car_dubins_path — GRAPH path op

• Data kinds: matrix → table

• Call: import fullseye as fs; fs.ledger.car_dubins_path(poses, radius=1.0, step=0.05) (to call the implementation directly, import carpath; carpath.car_dubins_path(poses, radius=1.0, step=0.05); from the registry, opsgraph.get("car_dubins_path"))

Usage

Shortest forward-only path of a car between two poses (Dubins 1957) by the six closed-form words.

poses is [[x, y, theta], [x', y', theta']] (start, goal; theta in radians, counter-clockwise from the x axis). The car turns with minimum radius radius and never reverses. Dubins proved the shortest path is one of LSL, RSR, LSR, RSL, RLR, LRL (arcs of maximal curvature and straights); each word's three segment lengths are closed-form (Shkel and Lumelsky 2001). Every candidate is verified by forward integration to the goal and discarded if it misses (fail-closed against formula slips; the count is returned as n_rejected), and the shortest survivor is the answer.

Returns word, length (metres), segments [(kind, gear, length)] (kind L/S/R, gear +1), points (N, 3) poses sampled every step metres along the path (start and goal included), candidates [(word, length)] for all verified words in increasing length, n_rejected, lower_bound (the Euclidean distance, never exceeded), radius.

Raises ValueError: poses not (2, 3) finite; radius or step not positive; no word reaches the goal (cannot happen for finite poses; reported rather than guessed).

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• poc_car_parking — py -3.11 examples/poc_car_parking.py

• poc_driving_school — py -3.11 examples/poc_driving_school.py

Ops the type connects to (they accept table as input)

graph_edge_consensus · graph_core_persistence · tree_morphometry · tree_sholl · tree_run_length

Same category (path)

car_reeds_shepp_path · car_hybrid_astar


*Provenance: carpath.py — GRAPH operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.