FA-58146 / Double-entry ledger accounting / Open access

Aging-based allowance adjustment: net receivable base · case 01

Net receivables use the pre-adjustment allowance.

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ROOT CAUSE

Net AR subtracts the old allowance instead of the required allowance.

VERIFIED REPAIR

Report receivables net of the required allowance.

Unsuccessful approach: Summing all invoices includes the written-off receivables.

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 + (1 if 2 * r >= 10000 else 0)
    ar = sum(buckets)
    return {'buckets': buckets, 'required': required, 'adjustment': required - allowance, 'net_ar': ar - allowance}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 99, 4000], ['I1', 55, 150], ['I2', -100, 333], ['I3', 100, 150], ['I4', 100, 5], ['I5', 9, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I5']}, {'buckets': [155, 4000, 150, 0, 333], 'required': 475, 'adjustment': 4275, 'net_ar': 4163}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 39, 4000], ['I1', 10, 150], ['I2', 110, 5], ['I3', 40, 5], ['I4', 99, 150], ['I5', 54, 4000], ['I6', 54, 1000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I6']}, {'buckets': [5, 150, 4005, 4150, 0], 'required': 2269, 'adjustment': 2769, 'net_ar': 6041}], ['sample 3', {'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}], ['sample 4', {'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}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 55, 2500], ['I1', 99, 4000], ['I2', 99, 150], ['I3', 55, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0']}, {'buckets': [0, 4150, 5, 0, 0], 'required': 209, 'adjustment': 2509, 'net_ar': 3946}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 71, 4000], ['I1', 100, 333], ['I2', 100, 150], ['I3', 54, 5], ['I4', 39, 333]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': []}, {'buckets': [483, 4000, 338], 'required': 679, 'adjustment': 829, 'net_ar': 4142}]], [['regression: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 99, 5], ['I1', 39, 5], ['I2', 10, 150], ['I3', -100, 333], ['I4', 39, 1000], ['I5', 39, 4000], ['I6', 100, 2500]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': ['I2', 'I3']}, {'buckets': [2500, 5, 5005], 'required': 2554, 'adjustment': 3187, 'net_ar': 4956}], ['sample 2', {'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}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 55, 4000], ['I1', 40, 4000], ['I2', 40, 5], ['I3', 39, 4000], ['I4', 55, 1000], ['I5', 110, 150], ['I6', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I1']}, {'buckets': [4150, 0, 5005, 4000, 0], 'required': 2393, 'adjustment': 5893, 'net_ar': 10762}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 70, 5], ['I1', 69, 5], ['I2', 71, 333], ['I3', -100, 5], ['I4', 54, 333], ['I5', 100, 150], ['I6', 71, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0', 'I5']}, {'buckets': [0, 483, 338, 0, 5], 'required': 79, 'adjustment': 34, 'net_ar': 747}], ['sample 5', {'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}], ['sample 6', {'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}]], [['regression: net receivable base', {'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}], ['sample 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}], ['sample 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}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 69, 5], ['I2', 110, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [150, 0, 5, 4000, 0], 'required': 1603, 'adjustment': 1753, 'net_ar': 2552}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 100, 1000], ['I1', 54, 333], ['I2', 69, 1000], ['I3', 40, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [1000, 1000, 483], 'required': 387, 'adjustment': 187, 'net_ar': 2096}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 39, 2500], ['I1', 69, 150], ['I2', 55, 333]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 333, 2500, 0], 'required': 1050, 'adjustment': 1000, 'net_ar': 1783}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 100, 150], ['I1', 55, 150], ['I2', 40, 1000], ['I3', 10, 1000], ['I4', 10, 4000], ['I5', 10, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I1']}, {'buckets': [150, 0, 1000, 5150, 0], 'required': 