FA-67531 / Elevator dispatch scheduling / Open access

Hall call waiting time statistics: mean rounding · case 01

The mean wait is one second high.

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

ROOT CAUSE

The mean is rounded to nearest instead of floored.

VERIFIED REPAIR

Floor the mean wait.

Unsuccessful approach: Ceiling division always rounds a fractional mean up.

Case contract

Each hall call has a registration time and an answer time (None if still unanswered at end_s). Waits are answer - registration clamped at zero (clock skew); unanswered calls count with the censored wait end_s - registration. Report the integer mean (floor), per-mille of waits over 60 s (floor), the maximum and the count; all zeros when there are no calls.

Why this case matters

Lift group controllers make these decisions many times per minute; a wrong answer strands passengers, wastes trips or overrides a safety rule.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(x):
    waits = []
    for reg, ans in x['calls']:
        if ans is None:
            waits.append(x['end_s'] - reg)
        else:
            waits.append(max(0, ans - reg))
    if not waits:
        return {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}
    longs = sum(1 for w in waits if w > 60)
    return {'avg': round(sum(waits) / len(waits)), 'long_permille': longs * 1000 // len(waits), 'max': max(waits), 'count': len(waits)}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('sampled regression 9', {'end_s': 600, 'calls': [[575, 595], [530, None], [76, None], [511, None], [173, 178], [76, 137], [46, 51], [370, 520]]}, {'avg': 115, 'long_permille': 625, 'max': 524, 'count': 8}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 1', {'end_s': 600, 'calls': [[93, 138], [499, 519], [546, None], [485, None], [376, 526], [329, 419], [42, None], [303, None]]}, {'avg': 166, 'long_permille': 625, 'max': 558, 'count': 8}), ('control 4', {'end_s': 600, 'calls': [[15, None], [80, 100], [304, 324], [560, 557], [73, 78], [574, None]]}, {'avg': 109, 'long_permille': 166, 'max': 585, 'count': 6}), ('sampled regression 7', {'end_s': 600, 'calls': [[196, 216], [228, 248], [100, None], [381, 471], [370, 415], [56, 76]]}, {'avg': 115, 'long_permille': 333, 'max': 500, 'count': 6})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('sampled regression 27', {'end_s': 600, 'calls': [[441, None], [579, None], [47, 137], [447, None]]}, {'avg': 105, 'long_permille': 750, 'max': 159, 'count': 4}), ('control 6', {'end_s': 600, 'calls': [[541, None], [503, 502], [554, None], [543, None], [284, 434]]}, {'avg': 62, 'long_permille': 200, 'max': 150, 'count': 5}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('control 12', {'end_s': 600, 'calls': [[549, None], [34, 94], [153, 243]]}, {'avg': 67, 'long_permille': 333, 'max': 90, 'count': 3}), ('sampled regression 15', {'end_s': 600, 'calls': [[427, 472], [290, 440], [125, None], [18, 79], [88, 178], [156, 306], [7, None], [120, None]]}, {'avg': 255, 'long_permille': 875, 'max': 593, 'count': 8}), ('control 18', {'end_s': 600, 'calls': [[508, 528]]}, {'avg': 20, 'long_permille': 0, 'max': 20, 'count': 1})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('sampled regression 61', {'end_s': 600, 'calls': [[410, 415], [504, 564], [213, 258], [291, None], [359, None], [364, 369], [125, None]]}, {'avg': 162, 'long_permille': 428, 'max': 475, 'count': 7}), ('control 13', {'end_s': 600, 'calls': [[451, 511], [494, 539], [553, None], [26, None], [306, 367], [164, 314], [548, None], [406, 556]]}, {'avg': 142, 'long_permille': 500, 'max': 574, 'count': 8}), ('boundary: no calls', {'end_s': 600, 