[BeamSpot] fit 1D projections of PV distribution to get initial values for 3D fit parameters

[rmanzoni]

back porting #10780

[slava77]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

A new Pull Request was created by @rmanzoni (Riccardo Manzoni) for CMSSW_7_5_X.

[BeamSpot] fit 1D projections of PV distribution to get initial values for 3D fit parameters

It involves the following packages:

RecoVertex/BeamSpotProducer

@diguida, @cvuosalo, @cerminar, @cmsbuild, @slava77, @mmusich can you please review it and eventually sign? Thanks.
@makortel, @GiacomoSguazzoni, @rovere, @VinInn, @cerati, @dgulhan this is something you requested to watch as well.
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[cmsbuild]

+1
Tested at: 4d421de
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10781/7323/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10781/7323/summary.html

[cvuosalo]

+1

For #10781 4d421de

Changing the initial values of the primary vertex fit. The 76X version of this PR, #10780, has already been approved by Reco.

The code changes are satisfactory. Jenkins tests against baseline CMSSW_7_5_X_2015-08-14-1100 show very small changes in PV fit results, but none of these differences are significant. See #10780 for an example plot of the small changes in the fit results.

[diguida]

+1
for 4d421de

The correspondent version in 76X #10780 has already been approved by AlCa.

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_5_X IBs once checked with relvals in the development release cycle of CMSSW (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @smuzaffar

[davidlange6]

+1