FA-100424 / Feature preprocessing fit scope / Member archive

Quantile bin assignment uses held-out rows while fitting · case 04

Quantile bin assignment uses held-out rows while fitting.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Train is nonempty, bins is positive. Select empirical cut values at floor(i*n/bins), capped to the final training index. Count strict greater-than cut comparisons, so equality stays in the lower bin.

Why this case matters

A small deterministic preprocessing contract makes the fit boundary and transform behavior directly inspectable.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
nondivisible rank boundary	`[0]`	`[1]`	Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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