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Pathfinding Academy

Table of Contents

A complete index of every lesson — from foundational graph search to state-of-the-art multi-agent coordination. Lessons marked Available are ready to explore; the rest are coming soon.

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I

Part I

Single Agent Search

Core techniques for navigating a single agent through space

§3

Heuristics

Differential Heuristics (DH)

Select a few landmark nodes and precompute all-pairs distances to them. Use the triangle inequality to derive tight lower bounds at query time.

Soon
Compressed Path Databases (CPD)

A precomputed lookup table of optimal first moves, compressed to stay in memory. Enables near-perfect heuristics at low overhead.

Soon
FastMap Heuristic (FM)

Embeds the graph into Euclidean space and uses the embedding distance as a heuristic — fast to compute and compact to store.

Soon
II

Part II

Advanced Search Algorithms

Symmetry-breaking, anytime search, and temporal planning

§6

Jump Point Search

Jump Point Search

Eliminates symmetrically equivalent paths on uniform-cost grids by jumping over uninformative intermediate nodes.

Soon
Modern Jump Point Search

A cleaned-up reformulation of JPS with improved pruning rules and clearer termination conditions.

Soon
JPS+

Adds offline preprocessing to JPS so jump points can be identified in O(1) during online search.

Soon
JPS-3D

Extends jump point search to three-dimensional grid environments with 26-connected neighbours.

Soon
Rectilinear JPS

Adapts JPS for grids where only the four cardinal moves are permitted — no diagonals.

Soon
§7

Temporal Planning

Why Time is Hard

An intuition-first introduction to planning with time: why the state space explodes and what techniques tame it.

Soon
Time-Expanded A* (TXA*)

Runs A* on a time-expanded graph where each node encodes both position and timestamp, enabling exact temporal planning.

Soon
Safe Interval Path Planning (SIPP)

Plans efficiently around dynamic obstacles by computing safe time intervals at each cell and treating them as graph nodes.

Soon
III

Part III

Multi-Agent Pathfinding

Coordinating multiple agents to avoid collisions and reach their goals

§9

Optimal MAPF

Intro to MAPF

What is multi-agent pathfinding? Learn the formal definition, cost models, and why MAPF is computationally hard in general.

Soon
Prioritised Planning

Assign a priority order and plan each agent in sequence, treating higher-priority agents as moving obstacles.

Soon
Centralised A* (CA*)

Searches the joint configuration space of all agents simultaneously. Optimal, but exponential in the number of agents.

Soon
Operator Decomposition (OD)

Interleaves individual agent moves within the joint search to reduce the effective branching factor significantly.

Soon
Conflict-Based Search (CBS)

A two-level search: find individual plans, detect collisions, add constraints, and re-plan. Optimal and widely used in practice.

Soon
§10

Advanced MAPF

Enhanced Conflict-Based Search (ECBS)

An anytime variant of CBS that uses focal search to quickly find bounded-suboptimal solutions for large instances.

Soon
Priority Based Search (PBS)

Dynamically assigns priorities during search rather than fixing them upfront, achieving better completeness than naïve prioritised planning.

Soon
§11

State of the Art

Large Neighbourhood Search (LNS)

Iteratively destroys and repairs subsets of agent paths to escape local optima — scales to hundreds of agents.

Soon
Lazy Constraint Addition (LaCam)

A lazy approach that adds collision constraints only when needed, enabling extremely fast solution construction at scale.

Soon
IV

Part IV

External Resources

Benchmarks, visualisers, trackers, and competitions from the broader pathfinding community.

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