FA-58136 / Double-entry ledger accounting / Open access

Aging-based allowance adjustment: per-bucket rounding · case 01

Required allowance is a few cents short.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Bucket reserves are truncated instead of rounded half-up.

VERIFIED REPAIR

Round each bucket reserve half-up.

Unsuccessful approach: Rounding any fraction up over-reserves buckets below the half-cent mark.

Case contract

x = {'as_of': day, 'invoices': [[id, due_day, open cents]], 'rates': [[max_days_past_due or None, basis points]] ascending, 'allowance': existing credit balance (negative = debit balance), 'writeoffs': ids}. Written-off invoices leave receivables and reduce the allowance by their amount. Days past due = max(0, as_of - due); an invoice goes in the first bucket whose limit is None or >= days. Required allowance = sum over buckets of bucket total * bp / 10000 rounded half-up per bucket. Return {'buckets', 'required', 'adjustment': required - allowance after write-offs, 'net_ar'}.

Why this case matters

Ledger software must keep debits equal to credits and apply normal-balance, period and cutoff rules exactly; small sign or boundary slips silently misstate financial statements.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    wo = set(x['writeoffs'])
    allowance = x['allowance']
    buckets = [0] * len(x['rates'])
    for iid, due, amt in x['invoices']:
        if iid in wo:
            allowance -= amt
            continue
        past = max(0, x['as_of'] - due)
        for k, (limit, bp) in enumerate(x['rates']):
            if limit is None or past <= limit:
                buckets[k] += amt
                break
    required = 0
    for total, (limit, bp) in zip(buckets, x['rates']):
        q, r = divmod(total * bp, 10000)
        required += q
    ar = sum(buckets)
    return {'buckets': buckets, 'required': required, 'adjustment': required - allowance, 'net_ar': ar - required}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', -100, 5], ['I1', 39, 333], ['I2', 9, 2500], ['I3', -100, 4000], ['I4', 69, 150], ['I5', 70, 2500], ['I6', 55, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5', 'I6']}, {'buckets': [0, 0, 150, 333, 6505], 'required': 5035, 'adjustment': 11535, 'net_ar': 1953}], ['control 1', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 110, 150], ['I2', 100, 4000], ['I3', 40, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [4150, 0, 8000], 'required': 4083, 'adjustment': 4083, 'net_ar': 8067}], ['control 2', {'as_of': 100, 'invoices': [['I0', 70, 1000], ['I1', 99, 5], ['I2', 99, 5], ['I3', 110, 5], ['I4', -100, 333], ['I5', -100, 1000], ['I6', 54, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0', 'I1', 'I4']}, {'buckets': [5, 5, 4000, 0, 1000], 'required': 1350, 'adjustment': 2838, 'net_ar': 3660}], ['control 3', {'as_of': 100, 'invoices': [['I0', 10, 1000], ['I1', 110, 2500], ['I2', 69, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 4000, 1000, 0], 'required': 1000, 'adjustment': 3300, 'net_ar': 4000}], ['control 4', {'as_of': 100, 'invoices': [['I0', 40, 2500], ['I1', 99, 4000], ['I2', 9, 1000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 4000, 3500], 'required': 2250, 'adjustment': 2250, 'net_ar': 5250}], ['control 5', {'as_of': 100, 'invoices': [['I0', 55, 2500], ['I1', 71, 1000], ['I2', 10, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [0, 0, 2500, 4000, 0], 'required': 1975, 'adjustment': 2975, 'net_ar': 4525}], ['control 6', {'as_of': 100, 'invoices': [['I0', 55, 4000], ['I1', 54, 333], ['I2', 40, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [0, 0, 6500, 0, 0], 'required': 975, 'adjustment': 1308, 'net_ar': 5525}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 99, 2500], ['I1', 69, 1000], ['I2', 55, 333], ['I3', 39, 1000], ['I4', 39, 333], ['I5', 40, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1', 'I4', 'I5']}, {'buckets': [0, 2500, 333, 1000, 0], 'required': 575, 'adjustment': 5708, 'net_ar': 3258}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', 54, 2500], ['I1', 55, 5], ['I2', 10, 1000], ['I3', 71, 333], ['I4', 71, 1000], ['I5', 100, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': ['I2', 'I5']}, {'buckets': [0, 1338, 2500], 'required': 1417, 'adjustment': 2572, 'net_ar': 2421}], ['control 1', {'as_of': 100, 'invoices': [['I0', -100, 150], ['I1', 40, 1000], ['I2', 40, 5], ['I3', 39, 1000], ['I4', 9, 150], ['I5', 10, 1000], ['I6', 10, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': ['I2', 'I5']}, {'buckets': [0, 0, 2450], 'required': 1225, 'adjustment': 2030, 'net_ar': 1225}], ['control 2', {'as_of': 100, 'invoices': [['I0', 54, 1000], ['I1', 69, 333], ['I2', 55, 150], ['I3', 70, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 633, 1000], 'required': 579, 'adjustment': 379, 'net_ar': 1054}], ['control 3', {'as_of': 100, 'invoices': [['I0', 55, 333], ['I1', 10, 150], ['I2', 99, 1000], ['I3', 54, 5], ['I4', 69, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0']}, {'buckets': [0, 1000, 155, 150, 0], 'required': 133, 'adjustment': 266, 'net_ar': 1172}], ['control 4', {'as_of': 100, 'invoices': [['I0', 9, 1000], ['I1', 55, 2500], ['I2', 110, 2500], ['I3', 70, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [2500, 2500, 2500, 0, 1000], 'required': 1275, 'adjustment': 1425, 'net_ar': 7225}], ['control 5', {'as_of': 100, 'invoices': [['I0', 10, 333], ['I1', 110, 5], ['I2', -100, 1000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1', 'I2']}, {'buckets': [0, 0, 0, 333, 0], 'required': 133, 'adjustment': 938, 'net_ar': 200}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 54, 150], ['I1', 71, 4000], ['I2', 70, 2500], ['I3', 110, 150], ['I4', 99, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I3']}, {'buckets': [0, 6505, 150, 0, 0], 'required': 348, 'adjustment': -2, 'net_ar': 6307}], ['control 1', {'as_of': 100, 'invoices': [['I0', 69, 4000], ['I1', 110, 4000], ['I2', 55, 1000], ['I3', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [4000, 0, 5000, 0, 0], 'required': 790, 'adjustment': 4790, 'net_ar': 8210}], ['control 2', {'as_of': 100, 'invoices': [['I0', 100, 4000], ['I1', 69, 1000], ['I2', 55, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [4000, 5000, 0], 'required': 705, 'adjustment': 505, 'net_ar': 8295}], ['control 3', {'as_of': 100, 'invoices': [['I0', 70, 4000], ['I1', 54, 1000], ['I2', 70, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 4005, 1000, 0, 0], 'required': 350, 'adjustment': 150, 'net_ar': 4655}], ['control 4', {'as_of': 100, 'invoices': [['I0', 110, 5], ['I1', 10, 5], ['I2', 100, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0', 'I2']}, {'buckets': [0, 0, 0, 5, 0], 'required': 2, 'adjustment': 2657, 'net_ar': 3}], ['control 5', {'as_of': 100, 'invoices': [['I0', 10, 1000], ['I1', 10, 150], ['I2', 39, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 0, 5000, 0], 'required': 2000, 'adjustment': 1950, 'net_ar': 3000}], ['control 6', {'as_of': 100, 'invoices': [['I0', 70, 5], ['I1', 100, 4000], ['I2', 99, 5], ['I3', 54, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I3']}, {'buckets': [4000, 5, 0, 0, 0], 'required': 40, 'adjustment': 50, 'net_ar': 3965}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 110, 150], ['I1', 10, 1000], ['I2', 70, 150], ['I3', 99, 1000], ['I4', 100, 2500], ['I5', 55, 333], ['I6', 54, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5', 'I6']}, {'buckets': [2650, 1150, 0, 1000, 0], 'required': 485, 'adjustment': 968, 'net_ar': 4315}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', 54, 1000], ['I1', 100, 5], ['I2', 70, 150], ['I3', 110, 150], ['I4', 100, 2500], ['I5', -100, 333], ['I6', 100, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': []}, {'buckets': [2805, 150, 1000, 0, 333], 'required': 436, 'adjustment': 436, 'net_ar': 3852}], ['control 1', {'as_of': 100, 'invoices': [['I0', 110, 2500], ['I1', 69, 150], ['I2', 54, 2500], ['I3', 10, 333]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [2500, 0, 2500, 333, 0], 'required': 533, 'adjustment': 483, 'net_ar': 4800}], ['control 2', {'as_of': 100, 'invoices': [['I0', 69, 2500], ['I1', 69, 150], ['I2', 55, 5], ['I3', 71, 1000], ['I4', 55, 4000], ['I5', -100, 2500], ['I6', 69, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': []}, {'buckets': [0, 