FA-68876 / Tide and marine navigation tables / Open access

Harmonic tide prediction: Degree argument is passed to cosine as radians · case 01

Predictions oscillate erratically with no semidiurnal pattern.

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

ROOT CAUSE

The argument is kept in degrees but passed straight to math.cos.

THE FAILURE

The argument is kept in degrees but passed straight to math.cos.

Unsuccessful approach: Dividing by 360 instead of 180 halves every phase.

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(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 fixture	Actual	Expected	Outcome
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]]]	`2.8018`	`1.8751`	Failed
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]]]	`1.0195`	`2.3585`	Failed
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]]]	`1.1206`	`3.2364`	Failed
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]]]	`1.5792`	`1.9476`	Failed
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]]]	`2.5983`	`1.9225`	Failed
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]]]	`1.4797`	`3.6113`	Failed
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]]]	`2.6049`	`1.3542`	Failed

SHA-256 / e3dd8dcad38e12335d140d2675ef0e9db358373a16e3ac8b792a77c571c85c16

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=(v0+u+spd*hours-g)%360
        h+=f*H*math.cos(arg*math.pi/360)
    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 fixture	Actual	Expected	Outcome
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]]]	`1.1694`	`1.8751`	Failed
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]]]	`0.9449`	`2.3585`	Failed
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]]]	`3.0003`	`3.2364`	Failed
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]]]	`3.1641`	`1.9476`	Failed
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]]]	`0.8828`	`1.9225`	Failed
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]]]	`3.1012`	`3.6113`	Failed
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]]]	`1.35`	`1.3542`	Failed

SHA-256 / d74f9f5f6a163a0d5a2ee34f067d1e5174024cc173f57c96372afcff5d29fea3

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.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

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 / 20f31846533e1b1c8089d8435a974eef5792c2badff8712c39d19e31869c1070