2212, 'adjustment': 2512, 'net_ar': 4088}]], [['regression: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 70, 1000], ['I1', 10, 5], ['I2', 39, 150], ['I3', 54, 5], ['I4', 70, 2500], ['I5', 40, 150], ['I6', 39, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': ['I2', 'I4']}, {'buckets': [0, 1000, 165], 'required': 208, 'adjustment': 2658, 'net_ar': 957}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 69, 150], ['I1', 71, 150], ['I2', 70, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I2']}, {'buckets': [0, 150, 150, 0, 0], 'required': 31, 'adjustment': -319, 'net_ar': 269}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 40, 1000], ['I1', 40, 333], ['I2', 70, 1000], ['I3', 70, 4000], ['I4', 69, 333], ['I5', 10, 4000], ['I6', 9, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 5000, 1666, 4000, 2500], 'required': 3975, 'adjustment': 4125, 'net_ar': 9191}], ['sample 4', {'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}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 54, 5], ['I1', 100, 333], ['I2', -100, 4000], ['I3', 9, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [333, 0, 5, 0, 8000], 'required': 6004, 'adjustment': 6154, 'net_ar': 2334}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 71, 333], ['I1', 39, 150], ['I2', 71, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 4333, 0, 150, 0], 'required': 277, 'adjustment': 277, 'net_ar': 4206}]], [['regression: net receivable base', {'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}], ['control 1', {'as_of': 100, 'invoices': [['I0', 99, 1000], ['I1', 9, 333], ['I2', 70, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': []}, {'buckets': [0, 5000, 0, 0, 333], 'required': 500, 'adjustment': 0, 'net_ar': 4833}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 70, 2500], ['I1', 110, 4000], ['I2', -100, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 500, 'writeoffs': ['I2']}, {'buckets': [4000, 2500, 0], 'required': 393, 'adjustment': 43, 'net_ar': 6107}], ['sample 3', {'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}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 9, 150], ['I1', 9, 1000], ['I2', 54, 1000], ['I3', 99, 2500], ['I4', 69, 333], ['I5', 71, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 2505, 1333, 0, 1150], 'required': 1188, 'adjustment': 1338, 'net_ar': 3800}], ['sample 5', {'as_of': 100, 'invoices': [['I0', -100, 150], ['I1', 110, 150], ['I2', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0']}, {'buckets': [4150, 0, 0, 0, 0], 'required': 42, 'adjustment': 342, 'net_ar': 4108}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 40, 4000], ['I1', 39, 1000], ['I2', -100, 5], ['I3', 99, 5], ['I4', -100, 333], ['I5', 10, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I3']}, {'buckets': [0, 0, 4000, 5000, 338], 'required': 2854, 'adjustment': 2359, 'net_ar': 6484}]]]
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: net receivable base	`{'adjustment': 11535, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 13488, 'required': 5035}`	`{'adjustment': 11535, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 1953, 'required': 5035}`	Failed
sample 1	`{'adjustment': 4275, 'buckets': [155, 4000, 150, 0, 333], 'net_ar': 8438, 'required': 475}`	`{'adjustment': 4275, 'buckets': [155, 4000, 150, 0, 333], 'net_ar': 4163, 'required': 475}`	Failed
sample 2	`{'adjustment': 2769, 'buckets': [5, 150, 4005, 4150, 0], 'net_ar': 8810, 'required': 2269}`	`{'adjustment': 2769, 'buckets': [5, 150, 4005, 4150, 0], 'net_ar': 6041, 'required': 2269}`	Failed
sample 3	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 12150, 'required': 4083}`	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	Failed
sample 4	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 6498, 'required': 1350}`	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 3660, 'required': 1350}`	Failed
sample 5	`{'adjustment': 2509, 'buckets': [0, 4150, 5, 0, 0], 'net_ar': 6455, 'required': 209}`	`{'adjustment': 2509, 'buckets': [0, 4150, 5, 0, 0], 'net_ar': 3946, 'required': 209}`	Failed
sample 6	`{'adjustment': 829, 'buckets': [483, 4000, 338], 'net_ar': 4971, 'required': 679}`	`{'adjustment': 829, 'buckets': [483, 4000, 338], 'net_ar': 4142, 'required': 679}`	Failed

