[Rivet] RE : RE : installation problems (It works!)

[Mikhail Kirsanov]

 Hello,
 In GENSER, .2 in the version always means HEPEVT size 10000. So, pythia 418 has a size
4000, and 418.2 has a size 10000.
 For some time we thoght that all experiments moved to 10000, but then it turned out that
CMS still uses the size 4000. For this reason, for some pythia versions there is no 4000 subversion.
                                             Mikhail


-----Original Message-----
From: James Monk [mailto:jmonk at hep.ucl.ac.uk]
Sent: Tue 7/29/2008 6:59 PM
To: Andy Buckley
Cc: Mikhail Kirsanov; Holger Schulz; genser-developers; rivet at projects.hepforge.org
Subject: Re: RE : RE : [Rivet] installation problems (It works!)
 
It seems like the max number of records in the event is actually set  
at 4000 (found in pyhepc.F as the parameter NMXHEP), which is what  
caused the problem.  The fix Andy submitted to AGILe works for me  
because NMXHEP gets copied into MSTU(8).

I have a question tho'.  It looks to me that the AGILe number of  
entries has been 10,000 for quite some time (at least as far back as  
the original AGILe 1.0 release), yet this is the first time it  
breaks.  Did NMXHEP get decreased at some point in the Genser release  
from 10,000->4000?  Is 4000 a long enough record at the LHC (I thought  
the option of 10,000 was added specifically for the LHC!).

In fact, I just checked ATLAS' Pythia interface and I see this:

HepMC::HEPEVT_Wrapper::set_max_number_entries(10000);

This is not so good, right?

-James

On 29 Jul 2008, at 17:01, Andy Buckley wrote:

> Mikhail Kirsanov wrote:
>> I would recommend to set it automatically, example is here:
>> $MCGENERATORS/pythia6/418/share/examples/main78.cc
>
> Thanks Mikhail, this seems to work for me. I've committed it to SVN -
> can you try, James?
>
>> There is the corresponding possibility also in Herwig installed
>> in GENSER, if you want I can give you example.
>
> I'd be very grateful if you could point me at it... it will be good to
> have this fragility eliminated at last!
>
> Andy
>