[Rivet] dividing histos in Rivet

[Hannes Jung]

Hi Andy

thanks a lot.
This example did help indeed.
BTW, is there any reason, why I have to book still a AIDA histo, to get the LWH histos in the output, or am I doing something weird ?
Anyway, at the end I got the histos..

Cheers
Hannes

On 23.03.2011, at 10:50, Andy Buckley wrote:

> On 22/03/11 20:54, Hannes Jung wrote:
>> dear riveties
>> 
>> I was wondering, whether there is a simple way to divide two histograms in rivet/aida ?
>> Just couldn't find it in the manual
> 
> Hi Hannes,
> 
> To do divisions or other histogram combinations you need to go via the
> HistogramFactory, and mix and match histogram paths with histogram
> pointers... it's just a bit cumbersome. To avoid getting duplicate
> numerator and denominator histograms in the output, I tend to use raw
> (non-persistent) LWH histograms for those. You'll find an example (well,
> a few examples) in the src/Analyses/MC_GENERIC.cc source file.
> 
> This round-about way of combining histograms is an AIDA monstrosity: a
> good example of how not to design a histogramming interface! Leif may
> know about a neater way to do this with the LWH histograms, whose
> interface is less awkward than the AIDA ones (i.e. LWH::Histogram1D
> rather than AIDA::IHistogram1D). It's all going to be nicer in Rivet
> version 2.0.
> 
> Hope that helps,
> Andy
> 
> -- 
> Dr Andy Buckley
> SUPA Advanced Research Fellow
> Particle Physics Experiment Group, University of Edinburgh
> 
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
> 

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Hannes Jung 
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