'calls': []}, {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 23', {'end_s': 600, 'calls': [[121, 141], [388, None], [577, None]]}, {'avg': 85, 'long_permille': 333, 'max': 212, 'count': 3}), ('control 26', {'end_s': 600, 'calls': [[205, 225], [336, 381]]}, {'avg': 32, 'long_permille': 0, 'max': 45, 'count': 2}), ('sampled regression 29', {'end_s': 600, 'calls': [[26, 31], [282, 287], [487, 577], [127, 187], [568, None], [130, 280], [335, 395], [184, 274]]}, {'avg': 61, 'long_permille': 375, 'max': 150, 'count': 8})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('sampled regression 9', {'end_s': 600, 'calls': [[575, 595], [530, None], [76, None], [511, None], [173, 178], [76, 137], [46, 51], [370, 520]]}, {'avg': 115, 'long_permille': 625, 'max': 524, 'count': 8}), ('sampled regression 20', {'end_s': 600, 'calls': [[520, None], [447, 467], [161, 221], [506, 511], [146, 296], [576, None], [73, 223], [194, 214]]}, {'avg': 63, 'long_permille': 375, 'max': 150, 'count': 8}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 34', {'end_s': 600, 'calls': [[526, 531], [100, 160], [338, None], [152, 242], [413, 433], [56, 117]]}, {'avg': 83, 'long_permille': 500, 'max': 262, 'count': 6}), ('control 37', {'end_s': 600, 'calls': [[542, 547], [483, None], [421, 418], [216, None]]}, {'avg': 126, 'long_permille': 500, 'max': 384, 'count': 4}), ('control 40', {'end_s': 600, 'calls': [[286, 346], [342, None], [309, 308], [91, 96], [519, 524], [518, None], [12, 73]]}, {'avg': 67, 'long_permille': 428, 'max': 258, 'count': 7})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('sampled regression 27', {'end_s': 600, 'calls': [[441, None], [579, None], [47, 137], [447, None]]}, {'avg': 105, 'long_permille': 750, 'max': 159, 'count': 4}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('boundary: no calls', {'end_s': 600, 'calls': []}, {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}), ('control 45', {'end_s': 600, 'calls': [[54, 204], [360, None], [102, None], [487, None], [396, None]]}, {'avg': 241, 'long_permille': 1000, 'max': 498, 'count': 5}), ('sampled regression 48', {'end_s': 600, 'calls': [[235, 234], [112, 202], [453, 498], [10, 30], [166, 186], [359, 358], [466, 471]]}, {'avg': 25, 'long_permille': 142, 'max': 90, 'count': 7}), ('sampled regression 51', {'end_s': 600, 'calls': [[553, None], [377, 422], [370, None], [180, 241]]}, {'avg': 95, 'long_permille': 500, 'max': 230, 'count': 4})]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: mean with a remainder	`{'avg': 11, 'count': 3, 'long_permille': 0, 'max': 11}`	`{'avg': 10, 'count': 3, 'long_permille': 0, 'max': 11}`	Failed
boundary: wait of exactly sixty seconds	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 61}`	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 61}`	Passed
sampled regression 9	`{'avg': 116, 'count': 8, 'long_permille': 625, 'max': 524}`	`{'avg': 115, 'count': 8, 'long_permille': 625, 'max': 524}`	Failed
boundary: long unanswered call	`{'avg': 73, 'count': 3, 'long_permille': 333, 'max': 200}`	`{'avg': 73, 'count': 3, 'long_permille': 333, 'max': 200}`	Passed
boundary: unanswered call at the end	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 100}`	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 100}`	Passed
control 1	`{'avg': 166, 'count': 8, 'long_permille': 625, 'max': 558}`	`{'avg': 166, 'count': 8, 'long_permille': 625, 'max': 558}`	Passed
control 4	`{'avg': 109, 'count': 6, 'long_permille': 166, 'max': 585}`	`{'avg': 109, 'count': 6, 'long_permille': 166, 'max': 585}`	Passed
sampled regression 7	`{'avg': 116, 'count': 6, 'long_permille': 333, 'max': 500}`	`{'avg': 115, 'count': 6, 'long_permille': 333, 'max': 500}`	Failed

