FA-69059 / Tide and marine navigation tables / Member archive

High and low water extraction: Double high water keeps the later peak regardless of height · case 04

The lower of two high waters is reported.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Input [h, dt, minr]: equally spaced heights every dt minutes. Interior extrema (plateaus collapse to their midpoint time) are candidates; series endpoints never are. A candidate of the same type as the last accepted event replaces it only if more extreme; otherwise a candidate whose height differs from the last accepted event by less than minr is ignored. Return [[type, minutes, height], ...].

Why this case matters

Tide tables and passage plans turn published predictions into go/no-go decisions about depth, clearance and timing.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
high and low water extraction [[0.5, 2.0, 4.8, 4.7, 4.75, 3.0, 1.0, 0.8, 1.5], 30, 0.2]	`[["HW", 120.0, 4.75], ["LW", 210.0, 0.8]]`	`[["HW", 60.0, 4.8], ["LW", 210.0, 0.8]]`	Failed

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