FA-97511 / Knitting and sewing pattern grading / Open access

Neckband pick-up counter: unknown edge kind · case 01

A curved edge is silently counted one stitch per row.

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

ROOT CAUSE

Unrecognized edge kinds fall through to a default ratio.

VERIFIED REPAIR

Reject unknown edge kinds.

Unsuccessful approach: Treating them as zero silently drops the edge.

Case contract

Edges [kind, count]: vertical picks up 3 per 4 rows, diagonal 9 per 10 rows, each rounded half-up per edge; horizontal picks 1 per stitch; other kinds -> "error: edge". The rib needs a count of multiple*k + plus; adjust the total up to the next such count (unchanged if already valid). Return [raw_total, adjusted].

Why this case matters

Neckbands and button bands pick up stitches at edge ratios and must fit the rib repeat.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(edges, multiple, plus):
    total = 0
    for kind, n in edges:
        if kind == 'vertical':
            total += math.floor(Fraction(3 * n, 4) + Fraction(1, 2))
        elif kind == 'horizontal':
            total += n
        elif kind == 'diagonal':
            total += math.floor(Fraction(9 * n, 10) + Fraction(1, 2))
        else:
            total += n
    r = (total - plus) % multiple
    adjusted = total if r == 0 else total + (multiple - r)
    return [total, adjusted]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['regression: unknown edge kind',
   [[['vertical', 10], ['vertical', 41], ['horizontal', 41], ['vertical', 20], ['curve', 10]], 6, 1],
   'error: edge'],
  ['repair check: unknown edge kind',
   [[['diagonal', 10], ['diagonal', 7], ['vertical', 22], ['curve', 10]], 1, 1], 'error: edge'],
  ['generated control 1', [[['vertical', 10], ['diagonal', 18]], 2, 2], [24, 24]],
  ['generated control 2', [[['horizontal', 13], ['horizontal', 13], ['vertical', 10]], 6, 0], [34, 36]],
  ['generated control 3', [[['vertical', 41], ['vertical', 7], ['horizontal', 10], ['diagonal', 41]], 4, 0],
   [83, 84]]],
 [['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['regression: unknown edge kind',
   [[['vertical', 18], ['vertical', 18], ['vertical', 7], ['curve', 10]], 2, 3], 'error: edge'],
  ['repair check: unknown edge kind', [[['horizontal', 60], ['curve', 10]], 1, 0], 'error: edge'],
  ['generated control 1', [[['horizontal', 18], ['diagonal', 30], ['diagonal', 10]], 4, 2], [54, 54]],
  ['generated control 2', [[['horizontal', 22], ['vertical', 10], ['diagonal', 20]], 4, 0], [48, 48]],
  ['generated control 3', [[['diagonal', 18], ['vertical', 18], ['diagonal', 7]], 1, 1], [36, 36]]],
 [['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['regression: unknown edge kind',
   [[['horizontal', 30], ['vertical', 10], ['vertical', 20], ['curve', 10]], 6, 3], 'error: edge'],
  ['repair check: unknown edge kind',
   [[['horizontal', 60], ['vertical', 7], ['diagonal', 7], ['curve', 10]], 1, 0], 'error: edge'],
  ['generated control 1',
   [[['horizontal', 60], ['horizontal', 41], ['vertical', 60], ['horizontal', 30]], 1, 0], [176, 176]],
  ['generated control 2', [[['horizontal', 22], ['horizontal', 10]], 4, 3], [32, 35]],
  ['generated control 3', [[['vertical', 13], ['horizontal', 10]], 2, 3], [20, 21]]],
 [['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['regression: unknown edge kind',
   [[['vertical', 20], ['vertical', 30], ['vertical', 18], ['curve', 10]], 4, 1], 'error: edge'],
  ['repair check: unknown edge kind', [[['diagonal', 20], ['diagonal', 41], ['curve', 10]], 4, 1],
   'error: edge'],
  ['generated control 1', [[['horizontal', 22], ['vertical', 41]], 1, 2], [53, 53]],
  ['generated control 2', [[['vertical', 7], ['vertical', 20], ['diagonal', 10]], 4, 0], [29, 32]],
  ['generated control 3', [[['vertical', 20], ['vertical', 30], ['vertical', 60], ['horizontal', 7]], 6, 1],
   [90, 91]]],
 [['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['regression: unknown edge kind',
   [[['horizontal', 22], ['vertical', 7], ['vertical', 60], ['curve', 10]], 4, 3], 'error: edge'],
  ['repair check: unknown edge kind',
   [[['diagonal', 10], ['diagonal', 7], ['vertical', 22], ['vertical', 22], ['curve', 10]], 1, 3],
   'error: edge'],
  ['generated control 1', [[['horizontal', 18], ['vertical', 41], ['diagonal', 30]], 1, 3], [76, 76]],
  ['generated control 2', [[['vertical', 22]], 2, 1], [17, 17]],
  ['generated control 3', [[['vertical', 13], ['vertical', 60], ['horizontal', 18], ['diagonal', 10]], 4, 1],
   [82, 85]]]]
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
front neck	`[82, 82]`	`[82, 82]`	Passed
already valid	`[22, 22]`	`[22, 22]`	Passed
diagonal edge	`[12, 12]`	`[12, 12]`	Passed
regression: unknown edge kind	`[105, 109]`	`error: edge`	Failed
repair check: unknown edge kind	`[42, 42]`	`error: edge`	Failed
generated control 1	`[24, 24]`	`[24, 24]`	Passed
generated control 2	`[34, 36]`	`[34, 36]`	Passed
generated control 3	`[83, 84]`	`[83, 84]`	Passed

