FA-5961 / Solid geometry / Open access

Cylinder total surface divided by pi · case 01

The two end disks are omitted.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The two end disks are omitted.

VERIFIED REPAIR

Apply the specified mathematical contract directly, preserving all terms and boundary cases: return 2*r*(r+h)

Unsuccessful approach: The curved surface loses one factor of two.

Case contract

Nonnegative integer dimensions; exact products and ordinary Python real division. Quantities named divided by pi or pi-squared deliberately omit that factor from the returned result. Cylinder total surface divided by pi. Exact operational definition: 2*r*(r+h)

Why this case matters

Small exact fixtures expose this error without platform timing, external services, or probabilistic observations. Solid geometry 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(r, h):
    return 2*r*h
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1: (2, 3)', solve(*(2, 3)), 20)
check('fixture 2: (1, 0)', solve(*(1, 0)), 2)
check('fixture 3: (0, 5)', solve(*(0, 5)), 0)
check('fixture 4: (3, 4)', solve(*(3, 4)), 42)
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: (2, 3)	`12`	`20`	Failed
fixture 2: (1, 0)	`0`	`2`	Failed
fixture 3: (0, 5)	`0`	`0`	Passed
fixture 4: (3, 4)	`24`	`42`	Failed

SHA-256 / a0ac239a716ddd821e6b00077213efeef12089b4f03399eff4998c57bf5073f1

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(r, h):
    return 2*r*r+r*h
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1: (2, 3)', solve(*(2, 3)), 20)
check('fixture 2: (1, 0)', solve(*(1, 0)), 2)
check('fixture 3: (0, 5)', solve(*(0, 5)), 0)
check('fixture 4: (3, 4)', solve(*(3, 4)), 42)
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: (2, 3)	`14`	`20`	Failed
fixture 2: (1, 0)	`2`	`2`	Passed
fixture 3: (0, 5)	`0`	`0`	Passed
fixture 4: (3, 4)	`30`	`42`	Failed

SHA-256 / 90eafa63168f95965b8b7784bbd8b039542cb999c1fd8b0c13a44370675f2c11

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(r, h):
    return 2*r*(r+h)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1: (2, 3)', solve(*(2, 3)), 20)
check('fixture 2: (1, 0)', solve(*(1, 0)), 2)
check('fixture 3: (0, 5)', solve(*(0, 5)), 0)
check('fixture 4: (3, 4)', solve(*(3, 4)), 42)
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: (2, 3)	`20`	`20`	Passed
fixture 2: (1, 0)	`2`	`2`	Passed
fixture 3: (0, 5)	`0`	`0`	Passed
fixture 4: (3, 4)	`42`	`42`	Passed

SHA-256 / 7d2cbb07e6a0beacfc59d2a7a68e94680ac8698c235a8b99b5671620600f60b9

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 2026-09-29T14:37:56.016144+00:00.

Case digest / 814dcbd74252a99d819ff47e9f09275fd998ee3cf3d678149ceeb775dbae0674