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

[Andy Buckley]

Aaargh! That's the first time anyone has ever mentioned that! Is it
documented anywhere? Wouldn't it be more normal to have the '.2'
versions as the exception rather than the norm?

Maybe it should also be recommended to the collaborations that they use
this trick to dynamically work out the common block size rather than
hard-coding it... although I'm not sure if this propagates to Fortran
gens like TAUOLA, PHOTOS, etc. who might like to dig into the HEPEVT
common block and can't do this dynamic size trick.

I thought that the '.2' versions were Genser patches (hence our requests
that they be hidden from users, who shouldn't be exposed to details of
the build system patches). That makes more sense now: AGILe requests the
4000-size generators, expecting that name to be a symlink to the latest
patch version. I'll update the AGILe loader to prefer the '.2' Pythia
and Herwig libs, and these fixes will make us more robust against using
the "wrong" version in future.

Thanks for the help and clarification!
Andy


James Monk wrote:
> So in that case AGILe should probably load the xx.2 version of the
> generators
> 
> On 29 Jul 2008, at 18:12, Mikhail Kirsanov wrote:
> 
>> 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
>>>
>>
>>
>