[Rivet] multipying two histos?

[Andy Buckley]

On 01/05/10 13:31, Lars Sonnenschein wrote:
> Hello Andy, (all),
> I have now implemented and filled with sense the histos with the 
> CDSsim/Idealsim correction factors into the CDF_1994_S2952106 analysis. 
> But when I try to multiply it seems not to work, the output histos don't 
> change. I use:
> 
>  AIDA::IHistogramFactory& hf = histogramFactory();
>  hf.multiply("/_histJet3eta", *_histJet3eta, *_histEta3Corr);
>  
> where the _histEta3Corr is the histo which contains the correction 
> factors. I have written them out to check that they are filled reasonably.
> What I want to do is:
> _histJet3eta = _histJet3eta * _histEta3Corr;
> 
> I have tried a couple of other things, unfortunatey without success.
> If somebody has an idea how to get this working.

Hi Lars,

You should check the AIDA/LWH classes for info on how the
HistogramFactory works. Of course it produces output in the AIDA path
specified as the first argument string, so if you were expecting
"/_histJet3eta" to somehow be translated into the variable _histJet3eta,
that certainly won't work. Possibly you need to make a temporary
histogram and then write the result of the multiplication into the
correct output path. My guess is that your current AIDA output contains
an extra histogram called "/_histJet3eta", with the correct values in it.

Cheers,
Andy

-- 
Dr Andy Buckley
SUPA Advanced Research Fellow
Particle Physics Experiment Group, University of Edinburgh