1000, 10655, 0, 2500], 'required': 3523, 'adjustment': 3023, 'net_ar': 10632}], ['control 3', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 9, 1000], ['I2', -100, 2500], ['I3', -100, 150], ['I4', 70, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I0']}, {'buckets': [0, 4000, 3650], 'required': 2325, 'adjustment': 6325, 'net_ar': 5325}], ['control 4', {'as_of': 100, 'invoices': [['I0', -100, 2500], ['I1', 54, 4000], ['I2', 55, 4000], ['I3', 9, 1000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 4000, 7500], 'required': 4250, 'adjustment': 4400, 'net_ar': 7250}], ['control 5', {'as_of': 100, 'invoices': [['I0', 39, 333], ['I1', 39, 1000], ['I2', 100, 150], ['I3', 54, 4000], ['I4', -100, 5], ['I5', 71, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I5']}, {'buckets': [150, 0, 5338], 'required': 2672, 'adjustment': 2822, 'net_ar': 2816}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 70, 4000], ['I1', 70, 2500], ['I2', 100, 4000], ['I3', 71, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [4000, 4005, 0], 'required': 581, 'adjustment': 3081, 'net_ar': 7424}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', -100, 4000], ['I1', 9, 4000], ['I2', 110, 1000], ['I3', 100, 333], ['I4', 9, 5], ['I5', 99, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I5']}, {'buckets': [1333, 0, 0, 0, 8005], 'required': 6017, 'adjustment': 6317, 'net_ar': 3321}], ['control 1', {'as_of': 100, 'invoices': [['I0', 39, 5], ['I1', 99, 4000], ['I2', 55, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I1']}, {'buckets': [0, 0, 4000, 0, 0], 'required': 600, 'adjustment': 4605, 'net_ar': 3400}], ['control 2', {'as_of': 100, 'invoices': [['I0', 54, 5], ['I1', 40, 5], ['I2', 99, 333], ['I3', 71, 150], ['I4', 54, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 483, 4010], 'required': 2065, 'adjustment': 2065, 'net_ar': 2428}], ['control 3', {'as_of': 100, 'invoices': [['I0', -100, 2500], ['I1', 39, 4000], ['I2', 55, 1000], ['I3', 40, 4000], ['I4', 40, 4000], ['I5', 54, 2500], ['I6', 99, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5']}, {'buckets': [0, 4000, 9000, 4000, 2500], 'required': 5025, 'adjustment': 7525, 'net_ar': 14475}], ['control 4', {'as_of': 100, 'invoices': [['I0', 55, 5], ['I1', 100, 150], ['I2', 99, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I1', 'I2']}, {'buckets': [0, 0, 0, 0, 0], 'required': 0, 'adjustment': 305, 'net_ar': 0}], ['control 5', {'as_of': 100, 'invoices': [['I0', 39, 2500], ['I1', 39, 150], ['I2', 10, 4000], ['I3', 9, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 0, 0, 6650, 2500], 'required': 4535, 'adjustment': 4335, 'net_ar': 4615}]]]
for label, args, expected in fixtures[N-1]:
    try:
        actual = solve(args)
    except Exception as exc:
        actual = 'raised ' + type(exc).__name__
    check(label, actual, 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
regression: per-bucket rounding	`{'adjustment': 11533, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 1955, 'required': 5033}`	`{'adjustment': 11535, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 1953, 'required': 5035}`	Failed
control 1	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	Passed
control 2	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 3660, 'required': 1350}`	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 3660, 'required': 1350}`	Passed
control 3	`{'adjustment': 3300, 'buckets': [0, 0, 4000, 1000, 0], 'net_ar': 4000, 'required': 1000}`	`{'adjustment': 3300, 'buckets': [0, 0, 4000, 1000, 0], 'net_ar': 4000, 'required': 1000}`	Passed
control 4	`{'adjustment': 2250, 'buckets': [0, 4000, 3500], 'net_ar': 5250, 'required': 2250}`	`{'adjustment': 2250, 'buckets': [0, 4000, 3500], 'net_ar': 5250, 'required': 2250}`	Passed
control 5	`{'adjustment': 2975, 'buckets': [0, 0, 2500, 4000, 0], 'net_ar': 4525, 'required': 1975}`	`{'adjustment': 2975, 'buckets': [0, 0, 2500, 4000, 0], 'net_ar': 4525, 'required': 1975}`	Passed
control 6	`{'adjustment': 1308, 'buckets': [0, 0, 6500, 0, 0], 'net_ar': 5525, 'required': 975}`	`{'adjustment': 1308, 'buckets': [0, 0, 6500, 0, 0], 'net_ar': 5525, 'required': 975}`	Passed

