[Rivet] Rivet for powheg-pythia8 studies

[Liron Barak]

Hi Andy,

On Wed, Oct 23, 2013 at 1:23 PM, Andy Buckley <andy.buckley at cern.ch> wrote:

> (CC'ing the Rivet list, since these are general Rivet questions: that is
> the best contact place)
>
> On 23/10/13 07:46, Liron Barak wrote:
> > OK, thanks!
> > The plan/request was that I'll compare my powheg-pythia8 trials
> > (with/out main31/SpaceShower/TimeShower etc) with data, but the output
> > of my powheg-pythia8 trials is evgen/truthD3PDs.... can that be used
> > instead?
>
> Not directly into Rivet, because those are ATLAS-format files. But you
> can use Rivet through Athena:
> https://twiki.cern.ch/twiki/bin/viewauth/AtlasProtected/RivetForAtlas

Ok, I'll just try that one!

>
>
> > Also, there are some things I do following the paper but i'm not sure
> about:
> > 1. Should I do:
> > source rivetenv.sh
> > source agileenv.sh
> > If I use z shell? It is written at the end of the installation that it
> > is for bash....
>
> No idea! I think the sh form should work, but I'm not familiar with zsh
> (or ksh). What do you do with other setup.sh files, e.g. the ones to set
> up LCG's GCC? Let me know!
>
I used the files which are with .sh too.... I used now  source rivetenv.sh
etc too...

>
> > 2. When I do
> > agile-runmc --beams=pp:14000 Pythia6:426 (I don't have pythia6.425 on my
> > list when I do agile-runmc --list-gens)
> > I don't get anything new.... I do get prints on the screen saying:
> > Generating 10 events
> > Generator is Pythia6:426
> > Number of points... generated... trys etc
> > But I don't get any new file with the events?! It doesn't stop me from
> > continue of course....
>
> You need to use a -o flag (as in the docs) to write out the events.
>
> > 3. Do you have any Command completion for z shell? I just ignored it for
> > now...
>
> No... it was enough effort to write it for bash, and I think the zsh
> mechanism is quite different. It also doesn't work for csh.
>
> > 4. Doing 'mkfifo fifo.hepmc' just created 'fifo.hepmc' which is empty?
>
> Erm, yes. It's a FIFO -- a special "file" for piping data between
> processes.
>
> > 5. Doing 'agile-runmc Pythia6:426 -o fifo.hepmc &' just print out [1]
> > 30886 and did nothing?
>
> Did you read from the other end of the pipe?
>
> > 6. Where exactly that FIFO part used? It is not so clear to me..... so
> > I'm not sure if I should do it for each thing?
>
> You need to attach rivet to the other end of the pipe for something to
> happen. The manual covers this -- is there something we can do to
> improve it?
>
I'm not sure I understand the meaning of 'attach to the other end of the
pipe'.... or how to do it...

>
> > 7. I guess by doing 'agile-runmc Pythia6:426 --beams=LHC:14TeV -n 50 -o
> > out.hepmc' I get the needed inputs, so, how can I use my
> > evgen/truthD3PDs from powheg-pythia8 instead of that out.hepmc?
>
> Use Rivet in Athena, or use Athena to dump a .hepmc file. I would do the
> former.
>
> > 8. Will using MC_TTBAR is the right thing? It sound like the same BUT
> > with no mentioning of the comparison to data......
>
> There is no comparison to data in the MC_ analyses: they are just for
> MC-to-MC comparisons, or sanity checking. Unfortunately I don't think
> there are any public differential top observables which have been
> unfolded other than the ATLAS ttbar jet veto analysis... hence the
> difficulty in optimising generator setups for ttbar. I think the Top
> community are starting to realise this!
>
So if I get you right, there is no 'existing' way to compare the various
ttbar MCs with the data using the Rivet analysis?

>
> > 9. Which data files are used?
>
> What do you mean?
>
I meant for the data to compare to MC? Is it is AODs? D3PD3? Ntuples? etc
but I guess itis now irrelevant...

Thanks a lot
Liron

>
> Andy
>
>
>
>
> > On Tue, Oct 22, 2013 at 9:54 PM, Andy Buckley <andy.buckley at cern.ch
> > <mailto:andy.buckley at cern.ch>> wrote:
> >
> >     On 22/10/13 10:28, Liron Barak wrote:
> >     > Dear Andy,
> >     >
> >     > I try to use that Rivet tool for the comparison of the various
> >     > powheg-pythia8 options I made with data!
> >     > I'm only at section 3.1 in your paper
> >     > (http://arxiv.org/pdf/1003.0694v8.pdf) but already have a stupid
> >     > question....
> >     > What is the exactly the input of the MC? It says hepmc, but is
> >     > it HepMC.root that I get when I run Generate_trf? The
> >     evgen.pool.root I
> >     > get when I run Generate_trf? Something else? Because for some
> sherpa
> >     > trials I have *.hepmc file made by the theoreticians and I'm not
> sure
> >     > what is what?!
> >
> >     It's the "IO_GenEvent" ASCII file format that is being referred to in
> >     the manual. That's probably what the .hepmc file is -- take a look
> >     inside it. The ROOT files produced by Generate_trf are a histogram
> file
> >     and an ATLAS-specific POOL mapping respectively.
> >
> >     Andy
> >
> >     --
> >     Dr Andy Buckley, Royal Society University Research Fellow
> >     Particle Physics Expt Group, University of Glasgow / PH Dept, CERN
> >
> >
>
>
> --
> Dr Andy Buckley, Royal Society University Research Fellow
> Particle Physics Expt Group, University of Glasgow / PH Dept, CERN
>
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