obstacle_fit_doublet — DRIVE `swarmflow` op

• Data kinds: table → table

• Call: import fullseye as fs; fs.ledger.obstacle_fit_doublet(field, speed=None, upstream_only: 'bool' = False, exclude_margin: 'float' = 1.25, min_explained: 'float' = 0.5, min_radius=None) -> 'dict' (to call the implementation directly, import swarmflow; swarmflow.obstacle_fit_doublet(field, speed=None, upstream_only: 'bool' = False, exclude_margin: 'float' = 1.25, min_explained: 'float' = 0.5, min_radius=None) -> 'dict'; from the registry, opsdrive.get("obstacle_fit_doublet"))

Usage

Fits the potential flow around a cylinder u − i v = U (1 − R²/(z − z_c)²) to the velocity field (implementation 2, 2-D nonlinear least squares).

> The detailed description below is the original text — the summary and the headings are translated.

未知数は (x_c, y_c, R², U)。出発点は 2 つ: stagnation_from_centerline と、格子の節点を中心の候補にした粗い探索(U を固定すると模型は R² について 1 次なので閉形式で解ける)。説明できる割合の大きい方を採る。円の exclude_margin 倍より内側の格子は使わない(格子へ移す核が壁をまたいで速さを均すため)—— 推定し直して 3 回回す。upstream_only なら衝突点より上流(x < x_c − R)の格子だけで当てはめる(「当たる前に」分かるか)。

判定: 一様流だけの模型(u, v が定数)の残差 RSS₀ に対して、円柱の模型で減った割合 1 − RSS₁/RSS₀(乱れのうち円柱で説明できる割合)が min_explained 以上、半径が min_radius(既定 = 格子の間隔 2 つ)以上、中心が場の中 —— の 3 つで detected。否定の判定(障害物なし)はこの割合が小さいことで出る。

★半径の下限は解像の限界: swarm_field_from_tracks の格子は個体の間隔 s ごとなので、既定では R < 2s の障害物を「ある」と言わない。拒否が正当なことは実測で確かめた(一様に撒いた粒子、R = 0.6 m: R/s ≈ 5 で中心・半径とも 2 % 以内、R/s ≈ 2.5 で 5 % 以内、R/s ≈ 1.2 で半径が 48 % 小さく出る)。

Returns:

dict: center・radius・speed・stagnation・explained・detected・n_used・rms_residual

(m/s)・rms_null(m/s)。

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_swarm_obstacle_from_flow — py -3.11 examples/poc_swarm_obstacle_from_flow.py

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

course_layout · course_occupancy · course_contains · world_build · world_camera · world_move · lidar_scan · rss_longitudinal_same

Same category (`swarmflow`)

sph_kernel · sph_density_pressure · swarm_simulate · swarm_render_overhead · swarm_field_from_tracks · swarm_field_from_piv · potential_flow_cylinder · velocity_deficit_map

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

obstacle_fit_doublet — DRIVE swarmflow op