SHA-256 / 9ff7b80e79d73f89d460d8c22462e986c4d328a39ee5ea1b1353eed101985ee7

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    wo = set(x['writeoffs'])
    allowance = x['allowance']
    buckets = [0] * len(x['rates'])
    for iid, due, amt in x['invoices']:
        if iid in wo:
            allowance -= amt
            continue
        past = max(0, x['as_of'] - due)
        for k, (limit, bp) in enumerate(x['rates']):
            if limit is None or past <= limit:
                buckets[k] += amt
                break
    required = 0
    for total, (limit, bp) in zip(buckets, x['rates']):
        q, r = divmod(total * bp, 10000)
        required += q + (1 if r else 0)
    ar = sum(buckets)
    return {'buckets': buckets, 'required': required, 'adjustment': required - allowance, 'net_ar': ar - required}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', -100, 5], ['I1', 39, 333], ['I2', 9, 2500], ['I3', -100, 4000], ['I4', 69, 150], ['I5', 70, 2500], ['I6', 55, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5', 'I6']}, {'buckets': [0, 0, 150, 333, 6505], 'required': 5035, 'adjustment': 11535, 'net_ar': 1953}], ['control 1', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 110, 150], ['I2', 100, 4000], ['I3', 40, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [4150, 0, 8000], 'required': 4083, 'adjustment': 4083, 'net_ar': 8067}], ['control 2', {'as_of': 100, 'invoices': [['I0', 70, 1000], ['I1', 99, 5], ['I2', 99, 5], ['I3', 110, 5], ['I4', -100, 333], ['I5', -100, 1000], ['I6', 54, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0', 'I1', 'I4']}, {'buckets': [5, 5, 4000, 0, 1000], 'required': 1350, 'adjustment': 2838, 'net_ar': 3660}], ['control 3', {'as_of': 100, 'invoices': [['I0', 10, 1000], ['I1', 110, 2500], ['I2', 69, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 4000, 1000, 0], 'required': 1000, 'adjustment': 3300, 'net_ar': 4000}], ['control 4', {'as_of': 100, 'invoices': [['I0', 40, 2500], ['I1', 99, 4000], ['I2', 9, 1000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 4000, 3500], 'required': 2250, 'adjustment': 2250, 'net_ar': 5250}], ['control 5', {'as_of': 100, 'invoices': [['I0', 55, 2500], ['I1', 71, 1000], ['I2', 10, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [0, 0, 2500, 4000, 0], 'required': 1975, 'adjustment': 2975, 'net_ar': 4525}], ['control 6', {'as_of': 100, 'invoices': [['I0', 55, 4000], ['I1', 54, 333], ['I2', 40, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [0, 0, 6500, 0, 0], 'required': 975, 'adjustment': 1308, 'net_ar': 5525}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 99, 2500], ['I1', 69, 1000], ['I2', 55, 333], ['I3', 39, 1000], ['I4', 39, 333], ['I5', 40, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1', 'I4', 'I5']}, {'buckets': [0, 2500, 333, 1000, 0], 'required': 575, 'adjustment': 5708, 'net_ar': 3258}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', 54, 2500], ['I1', 55, 5], ['I2', 10, 1000], ['I3', 71, 333], ['I4', 71, 1000], ['I5', 100, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': ['I2', 'I5']}, {'buckets': [0, 1338, 2500], 'required': 1417, 'adjustment': 2572, 'net_ar': 2421}], ['control 1', {'as_of': 100, 'invoices': [['I0', -100, 150], ['I1', 40, 1000], ['I2', 40, 5], ['I3', 39, 1000], ['I4', 9, 150], ['I5', 10, 1000], ['I6', 10, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': ['I2', 'I5']}, {'buckets': [0, 0, 2450], 'required': 1225, 'adjustment': 2030, 'net_ar': 1225}], ['control 2', {'as_of': 100, 'invoices': [['I0', 54, 1000], ['I1', 69, 333], ['I2', 55, 150], ['I3', 70, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 633, 1000], 'required': 579, 'adjustment': 379, 'net_ar': 1054}], ['control 3', {'as_of': 100, 'invoices': [['I0', 55, 333], ['I1', 10, 150], ['I2', 99, 1000], ['I3', 54, 5], ['I4', 69, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0']}, {'buckets': [0, 1000, 155, 150, 0], 'required': 133, 'adjustment': 266, 'net_ar': 1172}], ['control 4', {'as_of': 100, 'invoices': [['I0', 9, 1000], ['I1', 55, 2500], ['I2', 110, 2500], ['I3', 70, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [2500, 2500, 2500, 0, 1000], 'required': 1275, 'adjustment': 1425, 'net_ar': 7225}], ['control 5', {'as_of': 100, 'invoices': [['I0', 10, 333], ['I1', 110, 5], ['I2', -100, 1000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1', 'I2']}, {'buckets': [0, 0, 0, 333, 0], 'required': 133, 'adjustment': 938, 'net_ar': 200}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 54, 150], ['I1', 71, 4000], ['I2', 70, 2500], ['I3', 110, 150], ['I4', 99, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I3']}, {'buckets': [0, 6505, 150, 0, 0], 'required': 348, 'adjustment': -2, 'net_ar': 6307}], ['control 1', {'as_of': 100, 'invoices': [['I0', 69, 4000], ['I1', 110, 4000], ['I2', 55, 1000], ['I3', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [4000, 0, 5000, 0, 0], 'required': 790, 'adjustment': 4790, 'net_ar': 8210}], ['control 2', {'as_of': 100, 'invoices': [['I0', 100, 4000], ['I1', 69, 1000], ['I2', 55, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [4000, 5000, 0], 'required': 705, 'adjustment': 505, 'net_ar': 8295}], ['control 3', {'as_of': 100, 'invoices': [['I0', 70, 4000], ['I1', 54, 1000], ['I2', 70, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 4005, 1000, 0, 0], 'required': 350, 'adjustment': 150, 'net_ar': 4655}], ['control 4', {'as_of': 100, 'invoices': [['I0', 110, 5], ['I1', 10, 5], ['I2', 100, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0', 'I2']}, {'buckets': [0, 0, 0, 5, 0], 'required': 2, 'adjustment': 2657, 'net_ar': 3}], ['control 5', {'as_of': 100, 'invoices': [['I0', 10, 1000], ['I1', 