Vectorize data pre-processing when training track embeddings in LST

[alexandertuna]

PR description:

This PR numpyfies a few data operations in the notebook which derives track embeddings for improved duplicate removal in LST. The data operations are notably faster with numpy operations than with python for-loops.

Followup to: #48249

PR validation:

I ran the notebook locally and on a large computer, and it is indeed faster. I checked all events by hand to confirm the numpy operations give identical results as the python operations. Chatgpt and gemini also approve of the approach.

cc @GNiendorf @slava77

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-48335/45215

[cmsbuild]

A new Pull Request was created by @alexandertuna for master.

It involves the following packages:

• RecoTracker/LSTCore (reconstruction)

@cmsbuild, @jfernan2, @mandrenguyen can you please review it and eventually sign? Thanks.
@GiacomoSguazzoni, @VinInn, @VourMa, @dgulhan, @felicepantaleo, @gpetruc, @missirol, @mmusich, @mtosi, @rovere this is something you requested to watch as well.
@antoniovilela, @mandrenguyen, @rappoccio, @sextonkennedy you are the release manager for this.

cms-bot commands are listed here

[jfernan2]

please test

[jfernan2]

+1
Standalone changes

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs after it passes the integration tests. This pull request will now be reviewed by the release team before it's merged. @rappoccio, @sextonkennedy, @antoniovilela, @mandrenguyen (and backports should be raised in the release meeting by the corresponding L2)

[cmsbuild]

+1

Size: This PR adds an extra 224KB to repository
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-95c34d/46782/summary.html
COMMIT: bdf1c8f
CMSSW: CMSSW_15_1_X_2025-06-16-2300/el8_amd64_gcc12
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/48335/46782/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially removed 1 lines from the logs
• Reco comparison results: 6 differences found in the comparisons
• DQMHistoTests: Total files compared: 52
• DQMHistoTests: Total histograms compared: 4279628
• DQMHistoTests: Total failures: 140
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 4279468
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 51 files compared)
• Checked 223 log files, 194 edm output root files, 52 DQM output files
• TriggerResults: no differences found

[mandrenguyen]

+1