diabolo op• Data kinds: signal × signal × scalar → table
• Call: import fullseye as fs; fs.ledger.diabolo_spheroid(p_left, p_right, string_length: 'float') -> 'dict' (to call the implementation directly, import diabolo; diabolo.diabolo_spheroid(p_left, p_right, string_length: 'float') -> 'dict'; from the registry, opsdrive.get("diabolo_spheroid"))
The 2 stick tips (foci) and the string length → auxiliary spheroid: a = l/2, c = |x_L − x_R|/2, b = √(a² − c²) (the correct form of Eq. 1).
★The original (1b) is b = √(a² − |x_L − x_R|/2), a difference between a length and the square of a length, so the dimensions do not match. Plugging in the paper's real-device dimensions (string 1.45 m, stick spacing 1.10 m) makes the radicand negative (NaN). It is rewritten in the form of the ellipse identity a² = b² + c² (the public implementation also writes it with squares). The original value is kept in b_paper_literal. The original preamble swaps the names, "semi-major axis b and semi-minor axis a" (a = l/2 is the semi-major axis); we follow the formula.
Returns {"center", "axis"(x_L − x_R の単位ベクトル), "a", "b", "c", "b_paper_literal"}. Raises ValueError: spacing ≥ string, sticks coincide, non-finite input.
• 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.
• poc_diabolo_model_and_vision — py -3.11 examples/poc_diabolo_model_and_vision.py
table as input)course_layout · course_occupancy · course_contains · world_build · world_camera · world_move · lidar_scan · rss_longitudinal_same
diabolo)diabolo_params · spheroid_closest · diabolo_dynamics_step · diabolo_simulate · diabolo_state_sequence · diabolo_throw_catch_truth · string_tension_static · string_tension_from_sag
*Provenance: diabolo.py — DRIVE 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.