Add an option to TrackingTruthAccumulator to save a collection of the initial interactions

[mark-grimes]

Adds an option, off by default, for TrackingTruthAccumulator to create a TrackingVertex collection that represents the initial interaction in each signal and pileup event. This is primarily for fast timing studies.
Note that the collection does not have any links to the daughter particles in a corresponding TrackingParticle collection.

Usually the information added is a duplicate subset of what's in the other TrackingVertex collection(s), but there is no selection applied on this new collection. For the other collection(s), one of the daughters/granddaughters of the vertex needs to pass the TrackingParticle selection criteria or the vertex won't be added.

If switched on the new collection adds approximately 182120 bytes/event uncompressed, 31235 bytes/event compressed.

[mark-grimes]

please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

A new Pull Request was created by @mark-grimes (Mark Grimes) for CMSSW_6_2_X_SLHC.

Add an option to TrackingTruthAccumulator to save a collection of the initial interactions

It involves the following packages:

FastSimulation/Configuration
SimGeneral/MixingModule
SimGeneral/TrackingAnalysis

@ssekmen, @nclopezo, @lveldere, @civanch, @mdhildreth, @cmsbuild can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @battibass, @makortel, @wmtan, @abbiendi, @GiacomoSguazzoni, @rovere, @VinInn, @appeltel, @jhgoh, @matt-komm, @cerati, @trocino, @dgulhan this is something you requested to watch as well.
You can sign-off by replying to this message having '+1' in the first line of your reply.
You can reject by replying to this message having '-1' in the first line of your reply.
If you are a L2 or a release manager you can ask for tests by saying 'please test' in the first line of a comment.
@fratnikov, @mark-grimes you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[cmsbuild]

+1
Tested at: 1345037
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-8975/7431/summary.html

[lveldere]

+1

[mark-grimes]

merge