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Merge mapf_post into mapf and align types - #37

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Merge mapf_post into mapf and align types#37
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arjo/feat/merge-mapf-post

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@arjo129 arjo129 commented Mar 6, 2026 •
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Implemented feature

#29

Implementation description

This PR merges the mapf_post functionality into the mapf crate, as tracked in issue #29. This consolidation simplifies the codebase and aligns the types between the core MAPF utilities and the post-processing algorithms used for robust plan execution.

Motivation

Previously, mapf_post existed as a separate utility or was part of an external experimental repository. Merging it into mapf allows for tighter integration with the base traits and types of the multi-agent planning framework, facilitating a more seamless transition from planning to execution-ready semantic plans.

Key Changes

  1. Core post Module:

    • Introduced mapf/src/post/mod.rs containing the implementation of the mapf_post algorithm based on the approach described in Hoenig et al., 2019 (https://whoenig.github.io/publications/2019_RA-L_Hoenig.pdf).
    • This algorithm converts time-discretized MAPF results into dependency-based SemanticPlans, which are more resilient to timing delays during robot execution.

  2. Semantic Planning & Following:

    • Added SemanticPlan and SemanticWaypoint types to represent agent-level dependencies.
    • Implemented WaypointFollower to help estimate an agent's progress along its assigned trajectory and identify the next safe waypoint.

  3. Collision Detection:

    • Integrated parry2d-f64 for high-fidelity collision checking between agent footprints during trajectory execution. This replaces simpler time-based checks with geometric sweeps.

  4. Spatial Allocation:

    • Added mapf/src/post/spatial_allocation/mod.rs, which provides a Grid2D and AllocationField system.
    • This system enables the reservation of spatial zones (dynamic safety areas) based on the semantic plan's dependencies, ensuring robots maintain safe separation even when they deviate from the original time-schedule.

  5. Crate Updates:

    • Updated mapf to the Rust 2024 edition.
    • Added new dependencies: parry2d, petgraph, bresenham, rand, and csv to support the new post-processing features.
    • Updated nalgebra to version 0.32.

Implementation Details

  • mapf_post identifies "Type 1" (sequential) and "Type 2" (collision-avoidance) dependencies between waypoints.
  • AllocationField implements tie-breaking rules for spatial reservations, including leader-follower hierarchies and intersection-aware prioritization.
  • WaypointFollower uses projection onto trajectory segments to remain robust against localization jitter or minor navigation errors.

Verification

  • Added unit tests in mapf/src/post/mod.rs covering:
    • WaypointFollower logic.
    • SemanticPlan waypoint and dependency management.
    • Collision detection between moving shapes.
    • Core mapf_post algorithm on a simple cross-junction scenario.
    • Violation checking and claim dictionary generation.

GenAI Use

We follow OSRA's policy on GenAI tools

Note the original library doesnt use gen-ai I used gen-ai to see if it could merge the two libraries and reconcile APIs.

  • I used a GenAI tool in this PR.
  • I did not use GenAI

Generated-by: Gemini-cli

@mxgrey mxgrey added this to PMC Board Mar 6, 2026
@github-project-automation github-project-automation Bot moved this to Inbox in PMC Board Mar 6, 2026
@xiyuoh xiyuoh moved this from Inbox to In Progress in PMC Board Mar 10, 2026
@arjo129
arjo129 force-pushed the arjo/feat/merge-mapf-post branch from 0d9939c to 26e2496 Compare March 19, 2026 05:00
arjo129
arjo129 commented Mar 19, 2026
View reviewed changes
Comment thread mapf/src/negotiation/scenario.rs Outdated
Comment thread mapf/src/post/spatial_allocation/mod.rs
Comment thread mapf/src/negotiation/mod.rs
Comment thread mapf/src/negotiation/mod.rs
arjo129 added 10 commits March 20, 2026 09:11
@arjo129
Merge mapf_post into mapf and align types
081cac7 
Generated-by: Gemini-CLI

Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
Integrate Scenario with solver and post-processor
2d88e90 
This adds solve(), derive_mapf_result(), and derive_semantic_plan()
to the Scenario struct for tighter integration between MAPF solving
and trajectory derivation.

