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2013:groups:tools:lhef3 [2013/06/11 14:36]
leif.lnnblad created
2013:groups:tools:lhef3 [2013/10/24 22:21] (current)
leif.lnnblad [Suggestion]
Line 24: Line 24:
      * ''​mur''​ The factor multiplying the nominal renormalization scale for the event for the given weight      * ''​mur''​ The factor multiplying the nominal renormalization scale for the event for the given weight
      * ''​pdf''​ The LHAPDF code corresponding to the given weight      * ''​pdf''​ The LHAPDF code corresponding to the given weight
-  ​+     * ''​pdf2''​ The LHAPDF code corresponding to the given weight for the second beam if different from ''​pdf''​
   * ''<​weightgroup>''​ Can be used to group together <​weightinfo>​ tags. The only attribute is   * ''<​weightgroup>''​ Can be used to group together <​weightinfo>​ tags. The only attribute is
      * ''​name''​ A string which will be combined with the name attribute of the included <​weightinfo>​ tags to give the HepMC weight names.      * ''​name''​ A string which will be combined with the name attribute of the included <​weightinfo>​ tags to give the HepMC weight names.
 +
 +
 +=== In the <​event>​ block ===
 +
 +  * ''<​weight>''​ Removed and replaced by ''<​weights>''​
 +  * ''<​clustering>''​ Removed
 +  * ''<​pdfinfo>''​ Removed
 +  * ''<​weights>''​ contains a list of weights for the events given in the order they are defined by the ''<​weightinfo>''​ tags in the ''<​init>''​ block. If for some obscure reason a weight is absent, it should be anyway be included as a zero weight. Note that the weight for the nominal event is still given by ''​XWGTUP''​.
 +  * ''<​scales>''​ contains information about different scales used by the MEG in the given event. The scales are given as attributes, and any attribute name is allowed. However, only the following attributes have a pre-defined meaning and if they are missing the value in ''​SCALUP''​ is assumed:
 +    * ''​muf''​ The factorization scale (in GeV)
 +    * ''​mur''​ The renormalization scale (in GeV)
 +    * ''​mups''​ Suggested shower starting scale (in GeV)
 +
 +
 +In [[http://​home.thep.lu.se/​~leif/​LHEF]] there is a small example class which is able to read and write the suggested new format.
 +===== Further discussions =====
 +
 +There are a couple of things that still need to be discussed:
 +  * Are the weights all absolute, or are the later ones multipliers on the first? Both schemes have been suggested, but we should decide on one and specify it in the definition, rather than letting it be secretly generator-dependent. ​
 +    * **Leif:** I have always thought of this as being the absolute weights. I suggest we go for that.
 +  * Should this suggestion be version 2.1 or 3.0?
 +  * Can the tags suggested to be removed above, simply be removed or do they need to be left for backward compatibility?​ Since they probably have never really been used, it should be possible to just throw them away.
 +
  
2013/groups/tools/lhef3.1370954205.txt.gz ยท Last modified: 2013/06/11 14:36 by leif.lnnblad