SHA-256 / d5e562c36eb103d53d00eb0db3825ccc5162793b3f98879e3a3d0d647e0c7b89

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 2 * r >= 10000 else 0)
    ar = sum(buckets)
    return {'buckets': buckets, 'required': required, 'adjustment': required - allowance, 'net_ar': sum(amt for _, _, amt in x['invoices']) - required}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 99, 4000], ['I1', 55, 150], ['I2', -100, 333], ['I3', 100, 150], ['I4', 100, 5], ['I5', 9, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I5']}, {'buckets': [155, 4000, 150, 0, 333], 'required': 475, 'adjustment': 4275, 'net_ar': 4163}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 39, 4000], ['I1', 10, 150], ['I2', 110, 5], ['I3', 40, 5], ['I4', 99, 150], ['I5', 54, 4000], ['I6', 54, 1000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I6']}, {'buckets': [5, 150, 4005, 4150, 0], 'required': 2269, 'adjustment': 2769, 'net_ar': 6041}], ['sample 3', {'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}], ['sample 4', {'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}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 55, 2500], ['I1', 99, 4000], ['I2', 99, 150], ['I3', 55, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0']}, {'buckets': [0, 4150, 5, 0, 0], 'required': 209, 'adjustment': 2509, 'net_ar': 3946}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 71, 4000], ['I1', 100, 333], ['I2', 100, 150], ['I3', 54, 5], ['I4', 39, 333]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': []}, {'buckets': [483, 4000, 338], 'required': 679, 'adjustment': 829, 'net_ar': 4142}]], [['regression: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 99, 5], ['I1', 39, 5], ['I2', 10, 150], ['I3', -100, 333], ['I4', 39, 1000], ['I5', 39, 4000], ['I6', 100, 2500]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': ['I2', 'I3']}, {'buckets': [2500, 5, 5005], 'required': 2554, 'adjustment': 3187, 'net_ar': 4956}], ['sample 2', {'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}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 55, 4000], ['I1', 40, 4000], ['I2', 40, 5], ['I3', 39, 4000], ['I4', 55, 1000], ['I5', 110, 150], ['I6', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I1']}, {'buckets': [4150, 0, 5005, 4000, 0], 'required': 2393, 'adjustment': 5893, 'net_ar': 10762}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 70, 5], ['I1', 69, 5], ['I2', 71, 333], ['I3', -100, 5], ['I4', 54, 333], ['I5', 100, 150], ['I6', 71, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0', 'I5']}, {'buckets': [0, 483, 338, 0, 5], 'required': 79, 'adjustment': 34, 'net_ar': 747}], ['sample 5', {'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}], ['sample 6', {'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}]], [['regression: net receivable base', {'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}], ['sample 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}], ['sample 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}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 69, 5], ['I2', 110, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [150, 0, 5, 4000, 0], 'required': 1603, 'adjustment': 1753, 'net_ar': 2552}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 100, 1000], ['I1', 54, 333], ['I2', 69, 1000], ['I3', 40, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [1000, 1000, 483], 'required': 387, 'adjustment': 187, 'net_ar': 2096}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 39, 2500], ['I1', 69, 150], ['I2', 55, 333]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 333, 2500, 0], 'required': 1050, 'adjustment': 1000, 'net_ar': 1783}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 100, 150], ['I1', 55, 150], ['I2', 40, 1000], ['I3', 10, 1000], ['I4', 10, 4000], ['I5', 10, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I1']}, {'buckets': [150, 0, 1000, 5150, 0], 'required': 2212, 'adjustment': 2512, 'net_ar': 4088}]], [['regression: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 70, 1000], ['I1', 10, 