FAILURE MAP
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FA-68866 / Tide and marine navigation tables / Open access

Harmonic tide prediction: Greenwich phase lag is added to the argument · case 01

Predicted high waters arrive early by twice the phase lag.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The constituent phase lag g is added instead of subtracted in the argument.

THE FAILURE

The constituent phase lag g is added instead of subtracted in the argument.

Unsuccessful approach: Dropping V0 and u to keep only speed*t-g fixes the lag sign but loses the astronomical argument.

Case contract

Input [t_minutes, z0, constituents]; each constituent is [H metres, g phase lag deg, speed deg/hour, nodal factor f, nodal phase u deg, equilibrium argument V0 deg]. Height above chart datum is z0 + sum f*H*cos(V0+u+speed*t_hours-g). Return rounded to 4 decimals.

Why this case matters

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

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
    t,z0,cons=x
    hours=t/60
    h=z0
    for H,g,spd,f,u,v0 in cons:
        arg=(v0+u+spd*hours+g)%360
        h+=f*H*math.cos(math.radians(arg))
    return round(h,4)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('harmonic tide prediction [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.8751), ('harmonic tide prediction [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 2.3585), ('harmonic tide prediction [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.2364), ('harmonic tide prediction [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9476), ('harmonic tide prediction [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9225), ('harmonic tide prediction [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.6113), ('harmonic tide prediction [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.3542)], [('harmonic tide prediction [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 2.3585), ('harmonic tide prediction [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9476), ('harmonic tide prediction [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9225), ('harmonic tide prediction [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.6113), ('harmonic tide prediction [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.3542), ('harmonic tide prediction [0, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [0, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 3.2733), ('harmonic tide prediction [200, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [200, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 4.1537)], [('harmonic tide prediction [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.2364), ('harmonic tide prediction [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.3542), ('harmonic tide prediction [0, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [0, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 3.2733), ('harmonic tide prediction [200, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [200, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 4.1537), ('harmonic tide prediction [745, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [745, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 3.2709), ('harmonic tide prediction [90, 0.0, [[1.0, 0.0, 30.0, 1.0, 0.0, 0.0]]]', [90, 0.0, [[1.0, 0.0, 30.0, 1.0, 0.0, 0.0]]], 0.7071), ('harmonic tide prediction [0, 1.5, []]', [0, 1.5, []], 1.5)], [('harmonic tide prediction [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9476), ('harmonic tide prediction [745, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [745, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 3.2709), ('harmonic tide prediction [90, 0.0, [[1.0, 0.0, 30.0, 1.0, 0.0, 0.0]]]', [90, 0.0, [[1.0, 0.0, 30.0, 1.0, 0.0, 0.0]]], 0.7071), ('harmonic tide prediction [0, 1.5, []]', [0, 1.5, []], 1.5), ('harmonic tide prediction [0, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [0, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 0.2259), ('harmonic tide prediction [300, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [300, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 1.6646), ('harmonic tide prediction [610, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [610, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 0.6277)], [('harmonic tide prediction [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9225), ('harmonic tide prediction [0, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [0, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 0.2259), ('harmonic tide prediction [300, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [300, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 1.6646), ('harmonic tide prediction [610, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [610, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 0.6277), ('harmonic tide prediction [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.8751), ('harmonic tide prediction [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 2.3585), ('harmonic tide prediction [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.2364)]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
harmonic tide prediction [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]0.96661.8751Failed
harmonic tide prediction [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]0.74782.3585Failed
harmonic tide prediction [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]1.38573.2364Failed
harmonic tide prediction [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]3.61931.9476Failed
harmonic tide prediction [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]0.76431.9225Failed
harmonic tide prediction [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]1.89993.6113Failed
harmonic tide prediction [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]1.36191.3542Failed

SHA-256 / 4e3720ef596f389e52dc47410defa9566e10886f5ce581e7c8062464de2154e1

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
    t,z0,cons=x
    hours=t/60
    h=z0
    for H,g,spd,f,u,v0 in cons:
        arg=(spd*hours-g)%360
        h+=f*H*math.cos(math.radians(arg))
    return round(h,4)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('harmonic tide prediction [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.8751), ('harmonic tide prediction [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 2.3585), ('harmonic tide prediction [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.2364), ('harmonic tide prediction [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9476), ('harmonic tide prediction [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9225), ('harmonic tide prediction [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.6113), ('harmonic tide prediction [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.3542)], [('harmonic tide prediction [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 2.3585), ('harmonic tide prediction [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9476), ('harmonic tide prediction [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9225), ('harmonic tide prediction [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.6113), ('harmonic tide prediction [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.3542), ('harmonic tide prediction [0, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [0, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 3.2733), ('harmonic tide prediction [200, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [200, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 4.1537)], [('harmonic tide prediction [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.2364), ('harmonic tide prediction [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.3542), ('harmonic tide prediction [0, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [0, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 3.2733), ('harmonic tide prediction [200, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [200, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 4.1537), ('harmonic tide prediction [745, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [745, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 3.2709), ('harmonic tide prediction [90, 0.0, [[1.0, 0.0, 30.0, 1.0, 0.0, 0.0]]]', [90, 0.0, [[1.0, 0.0, 30.0, 1.0, 0.0, 0.0]]], 0.7071), ('harmonic tide prediction [0, 1.5, []]', [0, 1.5, []], 1.5)], [('harmonic tide prediction [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9476), ('harmonic tide prediction [745, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]]', [745, 3.0, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0]]], 3.2709), ('harmonic tide prediction [90, 0.0, [[1.0, 0.0, 30.0, 1.0, 0.0, 0.0]]]', [90, 0.0, [[1.0, 0.0, 30.0, 1.0, 0.0, 0.0]]], 0.7071), ('harmonic tide prediction [0, 1.5, []]', [0, 1.5, []], 1.5), ('harmonic tide prediction [0, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [0, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 0.2259), ('harmonic tide prediction [300, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [300, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 1.6646), ('harmonic tide prediction [610, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [610, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 0.6277)], [('harmonic tide prediction [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.9225), ('harmonic tide prediction [0, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [0, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 0.2259), ('harmonic tide prediction [300, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [300, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 1.6646), ('harmonic tide prediction [610, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]]', [610, 1.0, [[0.8, 270.0, 28.9841042, 0.97, 4.0, 90.0]]], 0.6277), ('harmonic tide prediction [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 1.8751), ('harmonic tide prediction [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 2.3585), ('harmonic tide prediction [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]', [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]], 3.2364)]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
harmonic tide prediction [0, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]1.3111.8751Failed
harmonic tide prediction [45, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]1.92372.3585Failed
harmonic tide prediction [180, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]3.60353.2364Failed
harmonic tide prediction [371, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]3.13481.9476Failed
harmonic tide prediction [720, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]1.12311.9225Failed
harmonic tide prediction [1000, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]3.43563.6113Failed
harmonic tide prediction [1440, 2.1, [[1.2, 110.0, 28.9841042, 1.02, -2.1, 35.0], [0.4, 150.0, 30.0, 1.0, 0.0, 0.0], [0.25, 95.0, 15.0410686, 1.1, 8.5, 210.0]]]0.87821.3542Failed

SHA-256 / 0836cf366d3b10ec2e1b058889dd5b398deccc9bc3eb1c9ac5fe53f82b594a89

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 7 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

A deterministic toy model with stipulated rules and constants; not certified hydrographic software or a substitute for official tide tables. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:48:06.386826+00:00.

Case digest / ff9f10cea23398c8c1cad26f22edf1a8c876e29e6d407b40865d4cc8fa9b6a29