FA-97701 / Knitting and sewing pattern grading / Open access

Full and small bust adjustment: adjustment direction · case 01

A D cup sewing a B cup draft is told to do a small bust adjustment.

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

ROOT CAUSE

FBA and SBA labels are swapped.

VERIFIED REPAIR

Use FBA when the body cup exceeds the drafted cup.

Unsuccessful approach: Comparing to a fixed B cup ignores the drafted cup.

Case contract

d = full - high bust (cm); negative -> "error: measurements". Cup index = floor(d/2.5) capped at the last of AA, A, B, C, D, DD, E. delta = index - index(drafted_cup). kind "none", "FBA" (delta > 0) or "SBA". Total adjustment 2.5 cm per cup, per side = total/2; if per side > 4 cm append " (redraft)". Return [cup, kind, per_side float].

Why this case matters

Sewists compare their cup size to the pattern draft cup and perform full or small bust adjustments.

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(high_bust, full_bust, drafted_cup):
    CUPS = ['AA', 'A', 'B', 'C', 'D', 'DD', 'E']
    d = Fraction(str(full_bust)) - Fraction(str(high_bust))
    if d < 0:
        return 'error: measurements'
    idx = min(math.floor(d / Fraction(5, 2)), len(CUPS) - 1)
    cup = CUPS[idx]
    delta = idx - CUPS.index(drafted_cup)
    total = Fraction(5, 2) * abs(delta)
    per = total / 2
    kind = 'none' if delta == 0 else 'SBA' if delta > 0 else 'FBA'
    if per > 4:
        kind += ' (redraft)'
    return [cup, kind, float(per)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['regression: adjustment direction', [96, 108.5, 'A'], ['DD', 'FBA (redraft)', 5.0]],
  ['repair check: adjustment direction', [80, 89, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [92.5, 93.5, 'B'], ['AA', 'SBA', 2.5]],
  ['generated control 2', [84, 99, 'A'], ['E', 'FBA (redraft)', 6.25]],
  ['generated control 3', [92.5, 100.0, 'C'], ['C', 'none', 0.0]]],
 [['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['regression: adjustment direction', [96, 116, 'D'], ['E', 'FBA', 2.5]],
  ['repair check: adjustment direction', [92.5, 101.5, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [80, 85, 'B'], ['B', 'none', 0.0]],
  ['generated control 2', [92.5, 107.5, 'D'], ['E', 'FBA', 2.5]],
  ['generated control 3', [96, 95, 'C'], 'error: measurements']],
 [['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['regression: adjustment direction', [88, 92, 'B'], ['A', 'SBA', 1.25]],
  ['repair check: adjustment direction', [96, 103.5, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [92.5, 91.5, 'D'], 'error: measurements'],
  ['generated control 2', [96, 100, 'B'], ['A', 'SBA', 1.25]],
  ['generated control 3', [84, 85, 'C'], ['AA', 'SBA', 3.75]]],
 [['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['regression: adjustment direction', [88, 95.5, 'A'], ['C', 'FBA', 2.5]],
  ['repair check: adjustment direction', [80, 85, 'A'], ['B', 'FBA', 1.25]],
  ['generated control 1', [84, 83, 'A'], 'error: measurements'],
  ['generated control 2', [80, 87.5, 'A'], ['C', 'FBA', 2.5]],
  ['generated control 3', [88, 108, 'C'], ['E', 'FBA', 3.75]]],
 [['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['regression: adjustment direction', [80, 95, 'A'], ['E', 'FBA (redraft)', 6.25]],
  ['repair check: adjustment direction', [88, 93, 'A'], ['B', 'FBA', 1.25]],
  ['generated control 1', [80, 87.5, 'A'], ['C', 'FBA', 2.5]],
  ['generated control 2', [92.5, 112.5, 'D'], ['E', 'FBA', 2.5]],
  ['generated control 3', [80, 90, 'D'], ['D', 'none', 0.0]]]]
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
matches draft	`['B', 'none', 0.0]`	`['B', 'none', 0.0]`	Passed
big FBA	`['E', 'SBA (redraft)', 5.0]`	`['E', 'FBA (redraft)', 5.0]`	Failed
small bust	`['AA', 'FBA', 3.75]`	`['AA', 'SBA', 3.75]`	Failed
regression: adjustment direction	`['DD', 'SBA (redraft)', 5.0]`	`['DD', 'FBA (redraft)', 5.0]`	Failed
repair check: adjustment direction	`['C', 'FBA', 1.25]`	`['C', 'SBA', 1.25]`	Failed
generated control 1	`['AA', 'FBA', 2.5]`	`['AA', 'SBA', 2.5]`	Failed
generated control 2	`['E', 'SBA (redraft)', 6.25]`	`['E', 'FBA (redraft)', 6.25]`	Failed
generated control 3	`['C', 'none', 0.0]`	`['C', 'none', 0.0]`	Passed

