Backport of #27988 (Truncate pt of PackedCandidate)

[rappoccio]

Backport of changes from #27988

PR description:

In response to #27374, truncating pt of PackedCandidate in case the 32 bit representation is beyond the 16-bit max (represented by the "minifloat" as inf, as per that standard requirement here). This was giving problems downstream when the 16-bit "infinity" was widened to 32 bits and became inaccurate.

if this PR is a backport please specify the original PR:

Original PR is #27988

[cmsbuild]

A new Pull Request was created by @rappoccio for CMSSW_10_6_X.

It involves the following packages:

DataFormats/PatCandidates

@perrotta, @cmsbuild, @santocch, @slava77 can you please review it and eventually sign? Thanks.
@gouskos, @hatakeyamak, @rovere, @cbernet, @gpetruc, @peruzzim this is something you requested to watch as well.
@davidlange6, @slava77, @fabiocos you are the release manager for this.

cms-bot commands are listed here

[perrotta]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/2601/console Started: 2019/09/20 23:54

[cmsbuild]

+1
Tested at: 33bf3a3
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-9f418a/2601/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-9f418a/2601/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 2 differences found in the comparisons
• DQMHistoTests: Total files compared: 33
• DQMHistoTests: Total histograms compared: 3210961
• DQMHistoTests: Total failures: 2
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3210625
• DQMHistoTests: Total skipped: 334
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 32 files compared)
• Checked 137 log files, 14 edm output root files, 33 DQM output files

[perrotta]

+1

• Identical backport of Truncate pt of PackedCandidate #27988, now merged in the master
• The fix replaces nan's in miniAOD outputs with some overflow value for nonphysically monster energy jets (Pt> 65 TeV) in PackedCandidate, thus avoiding possible crashes in the code that tries to access them.
• Jenkins tests pass and show no differences for non pathological events

[santocch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_10_6_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_11_0_X is complete. This pull request will now be reviewed by the release team before it's merged. @davidlange6, @slava77, @smuzaffar, @fabiocos (and backports should be raised in the release meeting by the corresponding L2)

[fabiocos]

+1

it looks safe to merge the backport even without waiting for next validation round, it is a protection truncating the pt value for cases that are anyway pathological