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FA-15451 / Numerics / Open access

Exact ldl decomposition: lower factor row coverage · case 01

The exact exact ldl decomposition result violates the stated contract at lower factor row coverage.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The lower factor row coverage step uses range(j+2,n) instead of range(j+1,n).

VERIFIED REPAIR

Use range(j+1,n) at the lower factor row coverage step.

Unsuccessful approach: The partial repair range(j+1,n-1) still violates the lower factor row coverage invariant.

Case contract

Input symmetric positive definite integer matrix; return unit lower L and diagonal D as rational pairs such that A=L*D*Ltranspose.

Why this case matters

Exact discrete arithmetic with observable algorithmic state; no floating point approximation is used.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
import itertools
from fractions import Fraction
N = 1
observations = []
def solve(x):
    a=[list(map(Fraction,row)) for row in x];n=len(a);L=[[Fraction(int(i==j)) for j in range(n)] for i in range(n)];D=[Fraction(0)]*n
    for j in range(n):
     D[j]=a[j][j]-sum(L[j][k]**2*D[k] for k in range(j))
     if not D[j]:return None
     for i in range(j+2,n):
      L[i][j]=(a[i][j]-sum(L[i][k]*L[j][k]*D[k] for k in range(j)))/(D[j])
    return [[[[v.numerator,v.denominator] for v in row] for row in L],[[v.numerator,v.denominator] for v in D]]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[([[14, 2], [2, 2]], [[[[1, 1], [0, 1]], [[1, 7], [1, 1]]], [[14, 1], [12, 7]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]])], [([[11, 3], [3, 14]], [[[[1, 1], [0, 1]], [[3, 11], [1, 1]]], [[11, 1], [145, 11]]]), ([[14, -12], [-12, 14]], [[[[1, 1], [0, 1]], [[-6, 7], [1, 1]]], [[14, 1], [26, 7]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]])], [([[14, -8], [-8, 6]], [[[[1, 1], [0, 1]], [[-4, 7], [1, 1]]], [[14, 1], [10, 7]]]), ([[14, -1], [-1, 6]], [[[[1, 1], [0, 1]], [[-1, 14], [1, 1]]], [[14, 1], [83, 14]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]])], [([[14, -12], [-12, 14]], [[[[1, 1], [0, 1]], [[-6, 7], [1, 1]]], [[14, 1], [26, 7]]]), ([[19, 15], [15, 14]], [[[[1, 1], [0, 1]], [[15, 19], [1, 1]]], [[19, 1], [41, 19]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]])], [([[14, 3], [3, 11]], [[[[1, 1], [0, 1]], [[3, 14], [1, 1]]], [[14, 1], [145, 14]]]), ([[11, 6], [6, 5]], [[[[1, 1], [0, 1]], [[6, 11], [1, 1]]], [[11, 1], [19, 11]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[1, 0], [0, 19]], [[[[1, 1], [0, 1]], [[0, 1], [1, 1]]], [[1, 1], [19, 1]]]), ([[3, 2], [2, 5]], [[[[1, 1], [0, 1]], [[2, 3], [1, 1]]], [[3, 1], [11, 3]]]), ([[9, 0], [0, 1]], [[[[1, 1], [0, 1]], [[0, 1], [1, 1]]], [[9, 1], [1, 1]]]), ([[6, 5], [5, 11]], [[[[1, 1], [0, 1]], [[5, 6], [1, 1]]], [[6, 1], [41, 6]]])]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("explicit oracle %d" % i, 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
explicit oracle 0[[[[1, 1], [0, 1]], [[0, 1], [1, 1]]], [[14, 1], [2, 1]]][[[[1, 1], [0, 1]], [[1, 7], [1, 1]]], [[14, 1], [12, 7]]]Failed
explicit oracle 1[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed
explicit oracle 2[[[[1, 1], [0, 1], [0, 1], [0, 1]], [[0, 1], [1, 1], [0, 1], [0, 1]], [[3, 4], [0, 1], [1, 1], [0, 1]], [[-3, 20], [-7, 8], [0, 1], [1, 1]]], [[20, 1], [8, 1], [15, 4], [617, 40]]][[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]Failed
explicit oracle 3[[[[1, 1]]], [[5, 1]]][[[[1, 1]]], [[5, 1]]]Passed
explicit oracle 4[[[[1, 1]]], [[5, 1]]][[[[1, 1]]], [[5, 1]]]Passed
explicit oracle 5[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed
explicit oracle 6[[[[1, 1]]], [[10, 1]]][[[[1, 1]]], [[10, 1]]]Passed
explicit oracle 7[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed

