FA-5921 / Solid geometry / Open access

Cylinder volume divided by pi · case 01

Circumference times height computes lateral area rather than volume.

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

ROOT CAUSE

Circumference times height computes lateral area rather than volume.

THE FAILURE

Circumference times height computes lateral area rather than volume.

Unsuccessful approach: The circular cross-section omits one radius factor.

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 volume divided by pi. Exact operational definition: 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)), 12)
check('fixture 2: (1, 4)', solve(*(1, 4)), 4)
check('fixture 3: (0, 8)', solve(*(0, 8)), 0)
check('fixture 4: (3, 0)', solve(*(3, 0)), 0)
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`	`12`	Passed
fixture 2: (1, 4)	`8`	`4`	Failed
fixture 3: (0, 8)	`0`	`0`	Passed
fixture 4: (3, 0)	`0`	`0`	Passed

SHA-256 / e6fee7923f9e5fe74f713cdfb59dd067be3a51d73f79b2031912492db87851db

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 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)), 12)
check('fixture 2: (1, 4)', solve(*(1, 4)), 4)
check('fixture 3: (0, 8)', solve(*(0, 8)), 0)
check('fixture 4: (3, 0)', solve(*(3, 0)), 0)
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)	`6`	`12`	Failed
fixture 2: (1, 4)	`4`	`4`	Passed
fixture 3: (0, 8)	`0`	`0`	Passed
fixture 4: (3, 0)	`0`	`0`	Passed

SHA-256 / 6554f5b122d787ca410fbbbf84663de80d23e2a7ea11a9fa038908b5ed0e2d61

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 4 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

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 2026-09-29T14:37:55.378932+00:00.

Case digest / 24c245cf52602b4d3c3dd283f0e07e29b5b2f5d64bd7c77a236d96aea314d9fd