FA-6416 / Discrete calculus / Open access
Finite impulse valid convolution · case 01
Unreversed kernel computes correlation instead of convolution.
ROOT CAUSE
Unreversed kernel computes correlation instead of convolution.
VERIFIED REPAIR
Apply the specified mathematical contract directly, preserving all terms and boundary cases: return [sum(signal[i+j]*kernel[-1-j] for j in range(len(kernel))) for i in range(len(signal)-len(kernel)+1)]
Unsuccessful approach: Adding kernel and sample values replaces multiplication.
Case contract
Integer sample values and compatible sample-array lengths. Rational results are reduced Fraction strings; spacing is positive unless explicitly stated otherwise. kernel is nonempty; return only full-overlap windows, or [] if the signal is shorter. Exact operational definition: [sum(signal[i+j]*kernel[-1-j] for j in range(len(kernel))) for i in range(len(signal)-len(kernel)+1)]
Why this case matters
Small exact fixtures expose this error without platform timing, external services, or probabilistic observations. Discrete calculus results depend on the stated convention.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
import calendar
import statistics
import itertools
from fractions import Fraction
from datetime import date, datetime, timedelta, timezone
from decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR
N = 1
observations = []
def solve(signal, kernel):
return [sum(signal[i+j]*kernel[j] for j in range(len(kernel))) for i in range(len(signal)-len(kernel)+1)]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1: ([1, 2, 3], [1, 2])', solve(*([1, 2, 3], [1, 2])), [4, 7])
check('fixture 2: ([1, 0, 1], [1, -1])', solve(*([1, 0, 1], [1, -1])), [-1, 1])
check('fixture 3: ([2], [3])', solve(*([2], [3])), [6])
check('fixture 4: ([1], [1, 2])', solve(*([1], [1, 2])), [])
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 |
|---|---|---|---|
| fixture 1: ([1, 2, 3], [1, 2]) | [5, 8] | [4, 7] | Failed |
| fixture 2: ([1, 0, 1], [1, -1]) | [1, -1] | [-1, 1] | Failed |
| fixture 3: ([2], [3]) | [6] | [6] | Passed |
| fixture 4: ([1], [1, 2]) | [] | [] | Passed |
SHA-256 / fa49bf66d825d189dd4209efdd0a910e4c98a6551881ec2d878ea7b346bfe923
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
import calendar
import statistics
import itertools
from fractions import Fraction
from datetime import date, datetime, timedelta, timezone
from decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR
N = 1
observations = []
def solve(signal, kernel):
return [sum(signal[i+j]+kernel[-1-j] for j in range(len(kernel))) for i in range(len(signal)-len(kernel)+1)]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1: ([1, 2, 3], [1, 2])', solve(*([1, 2, 3], [1, 2])), [4, 7])
check('fixture 2: ([1, 0, 1], [1, -1])', solve(*([1, 0, 1], [1, -1])), [-1, 1])
check('fixture 3: ([2], [3])', solve(*([2], [3])), [6])
check('fixture 4: ([1], [1, 2])', solve(*([1], [1, 2])), [])
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 |
|---|---|---|---|
| fixture 1: ([1, 2, 3], [1, 2]) | [6, 8] | [4, 7] | Failed |
| fixture 2: ([1, 0, 1], [1, -1]) | [1, 1] | [-1, 1] | Failed |
| fixture 3: ([2], [3]) | [5] | [6] | Failed |
| fixture 4: ([1], [1, 2]) | [] | [] | Passed |
SHA-256 / d9d2d60179690f39d3573bedb8dd1aee79f6b2195e5bfe593b8ce2d3d960ac8b
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import math
import calendar
import statistics
import itertools
from fractions import Fraction
from datetime import date, datetime, timedelta, timezone
from decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR
N = 1
observations = []
def solve(signal, kernel):
return [sum(signal[i+j]*kernel[-1-j] for j in range(len(kernel))) for i in range(len(signal)-len(kernel)+1)]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1: ([1, 2, 3], [1, 2])', solve(*([1, 2, 3], [1, 2])), [4, 7])
check('fixture 2: ([1, 0, 1], [1, -1])', solve(*([1, 0, 1], [1, -1])), [-1, 1])
check('fixture 3: ([2], [3])', solve(*([2], [3])), [6])
check('fixture 4: ([1], [1, 2])', solve(*([1], [1, 2])), [])
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 |
|---|---|---|---|
| fixture 1: ([1, 2, 3], [1, 2]) | [4, 7] | [4, 7] | Passed |
| fixture 2: ([1, 0, 1], [1, -1]) | [-1, 1] | [-1, 1] | Passed |
| fixture 3: ([2], [3]) | [6] | [6] | Passed |
| fixture 4: ([1], [1, 2]) | [] | [] | Passed |
SHA-256 / 55be508465c39bb8c483856765bc2e5aae9dbb7086d9e3c02393cc786b6854cb
Verification & scope
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 2026-09-29T14:38:01.583087+00:00.
Case digest / a2dd50392e8913828100813cd821c12f6360a8c373b1dab6b8a8d17868a5703a