Refactor subspace storage and handling

[stephenswat]

This commit refactors the subspace representation to become more compact, and also adds additional member functions to elegantly model some of the operations performed on the projection matrix in the Kálmán filter code. Specifically, it packs the indices using a single bit field rather than an array of integers. Furthermore, it allows for the subspace to store signed projections (used for line surfaces) as well as invalid projections (used for 1D measurements).

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
8.8% Duplication on New Code

See analysis details on SonarQube Cloud

[stephenswat]

Physics performance summary

Here is a summary of the physics performance effects of this PR. Command used:

traccc_seeding_example_cuda --input-directory=/data/Acts/odd-simulations-20240506/geant4_ttbar_mu200 --digitization-file=geometries/odd/odd-digi-geometric-config.json --conditions-file=geometries/odd/odd-digi-geometric-config.json --detector-file=geometries/odd/odd-detray_geometry_detray.json --grid-file=geometries/odd/odd-detray_surface_grids_detray.json --material-file=geometries/odd/odd-detray_material_detray.json --input-events=10 --use-acts-geom-source=on --check-performance --truth-finding-min-track-candidates=5 --truth-finding-min-pt=1.0 --truth-finding-min-z=-150 --truth-finding-max-z=150 --truth-finding-max-r=10 --seed-matching-ratio=0.99 --track-matching-ratio=0.5 --track-candidates-range=5:100 --seedfinder-vertex-range=-150:150

Seeding performance

Total number of seeds went from 298341 to 298340 (-0.0%)

Seeding plots

Track finding performance

Total number of found tracks went from 50211 to 50206 (-0.0%)

Finding plots

Track fitting performance

Fitting plots

Seeding to track finding relative performance

Seeding to track finding plots

Note

This is an automated message produced on the explicit request of a human being.

[stephenswat]

Performance summary

Here is a summary of the performance effects of this PR:

Graphical

Tabular

Kernel	Reciprocal Throughput			Parallelism
	bd18c46	0b7bb10	Delta	bd18c46	0b7bb10
propagate_to_next_surface	5.80 ms	5.80 ms	0.0%	4.33	4.33
find_tracks	1.76 ms	2.10 ms	19.4%	1.82	1.60
count_doublets	829.83 μs	820.67 μs	-1.1%	1.61	1.61
ccl_kernel	591.91 μs	591.54 μs	-0.1%	1.71	1.71
count_triplets	567.94 μs	567.75 μs	-0.0%	1.02	1.02
find_doublets	535.00 μs	537.89 μs	0.5%	3.08	3.08
Thrust::sort	378.90 μs	378.89 μs	-0.0%	7.32	7.32
find_triplets	169.54 μs	169.58 μs	0.0%	1.31	1.32
estimate_track_params	146.55 μs	146.68 μs	0.1%	2.68	2.68
build_tracks	123.87 μs	125.04 μs	0.9%	3.71	3.72
select_seeds	59.48 μs	58.66 μs	-1.4%	1.34	1.34
populate_grid	23.86 μs	23.92 μs	0.2%	1.22	1.22
count_grid_capacities	22.13 μs	22.14 μs	0.1%	1.22	1.22
remove_duplicates	19.99 μs	20.17 μs	0.9%	25.67	25.50
fill_sorted_measurements	16.22 μs	16.31 μs	0.5%	1.13	1.13
update_triplet_weights	14.85 μs	14.89 μs	0.2%	1.27	1.27
fill_finding_propagation_sort_keys	8.76 μs	8.73 μs	-0.3%	7.75	7.76
form_spacepoints	8.39 μs	8.42 μs	0.3%	1.49	1.49
reduce_triplet_counts	5.63 μs	5.64 μs	0.2%	3.09	3.09
unknown	5.04 μs	5.03 μs	-0.1%	4.27	4.27
fill_finding_duplicate_removal_sort_keys	1.56 μs	1.56 μs	0.2%	37.97	37.89
Total	11.09 ms	11.43 ms	3.0%	3.39	3.31

Important

All metrics in this report are given as reciprocal throughput, not as wallclock runtime.

Warning

At least one kernel incurred a significant performance regression.

Note

This is an automated message produced upon the explicit request of a human being.