5], ['I2', 39, 150], ['I3', 54, 5], ['I4', 70, 2500], ['I5', 40, 150], ['I6', 39, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': ['I2', 'I4']}, {'buckets': [0, 1000, 165], 'required': 208, 'adjustment': 2658, 'net_ar': 957}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 69, 150], ['I1', 71, 150], ['I2', 70, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I2']}, {'buckets': [0, 150, 150, 0, 0], 'required': 31, 'adjustment': -319, 'net_ar': 269}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 40, 1000], ['I1', 40, 333], ['I2', 70, 1000], ['I3', 70, 4000], ['I4', 69, 333], ['I5', 10, 4000], ['I6', 9, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 5000, 1666, 4000, 2500], 'required': 3975, 'adjustment': 4125, 'net_ar': 9191}], ['sample 4', {'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}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 54, 5], ['I1', 100, 333], ['I2', -100, 4000], ['I3', 9, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [333, 0, 5, 0, 8000], 'required': 6004, 'adjustment': 6154, 'net_ar': 2334}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 71, 333], ['I1', 39, 150], ['I2', 71, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 4333, 0, 150, 0], 'required': 277, 'adjustment': 277, 'net_ar': 4206}]], [['regression: net receivable base', {'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}], ['control 1', {'as_of': 100, 'invoices': [['I0', 99, 1000], ['I1', 9, 333], ['I2', 70, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': []}, {'buckets': [0, 5000, 0, 0, 333], 'required': 500, 'adjustment': 0, 'net_ar': 4833}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 70, 2500], ['I1', 110, 4000], ['I2', -100, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 500, 'writeoffs': ['I2']}, {'buckets': [4000, 2500, 0], 'required': 393, 'adjustment': 43, 'net_ar': 6107}], ['sample 3', {'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}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 9, 150], ['I1', 9, 1000], ['I2', 54, 1000], ['I3', 99, 2500], ['I4', 69, 333], ['I5', 71, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 2505, 1333, 0, 1150], 'required': 1188, 'adjustment': 1338, 'net_ar': 3800}], ['sample 5', {'as_of': 100, 'invoices': [['I0', -100, 150], ['I1', 110, 150], ['I2', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0']}, {'buckets': [4150, 0, 0, 0, 0], 'required': 42, 'adjustment': 342, 'net_ar': 4108}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 40, 4000], ['I1', 39, 1000], ['I2', -100, 5], ['I3', 99, 5], ['I4', -100, 333], ['I5', 10, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I3']}, {'buckets': [0, 0, 4000, 5000, 338], 'required': 2854, 'adjustment': 2359, 'net_ar': 6484}]]]
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: net receivable base	`{'adjustment': 11535, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 8453, 'required': 5035}`	`{'adjustment': 11535, 'buckets': [0, 0, 150, 333, 6505], 'net_ar': 1953, 'required': 5035}`	Failed
sample 1	`{'adjustment': 4275, 'buckets': [155, 4000, 150, 0, 333], 'net_ar': 8163, 'required': 475}`	`{'adjustment': 4275, 'buckets': [155, 4000, 150, 0, 333], 'net_ar': 4163, 'required': 475}`	Failed
sample 2	`{'adjustment': 2769, 'buckets': [5, 150, 4005, 4150, 0], 'net_ar': 7041, 'required': 2269}`	`{'adjustment': 2769, 'buckets': [5, 150, 4005, 4150, 0], 'net_ar': 6041, 'required': 2269}`	Failed
sample 3	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	Passed
sample 4	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 4998, 'required': 1350}`	`{'adjustment': 2838, 'buckets': [5, 5, 4000, 0, 1000], 'net_ar': 3660, 'required': 1350}`	Failed
sample 5	`{'adjustment': 2509, 'buckets': [0, 4150, 5, 0, 0], 'net_ar': 6446, 'required': 209}`	`{'adjustment': 2509, 'buckets': [0, 4150, 5, 0, 0], 'net_ar': 3946, 'required': 209}`	Failed
sample 6	`{'adjustment': 829, 'buckets': [483, 4000, 338], 'net_ar': 4142, 'required': 679}`	`{'adjustment': 829, 'buckets': [483, 4000, 338], 'net_ar': 4142, 'required': 679}`	Passed

