quack: strided leaves and an in-place aperture sweep; probe: HHTL-ordered vs random access

[AdaWorldAPI]

#1290 lowered a facet aperture to a Range under the ordering witness. Every other aperture, though, swept the two extracted semantic u64 planes. This PR adds the in-place form of that sweep, so a caller that holds only NodeRow bytes can use it.

Leaves. Cmp::{EqU32Strided, NeU32Strided, MatchFacetStrided} each lower one-to-one to the mask-risc predicate of the same name, which realises through the ndarray::simd strided kernels. A facet stored inside a wider record is queried where it sits.

Aperture sweep. Filter::aperture_facet_strided(witnessed, lane_col, classid_col, tiers_col, aperture) reads two views over the same bytes:

• EqU32Strided on the classid at +0;
• MatchFacetStrided on the 12 tier bytes at +4.

Each leg is included only when the aperture cares about that part. The bound-or-sweep decision is factored out of aperture_facet and shared, so a witnessed prefix becomes the same Range on either sweep.

An aperture that cares about only part of the classid returns None. It has no in-place spelling, because the strided classid reader is an equality and no strided u32 ternary match exists. Such an aperture still lowers through aperture_facet.

Contract. SemanticAperture::{pattern, care} accessors.

Tests (strided_leaf_tests) run at a 40-byte stride and at the real 512-byte stride, with junk bytes around every facet:

• The three leaves select exactly what a plain reading of the stored bytes selects.
• On 80 random apertures with and without holes, the in-place sweep, the plane sweep and the aperture itself agree. Anti-vacuity counts require that holes and non-trivial cuts both occur.
• A witnessed prefix produces an identical (Filter, ApertureLowering) on either path.
• A partial classid care is refused, and the plane path still answers it correctly.

Disable runs (each went red, then back to green once restored):

disable	tests that went red
leaf pattern/care swapped	2
tier bytes read at +0	1
classid leg dropped	2
partial classid accepted	1

Checks: cargo test -p lance-graph-quack passes. The contract ordered_lane tests pass. clippy --all-targets -D warnings is clean on both crates. The workspace-excluded crates that use quack (lance-graph-sap, d-diamond-1-probe, r2il-mask-abi-probe) contain no exhaustive match on Cmp; I grepped them, they were not built.

Board: entries/2026-09-25-aperture-prefix-lowers-to-range.md has a new "in-place sweep" section, and its OPEN list is updated.

Also: HHTL-ordered vs random access (examples/hhtl_order_probe.rs)

This answers the "HHTL-ordered access has not been measured" caveat left by #1290. The query is the same vertical partial mask. Only the visit order changes: random, ascending address order, or 256-row blocks visited in random order with rows in order inside each block. Latency is a pointer chase, 3 runs.

members, 16-byte records	random	ordered	clustered
32k rows, packed	7.8–8.7 ns	3.2–3.3 ns	3.2–3.3 ns
one tile (1 MB)	13.1–14.6 ns	3.2–3.3 ns	3.3–3.5 ns
four tiles (4 MB)	28.5–30.5 ns	3.2–3.4 ns	3.4 ns
64 tiles (64 MB)	144–172 ns	3.8–4.0 ns	4.4–4.9 ns
256k scattered over 4M (1 in 16)	133–161 ns	94–99 ns	114–121 ns

What the numbers say:

• Ordered access over the packed key lane is flat at ~3–4 ns per node up to 64 MB, because the prefetcher streams it. The ~12 / ~25 ns regimes are the cost of random order, not of the working set.
• Only order within a subtree matters: jumping between blocks in random order costs almost nothing extra.
• Sparsity of 1 member in 16 rows defeats the prefetcher.
• At the 512-byte in-place stride, ordering only roughly halves the cost: 32k rows go from 65–125 ns to 22–24 ns.

Board: entries/2026-09-25-hhtl-ordered-access.md (new).

🤖 Generated with Claude Code

https://claude.ai/code/session_01GXUahz73MZxtxWcfpHp9dG

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Generated by Claude Code

Summary by CodeRabbit

• New Features
  • Added in-place facet-aperture filtering for strided data, including class identifiers and tier values. Partial class-identifier matching continues to use plane-based filtering.
  • Added access to the normalized pattern and care-mask facets used by semantic apertures.
• Documentation
  • Updated performance measurements comparing ordered, clustered, and random data access across different data sizes. The results now account for all members in each case.

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📝 Walkthrough

Walkthrough

The change adds public aperture accessors, strided comparison predicates, and an in-place facet-aperture sweep. It also changes the ordered-access probe to visit at least all members in its latency and throughput paths, and updates its reported measurements.

Changes

Strided facet aperture

Layer / File(s)	Summary
Aperture accessors and predicate variants crates/lance-graph-contract/src/facet.rs, crates/lance-graph-quack/src/lib.rs	SemanticAperture exposes its pattern and care facets. Cmp adds strided equality, inequality, and 12-byte facet-match variants.
In-place aperture sweep and validation crates/lance-graph-quack/src/lib.rs, .claude/board/entries/2026-09-25-aperture-prefix-lowers-to-range.md	Filter::aperture_facet_strided rejects partial classid care, compares cared fields, and uses the shared witnessed bound-or-sweep path. pred_of maps the new variants to mask-risc predicates. Tests compare strided predicates and sweeps with direct reads and semantic-plane results at 40-byte and 512-byte strides. The board entry describes witnessed prefixes and the partial-care limitation.

Ordered-access probe

Layer / File(s)	Summary
Full-member access probe and measurements crates/lance-graph-mask-risc/examples/hhtl_order_probe.rs, .claude/board/entries/2026-09-25-hhtl-ordered-access.md, .claude/board/entries/README.md	The probe uses the greater of Q and member count for latency traversal and throughput queries. Its documentation and board entry update measurements and describe the former visit cap. The README adds the board entry to its index.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant Caller
  participant Filter
  participant aperture_with
  Caller->>Filter: Call aperture_facet_strided with aperture and lanes
  Filter->>aperture_with: Select witnessed bound or sweep
  Filter-->>Caller: Return filter and lowering

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Merge Risk: ⚪ Minimal · up to f738f

The aperture sweep and full-member probe are ready to merge after normal checks; no actionable issue was identified.

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Check name	Status	Explanation	Resolution
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✅ Passed checks (4 passed)

Check name	Status	Explanation
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Title check	✅ Passed	The title accurately identifies both main changes: strided quack predicates with an in-place aperture sweep, and the HHTL ordered-versus-random access probe.

Full details: Docstring Coverage

Explanation

Docstring coverage is 60.61% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 33 functions across 3 files. (1 skipped: 1 unsupported.)

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_{I, rabbit, check the tier bytes in flight
Strided predicates keep each comparison tight
A witnessed prefix finds its range
Partial classid care takes the plane
The probe counts each member on its way
And fresh results mark the day}

_{Comment @coderabbitai help to get the list of available commands.}

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Inline comments:
In `@crates/lance-graph-mask-risc/examples/hhtl_order_probe.rs`:
- Line 48: Update the `latency` and `throughput` paths in the probe to visit
every member of each case-sized ordered cycle, rather than using the fixed
`Q`-sized prefix. Derive the visit count and query sequence from the cycle
length, then rerun the probe and update the 64 MB measurements and conclusion.

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