10, 150], ['I2', 39, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 0, 5000, 0], 'required': 2000, 'adjustment': 1950, 'net_ar': 3000}], ['control 6', {'as_of': 100, 'invoices': [['I0', 70, 5], ['I1', 100, 4000], ['I2', 99, 5], ['I3', 54, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I3']}, {'buckets': [4000, 5, 0, 0, 0], 'required': 40, 'adjustment': 50, 'net_ar': 3965}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 110, 150], ['I1', 10, 1000], ['I2', 70, 150], ['I3', 99, 1000], ['I4', 100, 2500], ['I5', 55, 333], ['I6', 54, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5', 'I6']}, {'buckets': [2650, 1150, 0, 1000, 0], 'required': 485, 'adjustment': 968, 'net_ar': 4315}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', 54, 1000], ['I1', 100, 5], ['I2', 70, 150], ['I3', 110, 150], ['I4', 100, 2500], ['I5', -100, 333], ['I6', 100, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': []}, {'buckets': [2805, 150, 1000, 0, 333], 'required': 436, 'adjustment': 436, 'net_ar': 3852}], ['control 1', {'as_of': 100, 'invoices': [['I0', 110, 2500], ['I1', 69, 150], ['I2', 54, 2500], ['I3', 10, 333]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [2500, 0, 2500, 333, 0], 'required': 533, 'adjustment': 483, 'net_ar': 4800}], ['control 2', {'as_of': 100, 'invoices': [['I0', 69, 2500], ['I1', 69, 150], ['I2', 55, 5], ['I3', 71, 1000], ['I4', 55, 4000], ['I5', -100, 2500], ['I6', 69, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': []}, {'buckets': [0, 1000, 10655, 0, 2500], 'required': 3523, 'adjustment': 3023, 'net_ar': 10632}], ['control 3', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 9, 1000], ['I2', -100, 2500], ['I3', -100, 150], ['I4', 70, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I0']}, {'buckets': [0, 4000, 3650], 'required': 2325, 'adjustment': 6325, 'net_ar': 5325}], ['control 4', {'as_of': 100, 'invoices': [['I0', -100, 2500], ['I1', 54, 4000], ['I2', 55, 4000], ['I3', 9, 1000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 4000, 7500], 'required': 4250, 'adjustment': 4400, 'net_ar': 7250}], ['control 5', {'as_of': 100, 'invoices': [['I0', 39, 333], ['I1', 39, 1000], ['I2', 100, 150], ['I3', 54, 4000], ['I4', -100, 5], ['I5', 71, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I5']}, {'buckets': [150, 0, 5338], 'required': 2672, 'adjustment': 2822, 'net_ar': 2816}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 70, 4000], ['I1', 70, 2500], ['I2', 100, 4000], ['I3', 71, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [4000, 4005, 0], 'required': 581, 'adjustment': 3081, 'net_ar': 7424}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', -100, 4000], ['I1', 9, 4000], ['I2', 110, 1000], ['I3', 100, 333], ['I4', 9, 5], ['I5', 99, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I5']}, {'buckets': [1333, 0, 0, 0, 8005], 'required': 6017, 'adjustment': 6317, 'net_ar': 3321}], ['control 1', {'as_of': 100, 'invoices': [['I0', 39, 5], ['I1', 99, 4000], ['I2', 55, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I1']}, {'buckets': [0, 0, 4000, 0, 0], 'required': 600, 'adjustment': 4605, 'net_ar': 3400}], ['control 2', {'as_of': 100, 'invoices': [['I0', 54, 5], ['I1', 40, 5], ['I2', 99, 333], ['I3', 71, 150], ['I4', 54, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 483, 4010], 'required': 2065, 'adjustment': 2065, 'net_ar': 2428}], ['control 3', {'as_of': 100, 'invoices': [['I0', -100, 2500], ['I1', 39, 4000], ['I2', 55, 1000], ['I3', 40, 4000], ['I4', 40, 4000], ['I5', 54, 2500], ['I6', 99, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5']}, {'buckets': [0, 4000, 9000, 4000, 2500], 'required': 5025, 'adjustment': 7525, 'net_ar': 14475}], ['control 4', {'as_of': 100, 'invoices': [['I0', 55, 5], ['I1', 100, 150], ['I2', 99, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I1', 'I2']}, {'buckets': [0, 0, 0, 0, 0], 'required': 0, 'adjustment': 305, 'net_ar': 0}], ['control 5', {'as_of': 100, 'invoices': [['I0', 39, 2500], ['I1', 39, 150], ['I2', 10, 4000], ['I3', 9, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 0, 0, 6650, 2500], 'required': 4535, 'adjustment': 4335, 'net_ar': 4615}]]]
for label, args, expected in fixtures[N-1]:
    try:
        actual = solve(args)
    except Exception as exc:
        actual = 'raised ' + type(exc).__name__
    check(label, actual, 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
regression: per-bucket rounding	`{'adjustment': 11536, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 1952, 'required': 5036}`	`{'adjustment': 11535, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 1953, 'required': 5035}`	Failed
control 1	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	Passed
control 2	`{'adjustment': 2840, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 3658, 'required': 1352}`	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 3660, 'required': 1350}`	Failed
control 3	`{'adjustment': 3300, 'buckets': [0, 0, 4000, 1000, 0], 'net_ar': 4000, 'required': 1000}`	`{'adjustment': 3300, 'buckets': [0, 0, 4000, 1000, 0], 'net_ar': 4000, 'required': 1000}`	Passed
control 4	`{'adjustment': 2250, 'buckets': [0, 4000, 3500], 'net_ar': 5250, 'required': 2250}`	`{'adjustment': 2250, 'buckets': [0, 4000, 3500], 'net_ar': 5250, 'required': 2250}`	Passed
control 5	`{'adjustment': 2975, 'buckets': [0, 0, 2500, 4000, 0], 'net_ar': 4525, 'required': 1975}`	`{'adjustment': 2975, 'buckets': [0, 0, 2500, 4000, 0], 'net_ar': 4525, 'required': 1975}`	Passed
control 6	`{'adjustment': 1308, 'buckets': [0, 0, 6500, 0, 0], 'net_ar': 5525, 'required': 975}`	`{'adjustment': 1308, 'buckets': [0, 0, 6500, 0, 0], 'net_ar': 5525, 'required': 975}`	Passed

