{"abstract":"A fraction left over from Monday pays out on Tuesday.","category":"Currency rounding and FX conversion","checks":7,"contract":"solve(items, rate): items are [day, amount] with integer source minor units (reversals negative) in posting order; rate is target minor units per source minor unit. Within a day, each posting's converted amount is floor(cumulative_exact) - floor(previous cumulative_exact), so daily converted postings sum to floor of the day's exact converted total. The carry (cumulative total and previous floor) resets whenever the day changes. Return the list of integer converted postings.","contract_signature":"items, rate","evaluation_group":"w2-currency_rounding_and_fx_conversion-micro-payment-cumulative-carry","failed_approach":"Comparing only the year-month prefix of the day still carries remainders across days in the same month.","family":"w2-currency_rounding_and_fx_conversion-micro-payment-cumulative-carry-daily-reset","id":"FA-62201","implementations":{"attempt":{"sha256":"f438cdc7a01f3d750663a455e07ddbe7c3741416309df8d20a7f1513da997a53","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom decimal import Decimal, ROUND_HALF_EVEN, ROUND_HALF_UP, ROUND_FLOOR, ROUND_CEILING, ROUND_DOWN, ROUND_UP, ROUND_HALF_DOWN\nN = 1\nobservations = []\ndef solve(items, rate):\n    out, cum, prev_floor, day = [], Decimal(0), 0, None\n    r = Decimal(rate)\n    for d, a in items:\n        if day is None or d[:7] != day[:7]:\n            day, cum, prev_floor = d, Decimal(0), 0\n        cum += Decimal(a) * r\n        f = int(cum.to_integral_value(rounding=ROUND_FLOOR))\n        out.append(f - prev_floor)\n        prev_floor = f\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression daily-reset 1', ([['2026-03-01', 1], ['2026-03-02', 1], ['2026-03-02', 1]], '0.6'), [0, 0, 1]),\n  ('regression daily-reset 2', ([['d1', 1], ['d2', 1], ['d2', 1]], '0.6'), [0, 0, 1]),\n  ('partial repair guard 2',\n   ([['2026-03-01', -18], ['2026-03-01', 240], ['2026-03-02', -19], ['2026-03-02', 81], ['2026-03-02', 129],\n     ['2026-03-02', 231]],\n    '0.2472'),\n   [-5, 59, -5, 20, 32, 57]),\n  ('control: three micro postings', ([['d1', 1], ['d1', 1], ['d1', 1]], '0.4'), [0, 0, 1]),\n  ('control: reversal', ([['d1', 5], ['d1', -3]], '0.5'), [2, -1]),\n  ('control: single large', ([['2026-03-01', 12345]], '0.9215'), [11375]),\n  ('control: month change', ([['2026-03-31', 3], ['2026-04-01', 3]], '0.35'), [1, 1])],\n [('regression daily-reset 1',\n   ([['2026-03-01', -18], ['2026-03-01', 240], ['2026-03-02', -19], ['2026-03-02', 81], ['2026-03-02', 129],\n     ['2026-03-02', 231]],\n    '0.2472'),\n   [-5, 59, -5, 20, 32, 57]),\n  ('regression daily-reset 2',\n   ([['2026-03-02', 92], ['2026-03-03', 36], ['2026-03-03', -15], ['2026-04-01', 46], ['2026-04-01', 50],\n     ['2026-04-01', 95]],\n    '4.346'),\n   [399, 156, -65, 199, 218, 413]),\n  ('partial repair guard 2',\n   ([['2026-03-02', 62], ['2026-03-02', 120], ['2026-03-03', 27], ['2026-03-03', 189]], '0.4750'), [29, 57, 12, 90]),\n  ('control: single large', ([['2026-03-01', 12345]], '0.9215'), [11375]),\n  ('control: month change', ([['2026-03-31', 3], ['2026-04-01', 3]], '0.35'), [1, 1]),\n  ('control: empty', ([], '1.5'), []),\n  ('control: negative first', ([['d1', -1], ['d1', -1], ['d1', 2]], '0.3'), [-1, 0, 1])],\n [('regression daily-reset 1',\n   ([['2026-03-02', 62], ['2026-03-02', 120], ['2026-03-03', 27], ['2026-03-03', 189]], '0.4750'), [29, 57, 12, 90]),\n  ('regression daily-reset 2',\n   ([['2026-03-01', -26], ['2026-03-01', 4], ['2026-03-01', -3], ['2026-03-02', 57], ['2026-03-02', 