SHA-256 / 27b79637822f05cda8f444408f4ff69b8cb328481b426b3b83670da7d8415b64

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(edges, multiple, plus):
    total = 0
    for kind, n in edges:
        if kind == 'vertical':
            total += math.floor(Fraction(3 * n, 4) + Fraction(1, 2))
        elif kind == 'horizontal':
            total += n
        elif kind == 'diagonal':
            total += math.floor(Fraction(9 * n, 10) + Fraction(1, 2))
        else:
            total += 0
    r = (total - plus) % multiple
    adjusted = total if r == 0 else total + (multiple - r)
    return [total, adjusted]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['regression: unknown edge kind',
   [[['vertical', 10], ['vertical', 41], ['horizontal', 41], ['vertical', 20], ['curve', 10]], 6, 1],
   'error: edge'],
  ['repair check: unknown edge kind',
   [[['diagonal', 10], ['diagonal', 7], ['vertical', 22], ['curve', 10]], 1, 1], 'error: edge'],
  ['generated control 1', [[['vertical', 10], ['diagonal', 18]], 2, 2], [24, 24]],
  ['generated control 2', [[['horizontal', 13], ['horizontal', 13], ['vertical', 10]], 6, 0], [34, 36]],
  ['generated control 3', [[['vertical', 41], ['vertical', 7], ['horizontal', 10], ['diagonal', 41]], 4, 0],
   [83, 84]]],
 [['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['regression: unknown edge kind',
   [[['vertical', 18], ['vertical', 18], ['vertical', 7], ['curve', 10]], 2, 3], 'error: edge'],
  ['repair check: unknown edge kind', [[['horizontal', 60], ['curve', 10]], 1, 0], 'error: edge'],
  ['generated control 1', [[['horizontal', 18], ['diagonal', 30], ['diagonal', 10]], 4, 2], [54, 54]],
  ['generated control 2', [[['horizontal', 22], ['vertical', 10], ['diagonal', 20]], 4, 0], [48, 48]],
  ['generated control 3', [[['diagonal', 18], ['vertical', 18], ['diagonal', 7]], 1, 1], [36, 36]]],
 [['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['regression: unknown edge kind',
   [[['horizontal', 30], ['vertical', 10], ['vertical', 20], ['curve', 10]], 6, 3], 'error: edge'],
  ['repair check: unknown edge kind',
   [[['horizontal', 60], ['vertical', 7], ['diagonal', 7], ['curve', 10]], 1, 0], 'error: edge'],
  ['generated control 1',
   [[['horizontal', 60], ['horizontal', 41], ['vertical', 60], ['horizontal', 30]], 1, 0], [176, 176]],
  ['generated control 2', [[['horizontal', 22], ['horizontal', 10]], 4, 3], [32, 35]],
  ['generated control 3', [[['vertical', 13], ['horizontal', 10]], 2, 3], [20, 21]]],
 [['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['regression: unknown edge kind',
   [[['vertical', 20], ['vertical', 30], ['vertical', 18], ['curve', 10]], 4, 1], 'error: edge'],
  ['repair check: unknown edge kind', [[['diagonal', 20], ['diagonal', 41], ['curve', 10]], 4, 1],
   'error: edge'],
  ['generated control 1', [[['horizontal', 22], ['vertical', 41]], 1, 2], [53, 53]],
  ['generated control 2', [[['vertical', 7], ['vertical', 20], ['diagonal', 10]], 4, 0], [29, 32]],
  ['generated control 3', [[['vertical', 20], ['vertical', 30], ['vertical', 60], ['horizontal', 7]], 6, 1],
   [90, 91]]],
 [['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['regression: unknown edge kind',
   [[['horizontal', 22], ['vertical', 7], ['vertical', 60], ['curve', 10]], 4, 3], 'error: edge'],
  ['repair check: unknown edge kind',
   [[['diagonal', 10], ['diagonal', 7], ['vertical', 22], ['vertical', 22], ['curve', 10]], 1, 3],
   'error: edge'],
  ['generated control 1', [[['horizontal', 18], ['vertical', 41], ['diagonal', 30]], 1, 3], [76, 76]],
  ['generated control 2', [[['vertical', 22]], 2, 1], [17, 17]],
  ['generated control 3', [[['vertical', 13], ['vertical', 60], ['horizontal', 18], ['diagonal', 10]], 4, 1],
   [82, 85]]]]
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
front neck	`[82, 82]`	`[82, 82]`	Passed
already valid	`[22, 22]`	`[22, 22]`	Passed
diagonal edge	`[12, 12]`	`[12, 12]`	Passed
regression: unknown edge kind	`[95, 97]`	`error: edge`	Failed
repair check: unknown edge kind	`[32, 32]`	`error: edge`	Failed
generated control 1	`[24, 24]`	`[24, 24]`	Passed
generated control 2	`[34, 36]`	`[34, 36]`	Passed
generated control 3	`[83, 84]`	`[83, 84]`	Passed

