refactor: faster computation for binary search

[CarloVarni]

Faster binary search then std::lower_bound

[github-actions]

📊: Physics performance monitoring for 61922bc

Full contents

physmon summary

• ✅ CKF truth_smeared
• ✅ IVF truth_smeared
• ✅ AMVF truth_smeared
• ✅ Track Summary CKF truth_smeared
• ✅ Seeding truth_estimated
• ✅ CKF truth_estimated
• ✅ IVF truth_estimated
• ✅ AMVF truth_estimated
• ✅ Track Summary CKF truth_estimated
• ✅ Seeding seeded
• ✅ CKF seeded
• ✅ IVF seeded
• ✅ AMVF seeded
• ✅ AMVF (+grid seeder) seeded
• ✅ Track Summary CKF seeded
• ✅ Seeding orthogonal
• ✅ CKF orthogonal
• ✅ IVF orthogonal
• ✅ AMVF orthogonal
• ✅ Track Summary CKF orthogonal
• ✅ Ambisolver seeded
• ✅ Ambisolver orthogonal
• ✅ Seeding ttbar
• ✅ CKF ttbar
• ✅ Ambisolver
• ✅ Track Summary CKF ttbar
• ✅ AMVF ttbar
• ✅ AMVF (+grid seeder) ttbar
• ✅ Truth tracking (GSF)
• ✅ Truth tracking
• ✅ Truth tracking (GX2F)
• ✅ Particles fatras
• ✅ Particles geant4

[andiwand]

@CarloVarni do you have some numbers / plots on how much faster this is?

Would it make sense to put this in some utility function for broader use or would this kill the performance?

[CarloVarni]

Hi @andiwand , it's the red line. This is the average execution time as a function of the size of the collection N. Test performed locally using a vector of doubles

Btw, that piece of code is called around 18 times for each bin in the grid as of now. I am not sure how this will translate in the overall execution time on a tt-bar pu 200

Concerning utility function, I'm afraid this computation is too specific to this use case (and probably this is where it gets the perf boost). The general solution is the std::lower_bound that will use pointers and allow for a custom comparator

[andiwand]

shall we leave this note for future developers?

otherwise looks good to go!

[acts-project-service]

🔴 Athena integration test results [b9251ca]

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