FA-69084 / Tide and marine navigation tables / Member archive

Tidal height window: A window already open at the first sample is lost · case 04

When the tide is already high enough at the start, the first window is omitted or truncated.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Input [ts, hs, req]: sample times (minutes) and heights. Return the list of [start, end] intervals where height>=req, with crossing times linearly interpolated and rounded conservatively inward (start up, end down, 1e-9 tolerance); windows that vanish after rounding are dropped. A window open at the first sample starts at ts[0]; one still open at the end closes at ts[-1].

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
tidal height window [[0, 60, 120, 180], [3.0, 1.0, 1.0, 3.0], 1.5]	`[[135, 180]]`	`[[0, 45], [135, 180]]`	Failed

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