131]], '5.53'),\n   [-144, 22, -17, 315, 724]),\n  ('partial repair guard 2',\n   ([['2026-03-01', 59], ['2026-03-02', 159], ['2026-03-02', 71], ['2026-03-03', 89]], '26.15'),\n   [1542, 4157, 1857, 2327]),\n  ('control: negative first', ([['d1', -1], ['d1', -1], ['d1', 2]], '0.3'), [-1, 0, 1]),\n  ('control: three micro postings', ([['d1', 1], ['d1', 1], ['d1', 1]], '0.4'), [0, 0, 1]),\n  ('control: day reset', ([['d1', 1], ['d2', 1], ['d2', 1]], '0.6'), [0, 0, 1]),\n  ('control: reversal', ([['d1', 5], ['d1', -3]], '0.5'), [2, -1])],\n [('regression daily-reset 1',\n   ([['2026-03-01', 59], ['2026-03-02', 159], ['2026-03-02', 71], ['2026-03-03', 89]], '26.15'),\n   [1542, 4157, 1857, 2327]),\n  ('regression daily-reset 2', ([['2026-03-01', -26], ['2026-03-02', 215]], '27.52'), [-716, 5916]),\n  ('partial repair guard 2',\n   ([['2026-03-02', 39], ['2026-03-02', 262], ['2026-03-02', -11], ['2026-03-03', 235], ['2026-03-03', -7],\n     ['2026-03-03', 97]],\n    '4.821'),\n   [188, 1263, -53, 1132, -33, 467]),\n  ('control: reversal', ([['d1', 5], ['d1', -3]], '0.5'), [2, -1]),\n  ('control: single large', ([['2026-03-01', 12345]], '0.9215'), [11375]),\n  ('control: month change', ([['2026-03-31', 3], ['2026-04-01', 3]], '0.35'), [1, 1]),\n  ('control: empty', ([], '1.5'), [])],\n [('regression daily-reset 1',\n   ([['2026-03-02', 39], ['2026-03-02', 262], ['2026-03-02', -11], ['2026-03-03', 235], ['2026-03-03', -7],\n     ['2026-03-03', 97]],\n    '4.821'),\n   [188, 1263, -53, 1132, -33, 467]),\n  ('regression daily-reset 2',\n   ([['2026-03-01', 42], ['2026-03-02', 162], ['2026-03-02', 1], ['2026-03-02', 28], ['2026-03-03', 127],\n     ['2026-03-03', -4]],\n    '0.0325'),\n   [1, 5, 0, 1, 4, -1]),\n  ('partial repair guard 2', ([['2026-03-01', 296], ['2026-03-02', 52]], '2.581'), [763, 134]),\n  ('control: empty', ([], '1.5'), []),\n  ('control: negative first', ([['d1', -1], ['d1', -1], ['d1', 2]], '0.3'), [-1, 0, 1]),\n  ('control: three micro postings', ([['d1', 1], ['d1', 1], ['d1', 1]], '0.4'), [0, 0, 1]),\n  ('control: day reset', ([['d1', 1], ['d2', 1], ['d2', 1]], '0.6'), [0, 0, 1])]]\nfor label, args, expected in cases[N - 1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"c0d33e349d332dc1d3536c3ef2acce2de99665b7a1cb0cfee301e52f6f691dda","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom decimal import Decimal, ROUND_HALF_EVEN, ROUND_HALF_UP, ROUND_FLOOR, ROUND_CEILING, ROUND_DOWN, ROUND_UP, ROUND_HALF_DOWN\nN = 1\nobservations = []\ndef solve(items, rate):\n    out, cum, prev_floor, day = [], Decimal(0), 0, None\n    r = Decimal(rate)\n    for d, a in items:\n        if day is None:\n            day, cum, prev_floor = d, Decimal(0), 0\n        cum += Decimal(a) * r\n        f = int(cum.to_integral_value(rounding=ROUND_FLOOR))\n        out.append(f - prev_floor)\n        prev_floor = f\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression daily-reset 1', ([['2026-03-01', 1], ['2026-03-02', 1], ['2026-03-02', 1]], '0.6'), [0, 0, 1]),\n  ('regression daily-reset 2', ([['d1', 1], ['d2', 1], ['d2', 1]], '0.6'), [0, 0, 1]),\n  ('partial repair guard 2',\n   ([['2026-03-01', -18], ['2026-03-01', 240], ['2026-03-02', -19], ['2026-03-02', 81], ['2026-03-02', 129],\n     ['2026-03-02', 231]],\n    '0.2472'),\n   [-5, 59, -5, 20, 32, 57]),\n  ('control: three micro postings', ([['d1', 1], ['d1', 1], ['d1', 1]], '0.4'), [0, 0, 1]),\n  ('control: reversal', ([['d1', 5], ['d1', -3]], '0.5'), [2, -1]),\n  ('control: single large', ([['2026-03-01', 12345]], '0.9215'), [11375]),\n  ('control: month change', ([['2026-03-31', 