Small update of FastPV sequence - backport 72X

Backport in 72X of https://github.com/cms-sw/cmssw/pull/5667
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Small updates of the FastPrimaryVertex code and JetVertexChecker, presented at TSG meeting:
https://indico.cern.ch/event/338610/contribution/1/1/material/slides/0.pdf

In both Producer is possible to maintaing the "old" method, with the options:
 - "newMethod" in JetVertexChecker
 - "m_ptWeighting" in FastPrimaryVertexWithWeightsProducer


Thanks Slava,
I've updated the code and re-tested it.


On 10/03/2014 02:39 PM, Slava Krutelyov wrote:
>
> In 
> RecoPixelVertexing/PixelVertexFinding/src/FastPrimaryVertexWithWeightsProducer.cc:
>
> > @@ -360,6 +369,7 @@ FastPrimaryVertexWithWeightsProducer::produce(edm::Event& iEvent, const edm::Eve
> >  	        	//calculate the final weight
> >  			weight=	 m_EC_weight*(weight_dPhi) ;    	
> >  	        }
> > +		if(m_ptWeighting)	weight=weight*(pt-m_ptWeighting_parameter)/(40-m_ptWeighting_parameter); // a jetPt=40 doesn't change weight
>
> why is |40-m_ptWeighting_parameter| to be recomputed all the time .. 
> I'd even suggest to define this |40-m_ptWeighting_parameter| as the 
> ptWeighting_parameter
>
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