Fix lostmidfrac in track MVA selection

[makortel]

This PR fixes a small bug in the track MVA selection: in the MVA training, the so-called lostmidfrac (=nlost/(nvalid+nlost)) is correctly calculated in floating point, but in the MVA application side the fraction is calculated in integers (effectively leading the fraction to be always 0).

Below are MTV plots for 1000 events of ttbar+35PU in 810pre16 for

• phase0 https://mkortela.web.cern.ch/mkortela/tracking/validation/CMSSW_8_1_0_pre16_phase0_fixMVA/
• phase1 https://mkortela.web.cern.ch/mkortela/tracking/validation/CMSSW_8_1_0_pre16_phase1_fixMVA/

The main effect is a small (~2 % in phase0, ~1 % in phase1) decrease in the fake rates.

Tested in 8_1_0_pre16, expecting changes described above in phase0 and phase1 workflows, no change expected in phase2 (as MVA selection is not used there yet).

@rovere @VinInn

[makortel]

@cmsbuild, please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/17084/console Started: 2016/12/16 14:50

[cmsbuild]

A new Pull Request was created by @makortel (Matti Kortelainen) for CMSSW_9_0_X.

It involves the following packages:

RecoTracker/FinalTrackSelectors

@cmsbuild, @cvuosalo, @slava77, @davidlange6 can you please review it and eventually sign? Thanks.
@ghellwig, @felicepantaleo, @GiacomoSguazzoni, @rovere, @VinInn, @mschrode, @gpetruc, @dgulhan this is something you requested to watch as well.
@slava77, @smuzaffar you are the release manager for this.

cms-bot commands are listed here #13028

[cmsbuild]

+1
Tested at: 21fac34
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17057/17084/summary.html

[cmsbuild]

Comparison job queued.

[makortel]

type bugfix

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17057/17084/summary.html

[slava77]

+1

for #17057 21fac34

• change is as described, effectively enabling the use of trk.numberOfLostHits() / (trk.numberOfValidHits() + trk.numberOfLostHits()) in the MVA track selections
• jenkins tests pass and comparisons show small changes in track-related variables
• supplied MTV plots for phase-0 show particularly visible decrease in fakes in lowPtTriplet and pixelPair steps

- local tests with more samples show similar behavior in tracking variables and little visible effect downstream - "HIP"-affected data processing apparently has some significant increase in efficiency, the largest is in PXF2 (the plots are from wf 136.761_RunJetHT2016E LS91, closer to the beginning of the fill with PU~35); the total number of tracks here goes down as well.

- ttbar PU35 25202 wflow shows no significant change in CPU

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_0_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @slava77, @davidlange6, @smuzaffar

[davidlange6]

+1