Improve profile computation memory efficiency by schroedtert · Pull Request #525 · PedestrianDynamics/PedPy

schroedtert · 2026-03-28T14:29:54Z

Profile functions (compute_density_profile, compute_speed_profile, compute_profiles) no longer require pre-computed grid intersections. When grid_intersections_area is not provided, intersections are computed per frame internally, avoiding the allocation of the full (grid_cells × pedestrians) matrix.

Add _compute_frame_grid_intersection helper for single-frame intersection
Change _compute_grid_polygon_intersection to process frame-by-frame using NumPy instead of a single broadcast
Make grid_intersections_area optional in compute_density_profile and compute_speed_profile (on-the-fly when omitted)
Simplify compute_profiles to delegate to compute_density_profile and compute_speed_profile per frame with shared intersection
Update user guide to use the simpler API without compute_grid_cell_polygon_intersection_area

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Pull request overview

Updates PedPy’s profile computation APIs to avoid requiring a precomputed full grid×pedestrian intersection matrix, enabling per-frame intersection computation to reduce peak memory usage for large datasets.

Changes:

Adds _compute_frame_grid_intersection and updates profile methods to compute intersections per frame when grid_intersections_area is omitted.
Refactors compute_profiles to iterate frame-by-frame and share per-frame intersections between density and speed computations.
Updates plotting title handling, notebooks/user guide examples, and pre-commit tooling (including nbstripout metadata stripping).

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
`pedpy/plotting/plotting.py`	Ensures plot titles aren’t overwritten by `plot_walkable_area` defaults.
`pedpy/methods/profile_calculator.py`	Implements per-frame intersection computation and updates profile APIs/logic accordingly.
`notebooks/user_guide.ipynb`	Updates examples to use the simplified API without precomputing intersections.
`notebooks/getting_started.ipynb`	Strips notebook kernel metadata (via nbstripout configuration).
`notebooks/fundamental_diagram_at_measurement_line.ipynb`	Strips notebook kernel metadata.
`notebooks/fundamental_diagram.ipynb`	Strips notebook kernel metadata.
`.pre-commit-config.yaml`	Bumps tool versions and configures nbstripout to remove kernel/language metadata.

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Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 6 comments.

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chraibi · 2026-04-07T20:40:55Z

Benchmark results

Ran scripts/bench_profiles.py --frames 300 --peds 150 --repeats 1 (45k rows, 20×20 grid) on main vs this branch:

Metric	`main`	this branch
`compute_profiles` time	24.9s	15.1s
`compute_profiles` peak memory	1238 MB	7.3 MB
Precomputation time	12.6s	7.7s
`density_profile` (precomputed)	0.12s	0.10s

Peak memory drops from 1.2 GB → 7 MB (~170× reduction) with a ~40% speed improvement on the combined path. The per-frame approach trades some compute overhead for dramatically lower memory usage, which was the goal.

Benchmark script added in scripts/bench_profiles.py for reproducibility.

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Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated no new comments.

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Adapt pre-commit config to keep the tags, jupyter and id metadata of the notebooks.

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Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

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Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

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Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

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Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

Profile functions (compute_density_profile, compute_speed_profile, compute_profiles) no longer require pre-computed grid intersections. When grid_intersections_area is not provided, intersections are computed per frame internally, avoiding the allocation of the full (grid_cells × pedestrians) matrix. - Add _compute_frame_grid_intersection helper for single-frame intersection - Change _compute_grid_polygon_intersection to process frame-by-frame using NumPy instead of a single broadcast - Make grid_intersections_area optional in compute_density_profile and compute_speed_profile (on-the-fly when omitted) - Simplify compute_profiles to delegate to _compute_density_for_frame and _compute_speed_for_frame per frame with shared intersection - Extract _compute_density_for_frame and _compute_speed_for_frame as single-dispatch helpers; compute_density_profile and compute_speed_profile also delegate here, eliminating duplicated method branches - Move frame-invariant quantities (bounds, grid centers) out of the per-frame loop to avoid redundant recomputation - Update user guide to use the simpler API without compute_grid_cell_polygon_intersection_area

codecov · 2026-05-08T20:27:25Z

Codecov Report

❌ Patch coverage is 93.16239% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.84%. Comparing base (d362055) to head (877ab17).

Files with missing lines	Patch %	Lines
pedpy/methods/profile_calculator.py	93.16%	8 Missing ⚠️

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schroedtert added the profiles Anything related to computing profiles label Mar 28, 2026

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schroedtert added the usability Anything increasing the usablity label Mar 28, 2026

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chraibi marked this pull request as ready for review April 7, 2026 20:41

chraibi requested review from JuleAdrian and Copilot April 7, 2026 20:44

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chraibi force-pushed the improve-large-traj-profiles branch from ecdceba to a2ca5be Compare April 7, 2026 20:58

chraibi removed the request for review from JuleAdrian April 8, 2026 09:43

schroedtert marked this pull request as draft April 9, 2026 06:16

schroedtert added this to the v1.5.0 milestone May 3, 2026

schroedtert force-pushed the improve-large-traj-profiles branch 2 times, most recently from 203a77e to 214d006 Compare May 4, 2026 19:47

Adapt pre-commit config

f70f08d

Adapt pre-commit config to keep the tags, jupyter and id metadata of the notebooks.

schroedtert force-pushed the improve-large-traj-profiles branch 2 times, most recently from 79f420b to ebe7a36 Compare May 4, 2026 20:16

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schroedtert force-pushed the improve-large-traj-profiles branch from ebe7a36 to c84a5c7 Compare May 4, 2026 20:36

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schroedtert force-pushed the improve-large-traj-profiles branch from c84a5c7 to 5b164dd Compare May 8, 2026 19:45

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schroedtert force-pushed the improve-large-traj-profiles branch 3 times, most recently from 1993bb7 to 0848ce9 Compare May 8, 2026 20:01

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schroedtert force-pushed the improve-large-traj-profiles branch from 0848ce9 to e20b685 Compare May 8, 2026 20:13

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schroedtert force-pushed the improve-large-traj-profiles branch from e20b685 to 877ab17 Compare May 8, 2026 20:20

schroedtert marked this pull request as ready for review May 8, 2026 21:10

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schroedtert commented Mar 28, 2026

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chraibi commented Apr 7, 2026

Benchmark results

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codecov Bot commented May 8, 2026

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