SHA-256 / 86e2cbd7b64a4354d1162c304c4bf9af4c703265e4e5f8e61aa20789241bbc8c

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(edges, multiple, plus):
    total = 0
    for kind, n in edges:
        if kind == 'vertical':
            total += math.floor(Fraction(3 * n, 4) + Fraction(1, 2))
        elif kind == 'horizontal':
            total += n
        elif kind == 'diagonal':
            total += math.floor(Fraction(9 * n, 10) + Fraction(1, 2))
        else:
            return 'error: edge'
    r = (total - plus) % multiple
    adjusted = total if r == 0 else total + (multiple - r)
    return [total, adjusted]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['regression: unknown edge kind',
   [[['vertical', 10], ['vertical', 41], ['horizontal', 41], ['vertical', 20], ['curve', 10]], 6, 1],
   'error: edge'],
  ['repair check: unknown edge kind',
   [[['diagonal', 10], ['diagonal', 7], ['vertical', 22], ['curve', 10]], 1, 1], 'error: edge'],
  ['generated control 1', [[['vertical', 10], ['diagonal', 18]], 2, 2], [24, 24]],
  ['generated control 2', [[['horizontal', 13], ['horizontal', 13], ['vertical', 10]], 6, 0], [34, 36]],
  ['generated control 3', [[['vertical', 41], ['vertical', 7], ['horizontal', 10], ['diagonal', 41]], 4, 0],
   [83, 84]]],
 [['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['regression: unknown edge kind',
   [[['vertical', 18], ['vertical', 18], ['vertical', 7], ['curve', 10]], 2, 3], 'error: edge'],
  ['repair check: unknown edge kind', [[['horizontal', 60], ['curve', 10]], 1, 0], 'error: edge'],
  ['generated control 1', [[['horizontal', 18], ['diagonal', 30], ['diagonal', 10]], 4, 2], [54, 54]],
  ['generated control 2', [[['horizontal', 22], ['vertical', 10], ['diagonal', 20]], 4, 0], [48, 48]],
  ['generated control 3', [[['diagonal', 18], ['vertical', 18], ['diagonal', 7]], 1, 1], [36, 36]]],
 [['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['regression: unknown edge kind',
   [[['horizontal', 30], ['vertical', 10], ['vertical', 20], ['curve', 10]], 6, 3], 'error: edge'],
  ['repair check: unknown edge kind',
   [[['horizontal', 60], ['vertical', 7], ['diagonal', 7], ['curve', 10]], 1, 0], 'error: edge'],
  ['generated control 1',
   [[['horizontal', 60], ['horizontal', 41], ['vertical', 60], ['horizontal', 30]], 1, 0], [176, 176]],
  ['generated control 2', [[['horizontal', 22], ['horizontal', 10]], 4, 3], [32, 35]],