3], ['2026-04-01', 3]], '0.35'), [1, 1])],\n [('regression daily-reset 1',\n   ([['2026-03-01', -18], ['2026-03-01', 240], ['2026-03-02', -19], ['2026-03-02', 81], ['2026-03-02', 129],\n     ['2026-03-02', 231]],\n    '0.2472'),\n   [-5, 59, -5, 20, 32, 57]),\n  ('regression daily-reset 2',\n   ([['2026-03-02', 92], ['2026-03-03', 36], ['2026-03-03', -15], ['2026-04-01', 46], ['2026-04-01', 50],\n     ['2026-04-01', 95]],\n    '4.346'),\n   [399, 156, -65, 199, 218, 413]),\n  ('partial repair guard 2',\n   ([['2026-03-02', 62], ['2026-03-02', 120], ['2026-03-03', 27], ['2026-03-03', 189]], '0.4750'), [29, 57, 12, 90]),\n  ('control: single large', ([['2026-03-01', 12345]], '0.9215'), [11375]),\n  ('control: month change', ([['2026-03-31', 3], ['2026-04-01', 3]], '0.35'), [1, 1]),\n  ('control: empty', ([], '1.5'), []),\n  ('control: negative first', ([['d1', -1], ['d1', -1], ['d1', 2]], '0.3'), [-1, 0, 1])],\n [('regression daily-reset 1',\n   ([['2026-03-02', 62], ['2026-03-02', 120], ['2026-03-03', 27], ['2026-03-03', 189]], '0.4750'), [29, 57, 12, 90]),\n  ('regression daily-reset 2',\n   ([['2026-03-01', -26], ['2026-03-01', 4], ['2026-03-01', -3], ['2026-03-02', 57], ['2026-03-02', 131]], '5.53'),\n   [-144, 22, -17, 315, 724]),\n  ('partial repair guard 2',\n   ([['2026-03-01', 59], ['2026-03-02', 159], ['2026-03-02', 71], ['2026-03-03', 89]], '26.15'),\n   [1542, 4157, 1857, 2327]),\n  ('control: negative first', ([['d1', -1], ['d1', -1], ['d1', 2]], '0.3'), [-1, 0, 1]),\n  ('control: three micro postings', ([['d1', 1], ['d1', 1], ['d1', 1]], '0.4'), [0, 0, 1]),\n  ('control: day reset', ([['d1', 1], ['d2', 1], ['d2', 1]], '0.6'), [0, 0, 1]),\n  ('control: reversal', ([['d1', 5], ['d1', -3]], '0.5'), [2, -1])],\n [('regression daily-reset 1',\n   ([['2026-03-01', 59], ['2026-03-02', 159], ['2026-03-02', 71], ['2026-03-03', 89]], '26.15'),\n   [1542, 4157, 1857, 2327]),\n  ('regression daily-reset 2', ([['2026-03-01', -26], ['2026-03-02', 215]], '27.52'), [-716, 5916]),\n  ('partial repair guard 2',\n   ([['2026-03-02', 39], ['2026-03-02', 262], ['2026-03-02', -11], ['2026-03-03', 235], ['2026-03-03', -7],\n     ['2026-03-03', 97]],\n    '4.821'),\n   [188, 1263, -53, 1132, -33, 467]),\n  ('control: reversal', ([['d1', 5], ['d1', -3]], '0.5'), [2, -1]),\n  ('control: single large', ([['2026-03-01', 12345]], '0.9215'), [11375]),\n  ('control: month change', ([['2026-03-31', 3], ['2026-04-01', 3]], '0.35'), [1, 1]),\n  ('control: empty', ([], '1.5'), [])],\n [('regression daily-reset 1',\n   ([['2026-03-02', 39], ['2026-03-02', 262], ['2026-03-02', -11], ['2026-03-03', 235], ['2026-03-03', -7],\n     ['2026-03-03', 97]],\n    '4.821'),\n   [188, 1263, -53, 1132, -33, 467]),\n  ('regression daily-reset 2',\n   ([['2026-03-01', 42], ['2026-03-02', 162], ['2026-03-02', 1], ['2026-03-02', 28], ['2026-03-03', 127],\n     ['2026-03-03', -4]],\n    '0.0325'),\n   [1, 5, 0, 1, 4, -1]),\n  ('partial repair guard 2', ([['2026-03-01', 296], ['2026-03-02', 52]], '2.581'), [763, 134]),\n  ('control: empty', ([], '1.5'), []),\n  ('control: negative first', ([['d1', -1], ['d1', -1], ['d1', 2]], '0.3'), [-1, 0, 1]),\n  ('control: three micro postings', ([['d1', 1], ['d1', 1], ['d1', 1]], '0.4'), [0, 0, 1]),\n  ('control: day reset', ([['d1', 1], ['d2', 1], ['d2', 1]], '0.6'), [0, 0, 1])]]\nfor label, args, expected in cases[N - 1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"A deterministic, bounded teaching model with a stipulated toy contract; it makes no claim of conformance to any real regulation, standard, or institution's rules. 