''​ block resides.   * ''​name''​ (mandatory) is the name of the file containing ''<​event>''​s. This would preferably be a relative filename with respect to the directory where the file containing the ''<​init>''​ block resides.
   * ''​nevent''​ is the number of ''<​event>''​s in the file.   * ''​nevent''​ is the number of ''<​event>''​s in the file.
   * ''​ntries''​ is the number of attempts the ME generator needed to produce the events in the file. (see below).   * ''​ntries''​ is the number of attempts the ME generator needed to produce the events in the file. (see below).
 +
 +Question: Should not we allow events to be provide as .tar.gz and in that case have a conventional name (like banner.lhe) for the banner file?
  
 == Cross section information == == Cross section information ==
2017/groups/tools/lhe.txt ยท Last modified: 2017/06/21 22:49 by leif.lnnblad