piv_velocity_gradient — PIV `field` op

• Data kinds: flow2d → table

• Call: import fullseye as fs; fs.ledger.piv_velocity_gradient(flow, spacing=1.0) (to call the implementation directly, import pivops; pivops.piv_velocity_gradient(flow, spacing=1.0); from the registry, opspiv.get("piv_velocity_gradient"))

Usage

Returns the components of the velocity-gradient tensor together with the quantities derived from it.

Vorticity, divergence, Q-criterion, swirling strength and strain rate all derive from the same 4 derivatives, so they are gathered here to avoid recomputing the gradient 4 times. The individual ops (piv_vorticity etc.) can be used on their own, but if you need several, use this.

Returns:

dict: dudx / dudy / dvdx / dvdy (each (h, w)),

vorticity / divergence / q / swirl / strain_rate,

spacing.

Detailed usage guide

• piv_displacement 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)

• piv_field_analysis_tour — py -3.11 examples/piv_field_analysis_tour.py

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

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Same category (`field`)

piv_vorticity · piv_divergence · piv_flow_magnitude · piv_to_velocity · piv_q_criterion · piv_swirling_strength · piv_strain_rate

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

piv_velocity_gradient — PIV field op