SHA-256 / e67846a2cd87ffc2bc1bf89c55691d4e2ebe9d5d2f8a73011224a73d1f36a13a

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(high_bust, full_bust, drafted_cup):
    CUPS = ['AA', 'A', 'B', 'C', 'D', 'DD', 'E']
    d = Fraction(str(full_bust)) - Fraction(str(high_bust))
    if d < 0:
        return 'error: measurements'
    idx = min(math.floor(d / Fraction(5, 2)), len(CUPS) - 1)
    cup = CUPS[idx]
    delta = idx - CUPS.index(drafted_cup)
    total = Fraction(5, 2) * abs(delta)
    per = total / 2
    kind = 'none' if delta == 0 else 'FBA' if idx > 2 else 'SBA'
    if per > 4:
        kind += ' (redraft)'
    return [cup, kind, float(per)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['regression: adjustment direction', [96, 108.5, 'A'], ['DD', 'FBA (redraft)', 5.0]],
  ['repair check: adjustment direction', [80, 89, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [92.5, 93.5, 'B'], ['AA', 'SBA', 2.5]],
  ['generated control 2', [84, 99, 'A'], ['E', 'FBA (redraft)', 6.25]],
  ['generated control 3', [92.5, 100.0, 'C'], ['C', 'none', 0.0]]],
 [['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['regression: adjustment direction', [96, 116, 'D'], ['E', 'FBA', 2.5]],
  ['repair check: adjustment direction', [92.5, 101.5, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [80, 85, 'B'], ['B', 'none', 0.0]],
  ['generated control 2', [92.5, 107.5, 'D'], ['E', 'FBA', 2.5]],
  ['generated control 3', [96, 95, 'C'], 'error: measurements']],
 [['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['regression: adjustment direction', [88, 92, 'B'], ['A', 'SBA', 1.25]],
  ['repair check: adjustment direction', [96, 103.5, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [92.5, 91.5, 'D'], 'error: measurements'],
  ['generated control 2', [96, 100, 'B'], ['A', 'SBA', 1.25]],
  ['generated control 3', [84, 85, 'C'], ['AA', 'SBA', 3.75]]],
 [['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['regression: adjustment direction', [88, 95.5, 'A'], ['C', 'FBA', 2.5]],
  ['repair check: adjustment direction', [80, 85, 'A'], ['B', 'FBA', 1.25]],
  ['generated control 1', [84, 83, 'A'], 'error: measurements'],
  ['generated control 2', [80, 87.5, 'A'], ['C', 'FBA', 2.5]],
  ['generated control 3', [88, 108, 'C'], ['E', 'FBA', 3.75]]],
 [['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['regression: adjustment direction', [80, 95, 'A'], ['E', 'FBA (redraft)', 6.25]],
  ['repair check: adjustment direction', [88, 93, 'A'], ['B', 'FBA', 1.25]],
  ['generated control 1', [80, 87.5, 'A'], ['C', 'FBA', 2.5]],
  ['generated control 2', [92.5, 112.5, 'D'], ['E', 'FBA', 2.5]],
  ['generated control 3', [80, 90, 'D'], ['D', 'none', 0.0]]]]
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
matches draft	`['B', 'none', 0.0]`	`['B', 'none', 0.0]`	Passed
big FBA	`['E', 'FBA (redraft)', 5.0]`	`['E', 'FBA (redraft)', 5.0]`	Passed
small bust	`['AA', 'SBA', 3.75]`	`['AA', 'SBA', 3.75]`	Passed
regression: adjustment direction	`['DD', 'FBA (redraft)', 5.0]`	`['DD', 'FBA (redraft)', 5.0]`	Passed
repair check: adjustment direction	`['C', 'FBA', 1.25]`	`['C', 'SBA', 1.25]`	Failed
generated control 1	`['AA', 'SBA', 2.5]`	`['AA', 'SBA', 2.5]`	Passed
generated control 2	`['E', 'FBA (redraft)', 6.25]`	`['E', 'FBA (redraft)', 6.25]`	Passed
generated control 3	`['C', 'none', 0.0]`	`['C', 'none', 0.0]`	Passed

