angle_to_matrix — REPRCONV algebra op

• Data kinds: angle → matrix

• Call: import fullseye as fs; fs.ledger.angle_to_matrix(angle) (to call the implementation directly, import reprconv; reprconv.angle_to_matrix(angle); from the registry, opsreprconv.get("angle_to_matrix"))

Usage

Angle [deg] → the rotation matrix (3,3) about the z-axis. The exit from angle.

angle_to_matrix(90) sends axis 1 (y) to axis 2 (x), and axis 2 (x) to −axis 1 (−y) (R @ [0,1,0] = [0,0,1], R @ [0,0,1] = [0,-1,0], measured). It is the same [[c,-s],[s,c]] orientation as the 2-D rot_scale_to_matrix (axis 0 → axis 1) placed on axes (1, 2), and atan2(R[2,1], R[1,1]) of matrix_to_angle also round-trips in this orientation. That it is in degrees and which axis it rotates towards is the entire content of this paragraph. Passing radians raises no exception; you simply get a matrix rotated by only 1/57.3 of the intended angle.

Args:

angle: degrees.

Returns:

(3, 3) float64, orthogonal matrix with determinant 1.

Raises:

ValueError: not a scalar / non-finite.

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)

• representation_roundtrip — py -3.11 examples/representation_roundtrip.py

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

matrix_to_descriptor · matrix_to_angle · matrix_to_rot_scale

Same category (algebra)

matrix_to_angle · rot_scale_to_matrix · matrix_to_rot_scale · shift_to_vector · vector_to_shift · cscalar_to_polar · polar_to_cscalar · countrate_to_counts


*Provenance: reprconv.py — REPRCONV 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.