FA-69215 / Tide and marine navigation tables / Member archive

Standard port tidal curve: Neap curve is interpolated with the spring slope · case 05

Neap-weighted heights drift from the neap curve between table hours.

Member previewVariant 5 · 3 implementations · 7 checks per implementation

Case contract

Input [hrel, hw, lw, sr, nr, hours, fs, fn]: hours ascending, fs/fn spring and neap curve factors. Outside [hours[0],hours[-1]] return None. Factors are linearly interpolated in time on each curve, then blended with k=clamp((hw-lw-nr)/(sr-nr),0,1) as fn+(fs-fn)*k. Height = lw + f*(hw-lw), rounded to 3 decimals.

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
standard port tidal curve [2.0, 4.0, 1.0, 4.2, 1.8, [-5.5, -4.5, -3.5, -2.5, -1.5, -0.5, 0.5, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5], [0.0, 0.08, 0.25, 0.5, 0.75, 0.93, 1.0, 0.92, 0.72, 0.47, 0.24, 0.07, 0.0], [0.0, 0.12, 0.32, 0.55, 0.78, 0.94, 1.0, 0.95, 0.8, 0.6, 0.38, 0.15, 0.02]]	`3.505`	`3.542`	Failed

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