SHA-256 / 7203d112c2e432bc88b773452989d95490b0daba1b1666efacfd85b3525ef726

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    wo = set(x['writeoffs'])
    allowance = x['allowance']
    buckets = [0] * len(x['rates'])
    for iid, due, amt in x['invoices']:
        if iid in wo:
            allowance -= amt
            continue
        past = max(0, x['as_of'] - due)
        for k, (limit, bp) in enumerate(x['rates']):
            if limit is None or past <= limit:
                buckets[k] += amt
                break
    required = 0
    for total, (limit, bp) in zip(buckets, x['rates']):
        q, r = divmod(total * bp, 10000)
        required += q + (1 if 2 * r >= 10000 else 0)
    ar = sum(buckets)
    return {'buckets': buckets, 'required': required, 'adjustment': required - allowance, 'net_ar': ar - required}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', -100, 5], ['I1', 39, 333], ['I2', 9, 2500], ['I3', -100, 4000], ['I4', 69, 150], ['I5', 70, 2500], ['I6', 55, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5', 'I6']}, {'buckets': [0, 0, 150, 333, 6505], 'required': 5035, 'adjustment': 11535, 'net_ar': 1953}], ['control 1', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 110, 150], ['I2', 100, 4000], ['I3', 40, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [4150, 0, 8000], 'required': 4083, 'adjustment': 4083, 'net_ar': 8067}], ['control 2', {'as_of': 100, 'invoices': [['I0', 70, 1000], ['I1', 99, 5], ['I2', 99, 5], ['I3', 110, 5], ['I4', -100, 333], ['I5', -100, 1000], ['I6', 54, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0', 'I1', 'I4']}, {'buckets': [5, 5, 4000, 0, 1000], 'required': 1350, 'adjustment': 2838, 'net_ar': 3660}], ['control 3', {'as_of': 100, 'invoices': [['I0', 10, 1000], ['I1', 110, 2500], ['I2', 69, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 4000, 1000, 0], 'required': 1000, 'adjustment': 3300, 'net_ar': 4000}], ['control 4', {'as_of': 100, 'invoices': [['I0', 40, 2500], ['I1', 99, 4000], ['I2', 9, 1000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 4000, 3500], 'required': 2250, 'adjustment': 2250, 'net_ar': 5250}], ['control 5', {'as_of': 100, 'invoices': [['I0', 55, 2500], ['I1', 71, 1000], ['I2', 10, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [0, 0, 2500, 4000, 0], 'required': 1975, 'adjustment': 2975, 'net_ar': 4525}], ['control 6', {'as_of': 100, 'invoices': [['I0', 55, 4000], ['I1', 54, 333], ['I2', 40, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [0, 0, 6500, 0, 0], 'required': 975, 'adjustment': 1308, 'net_ar': 5525}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 99, 2500], ['I1', 69, 1000], ['I2', 55, 333], ['I3', 39, 1000], ['I4', 39, 333], ['I5', 40, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1', 'I4', 'I5']}, {'buckets': [0, 2500, 333, 1000, 0], 'required': 575, 'adjustment': 5708, 'net_ar': 3258}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', 54, 2500], ['I1', 55, 5], ['I2', 10, 1000], ['I3', 71, 333], ['I4', 71, 1000], ['I5', 100, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': ['I2', 'I5']}, {'buckets': [0, 1338, 2500], 'required': 1417, 'adjustment': 2572, 'net_ar': 2421}], ['control 1', {'as_of': 100, 'invoices': [['I0', -100, 150], ['I1', 40, 1000], ['I2', 40, 5], ['I3', 39, 1000], ['I4', 9, 150], ['I5', 10, 1000], ['I6', 10, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': ['I2', 'I5']}, {'buckets': [0, 0, 2450], 'required': 1225, 'adjustment': 2030, 'net_ar': 1225}], ['control 2', {'as_of': 100, 'invoices': [['I0', 54, 1000], ['I1', 69, 333], ['I2', 55, 150], ['I3', 70, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 633, 1000], 'required': 579, 'adjustment': 379, 'net_ar': 1054}], ['control 3', {'as_of': 100, 'invoices': [['I0', 55, 333], ['I1', 10, 150], ['I2', 99, 1000], ['I3', 54, 5], ['I4', 69, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0']}, {'buckets': [0, 1000, 155, 150, 0], 'required': 133, 'adjustment': 266, 'net_ar': 