Backport to 12_3_X of Patatrack pixel-reco updates (pT-clamping in vertex sorting + stabilized Fishbone)

[missirol]

backport of #37281
backport of #37398

PR description:

I open the backport of #37281 and #37398 to 12_3_X as per TSG's request (see #37281 (comment); cc: @silviodonato @Martin-Grunewald).

Those PRs change the outputs of the HLT pixel reconstruction, and TSG would like to have these updates in 12_3_X (release cycle to be used at HLT at the start of Run 3).

Below, a copy of the description of the original PRs by @VinInn.

Description of #37281 ("Patatrack: introduce pt-clamping in vertex sorting, add #tracks in track SOA"):

This PR introduces some long standing improvements in Patatrack that can be useful to POG and PAG using directly SOA products.

1. Track Pt-clamping is introduced in vertex sorting.
   This is supposed to mitigate the effect of spurious tracks with large pt due to miss-measurement, resolution or inaccurate calibration/alignment.

The effect has been tested in Z->tau-tau events that are supposed to be among those who most suffer from signal-vertex miss-identification.
The effect is small if not negligible. see: http://innocent.home.cern.ch/innocent/RelVal/ztt_clamp/plots_selectedPixelVertices/pvtagging.pdf
where we compare clamping at 20, 75 (the default) and 1000 GeV.
This is not unexpected given the resolution of HP quadruplets, those used to build vertices, that reaches ~30% at ~70 GeV.
It may be different with initial calibrations or large inefficiency.

Results for ttbar can be found in
http://innocent.home.cern.ch/innocent/RelVal/gpuMTVclamp/plots_selectedPixelVertices/pvtagging.pdf

2. The number of tracks is stored in the track SOA.
   This should make the use of the SOA more user-friendly.

Default has changed, so expect small regressions.

Excerpt of the description of #37398 ("Stabilize Fishbone"):

The fishbone has been made deterministic and order independent.
The main change is (of course) removing the break in the combinatorial double loop.

results:
Timing: negligible effect.

MTV: slight increase of duplicate (as more fishbone cells are created) for Loose tracks. no effect on HP
http://innocent.home.cern.ch/innocent/RelVal/gpuMTVstableFB/

detailed comparison of reproducibility
[..]
In particular with this PR (no break) comparing 10 events at track level
NO difference in HP quadruplets, only one HP triplet differs.
the rest are loose triplets (and a couple of loose quadruplets)
REMINDER:
loose tracks are in the collection ONLY to be used for seeding or for algorithms that perform some sort of pre-cleaning
(often a simple association to trimmed-vertices is enough).

Making the various ambiguity solvers deterministic and order independent will be much harder and costly

PR validation:

Relies on the validation done for the original PRs.

If this PR is a backport, please specify the original PR and why you need to backport that PR:

#37281
#37398

[cmsbuild]

A new Pull Request was created by @missirol (Marino Missiroli) for CMSSW_12_3_X.

It involves the following packages:

• CUDADataFormats/Track (heterogeneous, reconstruction)
• RecoPixelVertexing/PixelTrackFitting (reconstruction)
• RecoPixelVertexing/PixelTriplets (reconstruction)
• RecoPixelVertexing/PixelVertexFinding (reconstruction)

@makortel, @slava77, @clacaputo, @cmsbuild, @fwyzard, @jpata can you please review it and eventually sign? Thanks.
@felicepantaleo, @GiacomoSguazzoni, @JanFSchulte, @rovere, @VinInn, @mmusich, @mtosi, @dgulhan this is something you requested to watch as well.
@perrotta, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

• Backported from Patatrack: introduce pt-clamping in vertex sorting, add #tracks in track SOA #37281

[VinInn]

I though #37398 was more urgent (and could have been backported together)

[missirol]

Indeed, I was waiting for #37398 to be signed, before asking if TSG wanted a backport of it (most likely, yes). I can then append that backport here, if it helps.

[fwyzard]

+heterogeneous

[fwyzard]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-df3cc3/23621/summary.html
COMMIT: 6a039d8
CMSSW: CMSSW_12_3_X_2022-04-02-1100/slc7_amd64_gcc10
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/37444/23621/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 49
• DQMHistoTests: Total histograms compared: 3697381
• DQMHistoTests: Total failures: 2
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3697357
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 48 files compared)
• Checked 204 log files, 45 edm output root files, 49 DQM output files
• TriggerResults: no differences found

[clacaputo]

test parameters:

• enable_test = gpu

[clacaputo]

@cmsbuild please test

[cmsbuild]

Pull request #37444 was updated. @makortel, @slava77, @clacaputo, @cmsbuild, @fwyzard, @jpata can you please check and sign again.

[missirol]

urgent

Repurposed this PR to a backport of both #37281 and #37398, as I assume TSG also wants the latter backported in time for 12_3_0 (@silviodonato and @fwyzard will correct me if that's not the case).

("urgent" here means "in time for 12_3_0")

[missirol]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-df3cc3/23623/summary.html
COMMIT: 3c15c2f
CMSSW: CMSSW_12_3_X_2022-04-02-1100/slc7_amd64_gcc10
Additional Tests: GPU
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/37444/23623/install.sh to create a dev area with all the needed externals and cmssw changes.

GPU Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 24 differences found in the comparisons
• DQMHistoTests: Total files compared: 4
• DQMHistoTests: Total histograms compared: 19874
• DQMHistoTests: Total failures: 3601
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 16273
• DQMHistoTests: Total skipped: 0
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 3 files compared)
• Checked 12 log files, 9 edm output root files, 4 DQM output files
• TriggerResults: no differences found

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 49
• DQMHistoTests: Total histograms compared: 3697381
• DQMHistoTests: Total failures: 3841
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3693518
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 48 files compared)
• Checked 204 log files, 45 edm output root files, 49 DQM output files
• TriggerResults: found differences in 1 / 48 workflows

[clacaputo]

+reconstruction

• backport of Patatrack: introduce pt-clamping in vertex sorting, add #tracks in track SOA #37281 + Stabilize Fishbone #37398
• minor reco differences in 11634.506, in line with the PR content

[missirol]

Kind ping for the signature of @cms-sw/heterogeneous-l2 (this PR had already been signed, but then I added the backport of #37398).

[fwyzard]

+heterogeneous

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_12_3_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_12_4_X is complete. This pull request will now be reviewed by the release team before it's merged. @perrotta, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[qliphy]

+1