SHA-256 / b638d291fe88f9ec01eb92fde4c2cd868317d6f7ac84c0195c17912222427fb5

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: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 99, 4000], ['I1', 55, 150], ['I2', -100, 333], ['I3', 100, 150], ['I4', 100, 5], ['I5', 9, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I5']}, {'buckets': [155, 4000, 150, 0, 333], 'required': 475, 'adjustment': 4275, 'net_ar': 4163}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 39, 4000], ['I1', 10, 150], ['I2', 110, 5], ['I3', 40, 5], ['I4', 99, 150], ['I5', 54, 4000], ['I6', 54, 1000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I6']}, {'buckets': [5, 150, 4005, 4150, 0], 'required': 2269, 'adjustment': 2769, 'net_ar': 6041}], ['sample 3', {'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}], ['sample 4', {'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}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 55, 2500], ['I1', 99, 4000], ['I2', 99, 150], ['I3', 55, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0']}, {'buckets': [0, 4150, 5, 0, 0], 'required': 209, 'adjustment': 2509, 'net_ar': 3946}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 71, 4000], ['I1', 100, 333], ['I2', 100, 150], ['I3', 54, 5], ['I4', 39, 333]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': []}, {'buckets': [483, 4000, 338], 'required': 679, 'adjustment': 829, 'net_ar': 4142}]], [['regression: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 99, 5], ['I1', 39, 5], ['I2', 10, 150], ['I3', -100, 333], ['I4', 39, 1000], ['I5', 39, 4000], ['I6', 100, 2500]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': -150, 'writeoffs': ['I2', 'I3']}, {'buckets': [2500, 5, 5005], 'required': 2554, 'adjustment': 3187, 'net_ar': 4956}], ['sample 2', {'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}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 55, 4000], ['I1', 40, 4000], ['I2', 40, 5], ['I3', 39, 4000], ['I4', 55, 1000], ['I5', 110, 150], ['I6', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I1']}, {'buckets': [4150, 0, 5005, 4000, 0], 'required': 2393, 'adjustment': 5893, 'net_ar': 10762}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 70, 5], ['I1', 69, 5], ['I2', 71, 333], ['I3', -100, 5], ['I4', 54, 333], ['I5', 100, 150], ['I6', 71, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I0', 'I5']}, {'buckets': [0, 483, 338, 0, 5], 'required': 79, 'adjustment': 34, 'net_ar': 747}], ['sample 5', {'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}], ['sample 6', {'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}]], [['regression: net receivable base', {'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}], ['sample 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}], ['sample 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}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 10, 4000], ['I1', 69, 5], ['I2', 110, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [150, 0, 5, 4000, 0], 'required': 1603, 'adjustment': 1753, 'net_ar': 2552}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 100, 1000], ['I1', 54, 333], ['I2', 69, 1000], ['I3', 40, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': []}, {'buckets': [1000, 1000, 483], 'required': 387, 'adjustment': 187, 'net_ar': 2096}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 39, 2500], ['I1', 69, 150], ['I2', 55, 333]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 200, 'writeoffs': ['I1']}, {'buckets': [0, 0, 333, 2500, 0], 'required': 1050, 'adjustment': 1000, 'net_ar': 1783}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 100, 150], ['I1', 55, 150], ['I2', 40, 1000], ['I3', 10, 1000], ['I4', 10, 4000], ['I5', 10, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I1']}, {'buckets': [150, 0, 1000, 5150, 0], 'required': 2212, 'adjustment': 2512, 'net_ar': 4088}]], [['regression: net receivable base', {'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}], ['sample 1', {'as_of': 100, 'invoices': [['I0', 70, 1000], ['I1', 10, 5], ['I2', 39, 150], ['I3', 54, 5], ['I4', 70, 2500], ['I5', 40, 150], ['I6', 39, 5]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 