1172}], ['control 4', {'as_of': 100, 'invoices': [['I0', 9, 1000], ['I1', 55, 2500], ['I2', 110, 2500], ['I3', 70, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [2500, 2500, 2500, 0, 1000], 'required': 1275, 'adjustment': 1425, 'net_ar': 7225}], ['control 5', {'as_of': 100, 'invoices': [['I0', 10, 333], ['I1', 110, 5], ['I2', -100, 1000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1', 'I2']}, {'buckets': [0, 0, 0, 333, 0], 'required': 133, 'adjustment': 938, 'net_ar': 200}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 54, 150], ['I1', 71, 4000], ['I2', 70, 2500], ['I3', 110, 150], ['I4', 99, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I3']}, {'buckets': [0, 6505, 150, 0, 0], 'required': 348, 'adjustment': -2, 'net_ar': 6307}], ['control 1', {'as_of': 100, 'invoices': [['I0', 69, 4000], ['I1', 110, 4000], ['I2', 55, 1000], ['I3', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [4000, 0, 5000, 0, 0], 'required': 790, 'adjustment': 4790, 'net_ar': 8210}], ['control 2', {'as_of': 100, 'invoices': [['I0', 100, 4000], ['I1', 69, 1000], ['I2', 55, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [4000, 5000, 0], 'required': 705, 'adjustment': 505, 'net_ar': 8295}], ['control 3', {'as_of': 100, 'invoices': [['I0', 70, 4000], ['I1', 54, 1000], ['I2', 70, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 4005, 1000, 0, 0], 'required': 350, 'adjustment': 150, 'net_ar': 4655}], ['control 4', {'as_of': 100, 'invoices': [['I0', 110, 5], ['I1', 10, 5], ['I2', 100, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0', 'I2']}, {'buckets': [0, 0, 0, 5, 0], 'required': 2, 'adjustment': 2657, 'net_ar': 3}], ['control 5', {'as_of': 100, 'invoices': [['I0', 10, 1000], ['I1', 10, 150], ['I2', 39, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 0, 5000, 0], 'required': 2000, 'adjustment': 1950, 'net_ar': 3000}], ['control 6', {'as_of': 100, 'invoices': [['I0', 70, 5], ['I1', 100, 4000], ['I2', 99, 5], ['I3', 54, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I3']}, {'buckets': [4000, 5, 0, 0, 0], 'required': 40, 'adjustment': 50, 'net_ar': 3965}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 110, 150], ['I1', 10, 1000], ['I2', 70, 150], ['I3', 99, 1000], ['I4', 100, 2500], ['I5', 55, 333], ['I6', 54, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5', 'I6']}, {'buckets': [2650, 1150, 0, 1000, 0], 'required': 485, 'adjustment': 968, 'net_ar': 4315}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', 54, 1000], ['I1', 100, 5], ['I2', 70, 150], ['I3', 110, 150], ['I4', 100, 2500], ['I5', -100, 333], ['I6', 100, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': []}, {'buckets': [2805, 150, 1000, 0, 333], 'required': 436, 'adjustment': 436, 'net_ar': 3852}], ['control 1', {'as_of': 100, 'invoices': [['I0', 110, 2500], ['I1', 69, 150], ['I2', 54, 2500], ['I3', 10, 333]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [2500, 0, 2500, 333, 0], 'required': 533, 'adjustment': 483, 'net_ar': 4800}], ['control 2', {'as_of': 100, 'invoices': [['I0', 69, 2500], ['I1', 69, 150], ['I2', 55, 5], ['I3', 71, 1000], ['I4', 55, 4000], ['I5', -100, 2500], ['I6', 69, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': []}, {'buckets': [0, 1000, 10655, 0, 2500], 'required': 3523, 'adjustment': 3023, 'net_ar': 10632}], ['control 3', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 9, 1000], ['I2', -100, 2500], ['I3', -100, 150], ['I4', 70, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I0']}, {'buckets': [0, 4000, 3650], 'required': 2325, 'adjustment': 6325, 'net_ar': 5325}], ['control 4', {'as_of': 100, 'invoices': [['I0', -100, 2500], ['I1', 54, 4000], ['I2', 55, 4000], ['I3', 9, 1000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 4000, 7500], 'required': 4250, 'adjustment': 4400, 'net_ar': 7250}], ['control 5', {'as_of': 100, 'invoices': [['I0', 39, 333], ['I1', 39, 1000], ['I2', 100, 150], ['I3', 54, 4000], ['I4', -100, 5], ['I5', 71, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I5']}, {'buckets': [150, 