SHA-256 / 543d8bb18999fe404194b9439fae1b7e6e7559ccc26da63bfb6ff9bf16f694a2

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(high_bust, full_bust, drafted_cup):
    CUPS = ['AA', 'A', 'B', 'C', 'D', 'DD', 'E']
    d = Fraction(str(full_bust)) - Fraction(str(high_bust))
    if d < 0:
        return 'error: measurements'
    idx = min(math.floor(d / Fraction(5, 2)), len(CUPS) - 1)
    cup = CUPS[idx]
    delta = idx - CUPS.index(drafted_cup)
    total = Fraction(5, 2) * abs(delta)
    per = total / 2
    kind = 'none' if delta == 0 else 'FBA' if delta > 0 else 'SBA'
    if per > 4:
        kind += ' (redraft)'
    return [cup, kind, float(per)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['regression: adjustment direction', [96, 108.5, 'A'], ['DD', 'FBA (redraft)', 5.0]],
  ['repair check: adjustment direction', [80, 89, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [92.5, 93.5, 'B'], ['AA', 'SBA', 2.5]],
  ['generated control 2', [84, 99, 'A'], ['E', 'FBA (redraft)', 6.25]],
  ['generated control 3', [92.5, 100.0, 'C'], ['C', 'none', 0.0]]],
 [['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['regression: adjustment direction', [96, 116, 'D'], ['E', 'FBA', 2.5]],
  ['repair check: adjustment direction', [92.5, 101.5, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [80, 85, 'B'], ['B', 'none', 0.0]],
  ['generated control 2', [92.5, 107.5, 'D'], ['E', 'FBA', 2.5]],
  ['generated control 3', [96, 95, 'C'], 'error: measurements']],
 [['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['regression: adjustment direction', [88, 92, 'B'], ['A', 'SBA', 1.25]],
  ['repair check: adjustment direction', [96, 103.5, 'D'], ['C', 'SBA', 1.25]],
  ['generated control 1', [92.5, 91.5, 'D'], 'error: measurements'],
  ['generated control 2', [96, 100, 'B'], ['A', 'SBA', 1.25]],
  ['generated control 3', [84, 85, 'C'], ['AA', 'SBA', 3.75]]],
 [['negative difference', [90, 89, 'B'], 'error: measurements'],
  ['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['regression: adjustment direction', [88, 95.5, 'A'], ['C', 'FBA', 2.5]],
  ['repair check: adjustment direction', [80, 85, 'A'], ['B', 'FBA', 1.25]],
  ['generated control 1', [84, 83, 'A'], 'error: measurements'],
  ['generated control 2', [80, 87.5, 'A'], ['C', 'FBA', 2.5]],
  ['generated control 3', [88, 108, 'C'], ['E', 'FBA', 3.75]]],
 [['matches draft', [88, 93, 'B'], ['B', 'none', 0.0]],
  ['big FBA', [84, 101, 'B'], ['E', 'FBA (redraft)', 5.0]],
  ['small bust', [92.5, 94, 'C'], ['AA', 'SBA', 3.75]],
  ['regression: adjustment direction', [80, 95, 'A'], ['E', 'FBA (redraft)', 6.25]],
  ['repair check: adjustment direction', [88, 93, 'A'], ['B', 'FBA', 1.25]],
  ['generated control 1', [80, 87.5, 'A'], ['C', 'FBA', 2.5]],
  ['generated control 2', [92.5, 112.5, 'D'], ['E', 'FBA', 2.5]],
  ['generated control 3', [80, 90, 'D'], ['D', 'none', 0.0]]]]
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
matches draft	`['B', 'none', 0.0]`	`['B', 'none', 0.0]`	Passed
big FBA	`['E', 'FBA (redraft)', 5.0]`	`['E', 'FBA (redraft)', 5.0]`	Passed
small bust	`['AA', 'SBA', 3.75]`	`['AA', 'SBA', 3.75]`	Passed
regression: adjustment direction	`['DD', 'FBA (redraft)', 5.0]`	`['DD', 'FBA (redraft)', 5.0]`	Passed
repair check: adjustment direction	`['C', 'SBA', 1.25]`	`['C', 'SBA', 1.25]`	Passed
generated control 1	`['AA', 'SBA', 2.5]`	`['AA', 'SBA', 2.5]`	Passed
generated control 2	`['E', 'FBA (redraft)', 6.25]`	`['E', 'FBA (redraft)', 6.25]`	Passed
generated control 3	`['C', 'none', 0.0]`	`['C', 'none', 0.0]`	Passed

SHA-256 / 34af28225dc57254c9763b5d1b76f39a4dcfc69cdf4da5c2de455419558933ee

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 2026-09-29T14:52:34.768055+00:00.

Case digest / 172115f020acaa433a4aa0411a3bf325026a5068d331d721447c337c8e8dd66a