SHA-256 / 51b5331c246732906f2ed363cccdc9ec6377fc4c4d7b8cd0b92330c73bc80340

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
import itertools
from fractions import Fraction
N = 1
observations = []
def solve(x):
    a=[list(map(Fraction,row)) for row in x];n=len(a);L=[[Fraction(int(i==j)) for j in range(n)] for i in range(n)];D=[Fraction(0)]*n
    for j in range(n):
     D[j]=a[j][j]-sum(L[j][k]**2*D[k] for k in range(j))
     if not D[j]:return None
     for i in range(j+1,n-1):
      L[i][j]=(a[i][j]-sum(L[i][k]*L[j][k]*D[k] for k in range(j)))/(D[j])
    return [[[[v.numerator,v.denominator] for v in row] for row in L],[[v.numerator,v.denominator] for v in D]]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[([[14, 2], [2, 2]], [[[[1, 1], [0, 1]], [[1, 7], [1, 1]]], [[14, 1], [12, 7]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]])], [([[11, 3], [3, 14]], [[[[1, 1], [0, 1]], [[3, 11], [1, 1]]], [[11, 1], [145, 11]]]), ([[14, -12], [-12, 14]], [[[[1, 1], [0, 1]], [[-6, 7], [1, 1]]], [[14, 1], [26, 7]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]])], [([[14, -8], [-8, 6]], [[[[1, 1], [0, 1]], [[-4, 7], [1, 1]]], [[14, 1], [10, 7]]]), ([[14, -1], [-1, 6]], [[[[1, 1], [0, 1]], [[-1, 14], [1, 1]]], [[14, 1], [83, 14]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]])], [([[14, -12], [-12, 14]], [[[[1, 1], [0, 1]], [[-6, 7], [1, 1]]], [[14, 1], [26, 7]]]), ([[19, 15], [15, 14]], [[[[1, 1], [0, 1]], [[15, 19], [1, 1]]], [[19, 1], [41, 19]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]])], [([[14, 3], [3, 11]], [[[[1, 1], [0, 1]], [[3, 14], [1, 1]]], [[14, 1], [145, 14]]]), ([[11, 6], [6, 5]], [[[[1, 1], [0, 1]], [[6, 11], [1, 1]]], [[11, 1], [19, 11]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[1, 0], [0, 19]], [[[[1, 1], [0, 1]], [[0, 1], [1, 1]]], [[1, 1], [19, 1]]]), ([[3, 2], [2, 5]], [[[[1, 1], [0, 1]], [[2, 3], [1, 1]]], [[3, 1], [11, 3]]]), ([[9, 0], [0, 1]], [[[[1, 1], [0, 1]], [[0, 1], [1, 1]]], [[9, 1], [1, 1]]]), ([[6, 5], [5, 11]], [[[[1, 1], [0, 1]], [[5, 6], [1, 1]]], [[6, 1], [41, 6]]])]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("explicit oracle %d" % i, 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
explicit oracle 0[[[[1, 1], [0, 1]], [[0, 1], [1, 1]]], [[14, 1], [2, 1]]][[[[1, 1], [0, 1]], [[1, 7], [1, 1]]], [[14, 1], [12, 7]]]Failed
explicit oracle 1[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed
explicit oracle 2[[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[0, 1], [0, 1], [0, 1], [1, 1]]], [[20, 1], [24, 5], [15, 8], [22, 1]]][[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]Failed
explicit oracle 3[[[[1, 1]]], [[5, 1]]][[[[1, 1]]], [[5, 1]]]Passed
explicit oracle 4[[[[1, 1]]], [[5, 1]]][[[[1, 1]]], [[5, 1]]]Passed
explicit oracle 5[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed
explicit oracle 6[[[[1, 1]]], [[10, 1]]][[[[1, 1]]], [[10, 1]]]Passed
explicit oracle 7[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed

SHA-256 / eb0048f2f9e7ef6d1de1d636d6486dfe95eaa634a3335449f178cdcd326d4e48

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json
import math
import itertools
from fractions import Fraction
N = 1
observations = []
def solve(x):
    a=[list(map(Fraction,row)) for row in x];n=len(a);L=[[Fraction(int(i==j)) for j in range(n)] for i in range(n)];D=[Fraction(0)]*n
    for j in range(n):
     D[j]=a[j][j]-sum(L[j][k]**2*D[k] for k in range(j))
     if not D[j]:return None
     for i in range(j+1,n):
      L[i][j]=(a[i][j]-sum(L[i][k]*L[j][k]*D[k] for k in range(j)))/(D[j])
    return [[[[v.numerator,v.denominator] for v in row] for row in L],[[v.numerator,v.denominator] for v in D]]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[([[14, 2], [2, 2]], [[[[1, 1], [0, 1]], [[1, 7], [1, 1]]], [[14, 1], [12, 7]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]])], [([[11, 3], [3, 14]], [[[[1, 1], [0, 1]], [[3, 11], [1, 1]]], [[11, 1], [145, 11]]]), ([[14, -12], [-12, 14]], [[[[1, 1], [0, 1]], [[-6, 7], [1, 1]]], [[14, 1], [26, 7]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]])], [([[14, -8], [-8, 6]], [[[[1, 1], [0, 1]], [[-4, 7], [1, 1]]], [[14, 1], [10, 7]]]), ([[14, -1], [-1, 6]], [[[[1, 1], [0, 1]], [[-1, 14], [1, 1]]], [[14, 1], [83, 14]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[10]], [[[[1, 1]]], [[10, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[10]], [[[[1, 1]]], [[10, 1]]])], [([[14, -12], [-12, 14]], [[[[1, 1], [0, 1]], [[-6, 7], [1, 1]]], [[14, 1], [26, 7]]]), ([[19, 15], [15, 14]], [[[[1, 1], [0, 1]], [[15, 19], [1, 1]]], [[19, 1], [41, 19]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]]), ([[5]], [[[[1, 1]]], [[5, 1]]])], [([[14, 3], [3, 11]], [[[[1, 1], [0, 1]], [[3, 14], [1, 1]]], [[14, 1], [145, 14]]]), ([[11, 6], [6, 5]], [[[[1, 1], [0, 1]], [[6, 11], [1, 1]]], [[11, 1], [19, 11]]]), ([[2]], [[[[1, 1]]], [[2, 1]]]), ([[20, -8, 15, -3], [-8, 8, -9, -7], [15, -9, 15, 4], [-3, -7, 4, 22]], [[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]), ([[1, 0], [0, 19]], [[[[1, 1], [0, 1]], [[0, 1], [1, 1]]], [[1, 1], [19, 1]]]), ([[3, 2], [2, 5]], [[[[1, 1], [0, 1]], [[2, 3], [1, 1]]], [[3, 1], [11, 3]]]), ([[9, 0], [0, 1]], [[[[1, 1], [0, 1]], [[0, 1], [1, 1]]], [[9, 1], [1, 1]]]), ([[6, 5], [5, 11]], [[[[1, 1], [0, 1]], [[5, 6], [1, 1]]], [[6, 1], [41, 6]]])]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("explicit oracle %d" % i, 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
explicit oracle 0[[[[1, 1], [0, 1]], [[1, 7], [1, 1]]], [[14, 1], [12, 7]]][[[[1, 1], [0, 1]], [[1, 7], [1, 1]]], [[14, 1], [12, 7]]]Passed
explicit oracle 1[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed
explicit oracle 2[[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]][[[[1, 1], [0, 1], [0, 1], [0, 1]], [[-2, 5], [1, 1], [0, 1], [0, 1]], [[3, 4], [-5, 8], [1, 1], [0, 1]], [[-3, 20], [-41, 24], [3, 5], [1, 1]]], [[20, 1], [24, 5], [15, 8], [103, 15]]]Passed
explicit oracle 3[[[[1, 1]]], [[5, 1]]][[[[1, 1]]], [[5, 1]]]Passed
explicit oracle 4[[[[1, 1]]], [[5, 1]]][[[[1, 1]]], [[5, 1]]]Passed
explicit oracle 5[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed
explicit oracle 6[[[[1, 1]]], [[10, 1]]][[[[1, 1]]], [[10, 1]]]Passed
explicit oracle 7[[[[1, 1]]], [[2, 1]]][[[[1, 1]]], [[2, 1]]]Passed

SHA-256 / eeb96c6b72209f89adae646f255b40b066149469e35dab7e32a2543fcfeb25d2

Verification & scope

A deterministic bounded teaching model. Inputs are restricted to the explicit contract; this is not a production algebra library. 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 2026-09-29T14:39:26.805221+00:00.

Case digest / 6536d6fea657ad4b5450d28aea61e2c4039ef0a4b4dad5c94c584cf3a32048ae