0, 5338], 'required': 2672, 'adjustment': 2822, 'net_ar': 2816}]], [['regression: per-bucket rounding', {'as_of': 100, 'invoices': [['I0', 70, 4000], ['I1', 70, 2500], ['I2', 100, 4000], ['I3', 71, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': ['I1']}, {'buckets': [4000, 4005, 0], 'required': 581, 'adjustment': 3081, 'net_ar': 7424}], ['regression: per-bucket rounding, partial-repair probe', {'as_of': 100, 'invoices': [['I0', -100, 4000], ['I1', 9, 4000], ['I2', 110, 1000], ['I3', 100, 333], ['I4', 9, 5], ['I5', 99, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I5']}, {'buckets': [1333, 0, 0, 0, 8005], 'required': 6017, 'adjustment': 6317, 'net_ar': 3321}], ['control 1', {'as_of': 100, 'invoices': [['I0', 39, 5], ['I1', 99, 4000], ['I2', 55, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I1']}, {'buckets': [0, 0, 4000, 0, 0], 'required': 600, 'adjustment': 4605, 'net_ar': 3400}], ['control 2', {'as_of': 100, 'invoices': [['I0', 54, 5], ['I1', 40, 5], ['I2', 99, 333], ['I3', 71, 150], ['I4', 54, 4000]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 483, 4010], 'required': 2065, 'adjustment': 2065, 'net_ar': 2428}], ['control 3', {'as_of': 100, 'invoices': [['I0', -100, 2500], ['I1', 39, 4000], ['I2', 55, 1000], ['I3', 40, 4000], ['I4', 40, 4000], ['I5', 54, 2500], ['I6', 99, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I5']}, {'buckets': [0, 4000, 9000, 4000, 2500], 'required': 5025, 'adjustment': 7525, 'net_ar': 14475}], ['control 4', {'as_of': 100, 'invoices': [['I0', 55, 5], ['I1', 100, 150], ['I2', 99, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': ['I0', 'I1', 'I2']}, {'buckets': [0, 0, 0, 0, 0], 'required': 0, 'adjustment': 305, 'net_ar': 0}], ['control 5', {'as_of': 100, 'invoices': [['I0', 39, 2500], ['I1', 39, 150], ['I2', 10, 4000], ['I3', 9, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': []}, {'buckets': [0, 0, 0, 6650, 2500], 'required': 4535, 'adjustment': 4335, 'net_ar': 4615}]]]
for label, args, expected in fixtures[N-1]:
    try:
        actual = solve(args)
    except Exception as exc:
        actual = 'raised ' + type(exc).__name__
    check(label, actual, 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
regression: per-bucket rounding	`{'adjustment': 11535, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 1953, 'required': 5035}`	`{'adjustment': 11535, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 1953, 'required': 5035}`	Passed
control 1	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	Passed
control 2	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 3660, 'required': 1350}`	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 3660, 'required': 1350}`	Passed
control 3	`{'adjustment': 3300, 'buckets': [0, 0, 4000, 1000, 0], 'net_ar': 4000, 'required': 1000}`	`{'adjustment': 3300, 'buckets': [0, 0, 4000, 1000, 0], 'net_ar': 4000, 'required': 1000}`	Passed
control 4	`{'adjustment': 2250, 'buckets': [0, 4000, 3500], 'net_ar': 5250, 'required': 2250}`	`{'adjustment': 2250, 'buckets': [0, 4000, 3500], 'net_ar': 5250, 'required': 2250}`	Passed
control 5	`{'adjustment': 2975, 'buckets': [0, 0, 2500, 4000, 0], 'net_ar': 4525, 'required': 1975}`	`{'adjustment': 2975, 'buckets': [0, 0, 2500, 4000, 0], 'net_ar': 4525, 'required': 1975}`	Passed
control 6	`{'adjustment': 1308, 'buckets': [0, 0, 6500, 0, 0], 'net_ar': 5525, 'required': 975}`	`{'adjustment': 1308, 'buckets': [0, 0, 6500, 0, 0], 'net_ar': 5525, 'required': 975}`	Passed

SHA-256 / 52eb053f91eef86cd2528bfde1af7372ad374105a66e69d1a15187a64b1a40a1

Verification & scope

A deterministic bounded teaching model with stipulated toy bookkeeping rules stated in the contract; amounts are integer cents; it makes no claim of conformance to any accounting standard or product. 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 2026-09-29T14:46:23.850539+00:00.

Case digest / 2882076ec753ea79d396036b6770e7cd5ceaeb6b24d22dc11ee0abbb7c397be0