  ['generated control 3', [[['vertical', 13], ['horizontal', 10]], 2, 3], [20, 21]]],
 [['unknown edge', [[['curve', 10]], 2, 0], 'error: edge'],
  ['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['regression: unknown edge kind',
   [[['vertical', 20], ['vertical', 30], ['vertical', 18], ['curve', 10]], 4, 1], 'error: edge'],
  ['repair check: unknown edge kind', [[['diagonal', 20], ['diagonal', 41], ['curve', 10]], 4, 1],
   'error: edge'],
  ['generated control 1', [[['horizontal', 22], ['vertical', 41]], 1, 2], [53, 53]],
  ['generated control 2', [[['vertical', 7], ['vertical', 20], ['diagonal', 10]], 4, 0], [29, 32]],
  ['generated control 3', [[['vertical', 20], ['vertical', 30], ['vertical', 60], ['horizontal', 7]], 6, 1],
   [90, 91]]],
 [['front neck', [[['vertical', 40], ['horizontal', 22], ['vertical', 40]], 4, 2], [82, 82]],
  ['already valid', [[['horizontal', 22]], 4, 2], [22, 22]],
  ['diagonal edge', [[['diagonal', 13]], 2, 0], [12, 12]],
  ['regression: unknown edge kind',
   [[['horizontal', 22], ['vertical', 7], ['vertical', 60], ['curve', 10]], 4, 3], 'error: edge'],
  ['repair check: unknown edge kind',
   [[['diagonal', 10], ['diagonal', 7], ['vertical', 22], ['vertical', 22], ['curve', 10]], 1, 3],
   'error: edge'],
  ['generated control 1', [[['horizontal', 18], ['vertical', 41], ['diagonal', 30]], 1, 3], [76, 76]],
  ['generated control 2', [[['vertical', 22]], 2, 1], [17, 17]],
  ['generated control 3', [[['vertical', 13], ['vertical', 60], ['horizontal', 18], ['diagonal', 10]], 4, 1],
   [82, 85]]]]
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
front neck	`[82, 82]`	`[82, 82]`	Passed
already valid	`[22, 22]`	`[22, 22]`	Passed
diagonal edge	`[12, 12]`	`[12, 12]`	Passed
regression: unknown edge kind	`error: edge`	`error: edge`	Passed
repair check: unknown edge kind	`error: edge`	`error: edge`	Passed
generated control 1	`[24, 24]`	`[24, 24]`	Passed
generated control 2	`[34, 36]`	`[34, 36]`	Passed
generated control 3	`[83, 84]`	`[83, 84]`	Passed

SHA-256 / 4a0567f69f6c992bb723b43d1f9587d1f40bc8adda573e047abb28a9520abaad

Verification & scope

A deterministic toy contract stated in full here; it is a bounded teaching model, not an authoritative reference or standards implementation. 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 2026-09-29T14:52:32.955192+00:00.

Case digest / a696f2f343fdae14768cb2c50bcd3fc6fa7829f6e1239e3062aad2d5e1b0e9e4