dynsys op• Data kinds: none → flow2d (an op determined by its arguments alone — it takes no image or data input)
• Call: import fullseye as fs; fs.ledger.ode_vector_field_grid(system='rossler', params=None, bounds=(-10.0, 10.0, -10.0, 10.0), shape=(64, 64), plane='xy', offset=0.0) (to call the implementation directly, import mathops; mathops.ode_vector_field_grid(system='rossler', params=None, bounds=(-10.0, 10.0, -10.0, 10.0), shape=(64, 64), plane='xy', offset=0.0); from the registry, opsmath.get("ode_vector_field_grid"))
Sample a named field on a grid — a flow2d the existing viewers take.
Returns (2, H, W) with components (dy, dx) — the library's flow2d layout — so the existing flow2d viewers render it with no new drawing code: piv_flow_to_rgbimage (colour wheel), piv_flow_magnitude and piv_line_integral_convolution (texture along the flow), piv_quiver (arrows) and piv_streamline_image / piv_streamlines (evenly spaced streamlines). (★2026-10-03: this docstring used to name "quiver, streamlines, flow_magnitude" before any quiver or streamline op existed; they were added the same day. fs.flow_magnitude takes two components, not a flow2d array.) For a 3-D system, *plane* picks the slice (xy / xz / yz) and *offset* fixes the third coordinate.
★Why this earns its place: it is the bridge that keeps this family from growing its own renderer. The vectors are the same _dyn_derivative the integrator uses, so what you see is what gets integrated.
★The layout is channel-first, not the (H, W, 2) that reads more naturally here: flow2d is an existing type with an existing predicate and existing consumers, and a row that declares flow2d while returning the transpose is a type lie the fuzzer catches (it did —— 2026-09-23). Row 0 is the top (the image convention), so the vertical component is negated to match what the viewer draws.
Raises ValueError: unknown system or plane; a grid over the cap; non-finite bounds; a degenerate window.
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).
• 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_what_a_picture_cannot_check — py -3.11 examples/poc_what_a_picture_cannot_check.py
flow2d as input)—
dynsys)ode_flow_states · dynsys_poincare_section · dynsys_lyapunov_spectrum · dynsys_bifurcation_map · dynsys_correlation_dimension
*Provenance: mathops.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.