[Rivet] Fwd: Ratio measurements in Rivet

[Andy Buckley]

Yes, that would work!

Fortunately the histogram files can now be very easily loaded and the
histograms played with in Python (or C++ if you want), so no need for
*quite* such a hack :-)

Andy


On 16/05/14 22:13, Ulla Blumenschein wrote:
> Hi all,
> 
> Yes, such a feature would be extremely useful.
> We also did some hack in the past, basically editing the .aida files and
> making the Rivet compare scripts believe that one of the .aida files is
> the data file  and the other the MC but this is only useful for internal
> purpose, not for any thesis/publication level.
> 
> Best, Ulla
> 
> 
> 
> 
> /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
>     Ulla Blumenschein
>     II Physik, Uni Goettingen
>     Friedrich-Hund-Platz 1, D01.110
>     phone: 0049-551-397645
> /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> 
> 
> On Fri, May 16, 2014 at 10:05 PM, Andy Buckley <andy.buckley at cern.ch
> <mailto:andy.buckley at cern.ch>> wrote:
> 
>     Hi guys,
> 
>     In case you didn't see my reply to Felix...
> 
>     Yes, Gerhard is right -- at *present* Rivet can only make histograms
>     that come from one sort of run because the finalize() step where such
>     histo combination would be done is run in each run rather than as a
>     separate process.
> 
>     The same issue means that it's hard to handle run merging for any
>     complex observable such as e.g. the asymmetry A-B/A+B of two
>     histograms... although we play a few tricks in our merging script to
>     identify simple normalized histos or ratios and not screw them up!
> 
>     This is no different from any other analysis... and it isn't hard to
>     write a custom script to retrieve the numerator and denominator histos
>     and do the division outside Rivet. However, we are working on a
>     development that will allow Rivet's finalize to be run separately, which
>     will solve these sorts of problems for once and for all, so please make
>     the analyses, add all the histograms that you can, and put in a big "///
>     @todo <insert description>" Doxygen comment into the analysis and tell
>     us about it, and we will "upgrade" it when possible!
> 
>     Andy
> 
> 
>     On 14/05/14 17:46, Gerhard Brandt wrote:
>     >
>     >
>     > Hi Monica,
>     >
>     > I think nowadays responsible are Roman and Kiran, and i put the RIVET
>     > authors in CC for good measure.
>     >
>     > We have indeed recently started discussing this issue with them and
>     > it seems that a real ratio analysis is currently not possible (at
>     least
>     > it wasn't two months ago) - I will forward previous conversation.
>     >
>     > what might be possible with some manual hacking is to run two
>     > consecutive RIVET analyses and then manually divide the histograms.
>     > I do not think this has been done, but I take it from Roman's and
>     Andy's
>     > reply that this is possible...
>     > it does not of course correctly correlate the uncertainties
>     > so the usefulness is limited, basically to the central value
>     >
>     > Gerhard
>     >
>     >
>     > On 5/14/14, 8:30 AM, Monica Dunford wrote:
>     >> Hi Ulla and Gerhard,
>     >>
>     >> A post-doc in my group was asking about ratios in Rivet (see
>     below). Do
>     >> you know anything about the status of this in Rivet? Or know who I
>     >> should speak to?
>     >>
>     >> Cheers,
>     >> Monica
>     >>
>     >>
>     >>>
>     >>> -------- Original Message --------
>     >>> Subject:     Ratio measurements in Rivet
>     >>> Date:     Mon, 12 May 2014 12:49:35 +0200
>     >>> From:     Felix Müller <fmueller at cern.ch <mailto:fmueller at cern.ch>>
>     >>> To:     hn-atlas-Generators (General discussion and questions about
>     >>> ATLAS
>     >>> MC generators) <hn-atlas-generators at cern.ch
>     <mailto:hn-atlas-generators at cern.ch>>
>     >>> CC:     Shima Shimizu <Shima.Shimizu at cern.ch
>     <mailto:Shima.Shimizu at cern.ch>>,
>     >>> "Felix.Mueller at kip.uni-heidelberg.de
>     <mailto:Felix.Mueller at kip.uni-heidelberg.de>"
>     >>> <Felix.Mueller at kip.uni-heidelberg.de
>     <mailto:Felix.Mueller at kip.uni-heidelberg.de>>
>     >>>
>     >>>
>     >>>
>     >>> Dear Rivet experts,
>     >>>
>     >>> I'm currently implementing the Rivet routine for the inclusive
>     jet cross
>     >>> section measurement at s = 2.76 TeV (ATLAS_2013_I1228693). This
>     analysis
>     >>> also contains the ratio to the measurement at s = 7 TeV from
>     2010. The
>     >>> data for both, the cross section and the ratio is available on
>     HepData
>     >>> (http://hepdata.cedar.ac.uk/view/ins1228693).
>     >>>
>     >>> While the implementation of the cross section at one CM energy
>     is easy
>     >>> and straight forward, I'm wondering how the ratio between the two CM
>     >>> energies can be done. Does Rivet offer a general method to
>     combine two
>     >>> datasets? Or must this combination of different CM energies
>     happen in a
>     >>> post-processing step, outside Rivet?
>     >>>
>     >>> Thanks a lot!
>     >>> Cheers, Felix
>     >>>
>     >>>
>     >>
>     >
> 
> 
>     --
>     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