geodesic_heat — MATH geometry op

• Data kinds: mesh → table

• Call: import fullseye as fs; fs.ledger.geodesic_heat(vertices, faces=None, source=0, *, t: 'float | None' = None) -> 'dict' (to call the implementation directly, import mathgeometry; mathgeometry.geodesic_heat(vertices, faces=None, source=0, *, t: 'float | None' = None) -> 'dict'; from the registry, opsmath.get("geodesic_heat"))

Usage

> This operator's description has not been translated yet. The original text follows as it is.

熱法による曲面上の測地距離(Crane et al. 2013)。`source` は頂点番号(または番号の列、既定は頂点 0)。

メッシュは `(vertices, faces)` でも mesh の組 1 つでもよい。

1) (M − tL) u = δ を 1 ステップ解く(熱を時間 t だけ広げる、t の既定 = 平均辺長²)

2) 各三角形で X = −∇u / |∇u|(熱が来た向きと逆 = 距離が増える向き)

3) L φ = ∇·X を解き、source で 0 になるようずらす

門: 平面メッシュでユークリッド距離、球面で大円距離 Rθ に、細かくするほど近づく。

返り値 `{"distance", "t"}`。

Family-wide input contract (fail-closed)

Every mathops op validates its input before computing (nothing slips through silently):

• **complex input raises ValueError** — coercing to float64 silently discards the imaginary part (numpy only emits a ComplexWarning and returns a plausible-looking wrong real number). State .real/.imag/abs() explicitly, or use complexops, which handles complex data.

• **masked arrays with masked elements raise ValueError** — the implicit conversion that peels off the mask and uses the raw values underneath is refused. Say explicitly whether to fill or to drop.

• **NaN/Inf raises ValueError on every input** (refused with the count stated — it propagates through the whole result).

• Shapes are strict: 1-D and 2-D are never implicitly promoted or broadcast (a matrix in a vector slot, or a vector in a matrix slot, raises ValueError; reshape explicitly).

• Size cap: ops that take a matrix, and the stat_histogram bins, raise ValueError beyond mathops.MAX_ELEMENTS (2^26 ≈ 67 million elements).

Detailed usage guide

• math_metrology family guide

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)

• geometry_tour — py -3.11 examples/geometry_tour.py

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

dynsys_poincare_section · dwt_inverse · chebyshev_eval_nd

Same category (geometry)

mesh_euler_characteristic · angle_defect · delaunay_triangulate · geodesic_heat_grid · mesh_torus · nurbs_curve · nurbs_circle · nurbs_surface


*Provenance: mathgeometry.py — MATH 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.