[Rivet] dividing histograms

[Andy Buckley]

Emily Nurse wrote:
> Hi all,
> 
> What's the best way to divide two histograms in the finalize() method  
> of an analysis routine?
> James and I looked into it and could only see the  histogramFactory 
> ().divide() function. But this means that you can't book the  
> histogram in the normal way using auto-booking etc. The other way is  
> to use an AIDA::IDataPointSet* instead of a histogram and to set the  
> contents by hand in the finalize method.
> Neither of these are very elegant so I was wondering if there is  
> another way, and whether this will be easier with YODA?

I think that with AIDA in Rivet you really need to do the latter (using
the DPS). Otherwise you'll get stuck with the same problem that hit
Lars, in that the bin widths will get applied as scaling factors when
the histo tree is written out. You woudn't notice that affecting the
shape if the bins are of equal width, but it would affect the normalisation.

And, yes, it will be better with YODA... and if it isn't, you've got me
to complain at ;)

Andy

-- 
Dr Andy Buckley
Institute for Particle Physics Phenomenology
Durham University
0191 3343798 | 0191 3732613 | www.insectnation.org