Generated-by: Gemini-CLI
Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
Include moving obstacles as agents in MapfResult for traffic dependen…
d3a5f32 
…cies

This allows obstacles in a Scenario to be represented as agents in the
MAPFPost output, enabling traffic dependency analysis for moving
objects.

Generated-by: Gemini-CLI
Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
Downgrade mapf to Rust 2021 for broader compatibility
093e807 
- Changed edition to 2021 in mapf/Cargo.toml
- Refactored 'let chains' in post module to nested 'if let' blocks
- Removed unused petgraph import
- Updated formatting across multiple files to match 2021 edition

Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
Fix formatting
6a192f6 
Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
undo unessecary changes
ecb1afc 
Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
Remove dead slop code
e4af8fb 
Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
Refactor agent ID handling and remove unnecessary mutability
c473b14 
- Move agent ID assignment from negotiate to derive_mapf_result
- Remove id_to_name field from Scenario struct
- Change negotiate and Scenario::solve to take shared references
- Add agent_name_to_id to MapfResult and SemanticPlan
- Add get_agent_id helper to SemanticPlan

Generated-by: Gemini CLI
Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
Make MapfResult private to prvent confusion
71cfa00 
Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
Implement Grid2D constructor from Scenario
a001f0e 
- Add Grid2D::from_scenario and From<&Scenario> for Grid2D
- Correctly calculate grid dimensions and occupancy from Scenario data
- Update allocate_trajectory to use dynamic grid dimensions
- Add unit test for from_scenario constructor

Generated-by: Gemini CLI
Signed-off-by: Gemini CLI <gemini-cli@google.com>
Signed-off-by: Arjo Chakravarty <arjoc@intrinsic.ai>
@arjo129
arjo129 force-pushed the arjo/feat/merge-mapf-post branch from 1282d90 to a001f0e Compare March 20, 2026 09:11
@arjo129 arjo129 linked an issue Apr 8, 2026 that may be closed by this pull request
[Feature request]: Add support for extracting semantic plan #29
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@mxgrey mxgrey moved this from In Progress to Blocked in PMC Board Jun 16, 2026
@uday-kalyan-s

uday-kalyan-s commented Aug 3, 2026

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Proposal to switch to spatial partitioning for broad-phase collision detection

Hi! I'm Uday. I had previously submitted a GSoC proposal to work on this PR, and I'm still very interested in contributing to it.

As part of that proposal, I planned to implement the MAPF-POST improvements from P3GASUS, which includes replacing the current broad-phase collision detection with a more efficient spatial partitioning approach.

Some references I found useful while working on this:

One of the earlier blockers was supporting heterogeneous robots (robots with different sizes). That issue has since been addressed by replacing KD-trees with AABB trees in the graph creation pipeline. I implemented and benchmarked this approach here:

I believe this work provides a solid foundation for implementing the same idea here.

Would it be okay if I started by using this branch in my fork to develop the changes, and later opened a PR targeting the merge-mapf-post branch?

@uday-kalyan-s

uday-kalyan-s commented Aug 3, 2026

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@arjo129 @mxgrey

@arjo129

arjo129 commented Aug 4, 2026

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Hi @uday-kalyan-s upstream (https://github.com/arjo129/mapf_post) already has a broadphase based acceleration. I would encourage you to look at it and implement the same on this branch.

@uday-kalyan-s

uday-kalyan-s commented Aug 4, 2026

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Right yes I found the implementation of the AABB tree there. extremely sorry for my earlier comment. I will get to working on this branch then.

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[Feature request]: Add support for extracting semantic plan

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@arjo129 @uday-kalyan-s @mxgrey @xiyuoh