ticl: Optimize calculation of Trackster time

[felicepantaleo]

This PR optimizes the calculation of Trackster time in RecoHGCal/TICL/plugins/TrackstersPCA.cc by improving both code efficiency and readability.

• Key improvements include:
  • Replaced std::vector<double> with std::array<float, 3> for spatial coordinates, reducing memory overhead and enhancing computational performance.
  • Simplified the logic of the project_lc_to_pca function by directly calculating the squared distance, removing the need for extra square root operations.
  • Optimized the time correction calculation, introducing a more concise variable for the inverse of z and adjusting the logic for deltaT to improve numerical stability.
  • Removed redundant checks for used layer clusters in the loop, further simplifying the code.

Overall, these changes result in cleaner code and potentially faster execution without altering the core functionality.

@AuroraPerego fyi

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-46133/41922

[cmsbuild]

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

It involves the following packages:

• RecoHGCal/TICL (upgrade, reconstruction)

@Moanwar, @cmsbuild, @jfernan2, @mandrenguyen, @srimanob, @subirsarkar can you please review it and eventually sign? Thanks.
@apsallid, @forthommel, @hatakeyamak, @lecriste, @missirol, @rovere, @sameasy, @sobhatta, @youyingli 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

[felicepantaleo]

test parameters:

• workflow_opts= -w upgrade
• workflow = 29696.203

[felicepantaleo]

enable profiling

[felicepantaleo]

type hgcal

[felicepantaleo]

please test

[cmsbuild]

+1

Size: This PR adds an extra 20KB to repository
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d5463d/41767/summary.html
COMMIT: 9e79e19
CMSSW: CMSSW_14_2_X_2024-09-26-1100/el8_amd64_gcc12
Additional Tests: PROFILING
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/46133/41767/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: 10 differences found in the comparisons
• DQMHistoTests: Total files compared: 45
• DQMHistoTests: Total histograms compared: 3431875
• DQMHistoTests: Total failures: 6
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3431849
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 44 files compared)
• Checked 198 log files, 167 edm output root files, 45 DQM output files
• TriggerResults: no differences found

[jfernan2]

please test
Launching tests once more to get last FastTimer CPU profiling changes from:
cms-sw/cms-bot#2348
cms-sw/cms-bot#2349
cms-sw/cms-bot#2343
cms-sw/cms-bot#2344

[cmsbuild]

+1

Size: This PR adds an extra 12KB to repository
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d5463d/41850/summary.html
COMMIT: 9e79e19
CMSSW: CMSSW_14_2_X_2024-10-01-1100/el8_amd64_gcc12
Additional Tests: PROFILING
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/46133/41850/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially added 3 lines to the logs
• Reco comparison results: 20 differences found in the comparisons
• DQMHistoTests: Total files compared: 45
• DQMHistoTests: Total histograms compared: 3431875
• DQMHistoTests: Total failures: 1696
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3430159
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 44 files compared)
• Checked 198 log files, 167 edm output root files, 45 DQM output files
• TriggerResults: no differences found

[jfernan2]

@felicepantaleo I see timing reductions in many places involving Tracksters and HGCAL, thanks!
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d5463d/41850/profiling/29834.21/diff-step3_cpu.resources.json.html

[jfernan2]

+1

[Moanwar]

+Upgrade

[cmsbuild]

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

[mandrenguyen]

+1