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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-currency_rounding_and_fx_conversion-micro-payment-cumulative-carry-daily-reset","generated_at":"2026-09-29T14:47:02.389876+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Currency amounts must be rounded at the right stage and in the right unit, or ledgers, quotes and settlements drift by minor units.","root_cause":"The day-change branch only runs for the first item.","sha256":"5bd173de3ba136ec4fd265f0e1cfd292bdfa10bf49fa294bfb4367f938de32b3","title":"The conversion carry is never reset between days · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":42.086,"exit_code":1,"observations":[{"actual":[0,1,0],"check":"regression daily-reset 1","expected":[0,0,1],"passed":false},{"actual":[0,0,1],"check":"regression daily-reset 2","expected":[0,0,1],"passed":true},{"actual":[-5,59,-4,20,32,57],"check":"partial repair guard 2","expected":[-5,59,-5,20,32,57],"passed":false},{"actual":[0,0,1],"check":"control: three micro postings","expected":[0,0,1],"passed":true},{"actual":[2,-1],"check":"control: reversal","expected":[2,-1],"passed":true},{"actual":[11375],"check":"control: single large","expected":[11375],"passed":true},{"actual":[1,1],"check":"control: month change","expected":[1,1],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression daily-reset 1\", \"actual\": [0, 1, 0], \"expected\": [0, 0, 1], \"passed\": false}, {\"check\": \"regression daily-reset 2\", \"actual\": [0, 0, 1], \"expected\": [0, 0, 1], \"passed\": true}, {\"check\": \"partial repair guard 2\", \"actual\": [-5, 59, -4, 20, 32, 57], \"expected\": [-5, 59, -5, 20, 32, 57], \"passed\": false}, {\"check\": \"control: three micro postings\", \"actual\": [0, 0, 1], \"expected\": [0, 0, 1], \"passed\": true}, {\"check\": \"control: reversal\", \"actual\": [2, -1], \"expected\": [2, -1], \"passed\": true}, {\"check\": \"control: single large\", \"actual\": [11375], \"expected\": [11375], \"passed\": true}, {\"check\": \"control: month change\", \"actual\": [1, 1], \"expected\": [1, 1], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.643,"exit_code":1,"observations":[{"actual":[0,1,0],"check":"regression daily-reset 1","expected":[0,0,1],"passed":false},{"actual":[0,1,0],"check":"regression daily-reset 2","expected":[0,0,1],"passed":false},{"actual":[-5,59,-4,20,32,57],"check":"partial repair guard 2","expected":[-5,59,-5,20,32,57],"passed":false},{"actual":[0,0,1],"check":"control: three micro postings","expected":[0,0,1],"passed":true},{"actual":[2,-1],"check":"control: reversal","expected":[2,-1],"passed":true},{"actual":[11375],"check":"control: single large","expected":[11375],"passed":true},{"actual":[1,1],"check":"control: month change","expected":[1,1],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression daily-reset 1\", \"actual\": [0, 1, 0], \"expected\": [0, 0, 1], \"passed\": false}, {\"check\": \"regression daily-reset 2\", \"actual\": [0, 1, 0], \"expected\": [0, 0, 1], \"passed\": false}, {\"check\": \"partial repair guard 2\", \"actual\": [-5, 59, -4, 20, 32, 57], \"expected\": [-5, 59, -5, 20, 32, 57], \"passed\": false}, {\"check\": \"control: three micro postings\", \"actual\": [0, 0, 1], \"expected\": [0, 0, 1], \"passed\": true}, {\"check\": \"control: reversal\", \"actual\": [2, -1], \"expected\": [2, -1], \"passed\": true}, {\"check\": \"control: single large\", \"actual\": [11375], \"expected\": [11375], \"passed\": true}, {\"check\": \"control: month change\", \"actual\": [1, 1], \"expected\": [1, 1], \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}