200, 'writeoffs': ['I2', 'I4']}, {'buckets': [0, 1000, 165], 'required': 208, 'adjustment': 2658, 'net_ar': 957}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 69, 150], ['I1', 71, 150], ['I2', 70, 150]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I2']}, {'buckets': [0, 150, 150, 0, 0], 'required': 31, 'adjustment': -319, 'net_ar': 269}], ['sample 3', {'as_of': 100, 'invoices': [['I0', 40, 1000], ['I1', 40, 333], ['I2', 70, 1000], ['I3', 70, 4000], ['I4', 69, 333], ['I5', 10, 4000], ['I6', 9, 2500]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 5000, 1666, 4000, 2500], 'required': 3975, 'adjustment': 4125, 'net_ar': 9191}], ['sample 4', {'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}], ['sample 5', {'as_of': 100, 'invoices': [['I0', 54, 5], ['I1', 100, 333], ['I2', -100, 4000], ['I3', 9, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [333, 0, 5, 0, 8000], 'required': 6004, 'adjustment': 6154, 'net_ar': 2334}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 71, 333], ['I1', 39, 150], ['I2', 71, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 0, 'writeoffs': []}, {'buckets': [0, 4333, 0, 150, 0], 'required': 277, 'adjustment': 277, 'net_ar': 4206}]], [['regression: net receivable base', {'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}], ['control 1', {'as_of': 100, 'invoices': [['I0', 99, 1000], ['I1', 9, 333], ['I2', 70, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': []}, {'buckets': [0, 5000, 0, 0, 333], 'required': 500, 'adjustment': 0, 'net_ar': 4833}], ['sample 2', {'as_of': 100, 'invoices': [['I0', 70, 2500], ['I1', 110, 4000], ['I2', -100, 150]], 'rates': [[0, 200], [45, 1250], [None, 5000]], 'allowance': 500, 'writeoffs': ['I2']}, {'buckets': [4000, 2500, 0], 'required': 393, 'adjustment': 43, 'net_ar': 6107}], ['sample 3', {'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}], ['sample 4', {'as_of': 100, 'invoices': [['I0', 9, 150], ['I1', 9, 1000], ['I2', 54, 1000], ['I3', 99, 2500], ['I4', 69, 333], ['I5', 71, 5]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': []}, {'buckets': [0, 2505, 1333, 0, 1150], 'required': 1188, 'adjustment': 1338, 'net_ar': 3800}], ['sample 5', {'as_of': 100, 'invoices': [['I0', -100, 150], ['I1', 110, 150], ['I2', 100, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': -150, 'writeoffs': ['I0']}, {'buckets': [4150, 0, 0, 0, 0], 'required': 42, 'adjustment': 342, 'net_ar': 4108}], ['sample 6', {'as_of': 100, 'invoices': [['I0', 40, 4000], ['I1', 39, 1000], ['I2', -100, 5], ['I3', 99, 5], ['I4', -100, 333], ['I5', 10, 4000]], 'rates': [[0, 100], [30, 500], [60, 1500], [90, 4000], [None, 7500]], 'allowance': 500, 'writeoffs': ['I3']}, {'buckets': [0, 0, 4000, 5000, 338], 'required': 2854, 'adjustment': 2359, 'net_ar': 6484}]]]
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: net receivable base	`{'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
sample 1	`{'adjustment': 4275, 'buckets': [155, 4000, 150, 0, 333], 'net_ar': 4163, 'required': 475}`	`{'adjustment': 4275, 'buckets': [155, 4000, 150, 0, 333], 'net_ar': 4163, 'required': 475}`	Passed
sample 2	`{'adjustment': 2769, 'buckets': [5, 150, 4005, 4150, 0], 'net_ar': 6041, 'required': 2269}`	`{'adjustment': 2769, 'buckets': [5, 150, 4005, 4150, 0], 'net_ar': 6041, 'required': 2269}`	Passed
sample 3	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	`{'adjustment': 4083, 'buckets': [4150, 0, 8000], 'net_ar': 8067, 'required': 4083}`	Passed
sample 4	`{'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
sample 5	`{'adjustment': 2509, 'buckets': [0, 4150, 5, 0, 0], 'net_ar': 3946, 'required': 209}`	`{'adjustment': 2509, 'buckets': [0, 4150, 5, 0, 0], 'net_ar': 3946, 'required': 209}`	Passed
sample 6	`{'adjustment': 829, 'buckets': [483, 4000, 338], 'net_ar': 4142, 'required': 679}`	`{'adjustment': 829, 'buckets': [483, 4000, 338], 'net_ar': 4142, 'required': 679}`	Passed

SHA-256 / 87babad1f68b17f3288ebd3b6ec8b6e271454602d882c25e0c46631a67009802

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 2026-09-29T14:46:23.983918+00:00.

Case digest / 9488f8aed9df6c1dec31008c748785b84ceaaab54577934f2f746bdef07d5247