SHA-256 / 656f06aa9d7fa9bf2d2858cde4acce908abb8d2867240c66763c14b549f56c71

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    waits = []
    for reg, ans in x['calls']:
        if ans is None:
            waits.append(x['end_s'] - reg)
        else:
            waits.append(max(0, ans - reg))
    if not waits:
        return {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}
    longs = sum(1 for w in waits if w > 60)
    return {'avg': -(-sum(waits) // len(waits)), 'long_permille': longs * 1000 // len(waits), 'max': max(waits), 'count': len(waits)}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('sampled regression 9', {'end_s': 600, 'calls': [[575, 595], [530, None], [76, None], [511, None], [173, 178], [76, 137], [46, 51], [370, 520]]}, {'avg': 115, 'long_permille': 625, 'max': 524, 'count': 8}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 1', {'end_s': 600, 'calls': [[93, 138], [499, 519], [546, None], [485, None], [376, 526], [329, 419], [42, None], [303, None]]}, {'avg': 166, 'long_permille': 625, 'max': 558, 'count': 8}), ('control 4', {'end_s': 600, 'calls': [[15, None], [80, 100], [304, 324], [560, 557], [73, 78], [574, None]]}, {'avg': 109, 'long_permille': 166, 'max': 585, 'count': 6}), ('sampled regression 7', {'end_s': 600, 'calls': [[196, 216], [228, 248], [100, None], [381, 471], [370, 415], [56, 76]]}, {'avg': 115, 'long_permille': 333, 'max': 500, 'count': 6})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('sampled regression 27', {'end_s': 600, 'calls': [[441, None], [579, None], [47, 137], [447, None]]}, {'avg': 105, 'long_permille': 750, 'max': 159, 'count': 4}), ('control 6', {'end_s': 600, 'calls': [[541, None], [503, 502], [554, None], [543, None], [284, 434]]}, {'avg': 62, 'long_permille': 200, 'max': 150, 'count': 5}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('control 12', {'end_s': 600, 'calls': [[549, None], [34, 94], [153, 243]]}, {'avg': 67, 'long_permille': 333, 'max': 90, 'count': 3}), ('sampled regression 15', {'end_s': 600, 'calls': [[427, 472], [290, 440], [125, None], [18, 79], [88, 178], [156, 306], [7, None], [120, None]]}, {'avg': 255, 'long_permille': 875, 'max': 593, 'count': 8}), ('control 18', {'end_s': 600, 'calls': [[508, 528]]}, {'avg': 20, 'long_permille': 0, 'max': 20, 'count': 1})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('sampled regression 61', {'end_s': 600, 'calls': [[410, 415], [504, 564], [213, 258], [291, None], [359, None], [364, 369], [125, None]]}, {'avg': 162, 'long_permille': 428, 'max': 475, 'count': 7}), ('control 13', {'end_s': 600, 'calls': [[451, 511], [494, 539], [553, None], [26, None], [306, 367], [164, 314], [548, None], [406, 556]]}, {'avg': 142, 'long_permille': 500, 'max': 574, 'count': 8}), ('boundary: no calls', {'end_s': 600, 'calls': []}, {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 23', {'end_s': 600, 'calls': [[121, 141], [388, None], [577, None]]}, {'avg': 85, 'long_permille': 333, 'max': 212, 'count': 3}), ('control 26', {'end_s': 600, 'calls': [[205, 225], [336, 381]]}, {'avg': 32, 'long_permille': 0, 'max': 45, 'count': 2}), ('sampled regression 29', {'end_s': 600, 'calls': [[26, 31], [282, 287], [487, 577], [127, 187], [568, None], [130, 280], [335, 395], [184, 274]]}, {'avg': 61, 'long_permille': 375, 'max': 150, 'count': 8})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('sampled regression 9', {'end_s': 600, 'calls': [[575, 595], [530, None], [76, None], [511, None], [173, 178], [76, 137], [46, 51], [370, 520]]}, {'avg': 115, 'long_permille': 625, 'max': 524, 'count': 8}), ('sampled regression 20', {'end_s': 600, 'calls': [[520, None], [447, 467], [161, 221], [506, 511], [146, 296], [576, None], [73, 223], [194, 214]]}, {'avg': 63, 'long_permille': 375, 'max': 150, 'count': 8}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 34', {'end_s': 600, 'calls': [[526, 531], [100, 160], [338, None], [152, 242], [413, 433], [56, 117]]}, {'avg': 83, 'long_permille': 500, 'max': 262, 'count': 6}), ('control 37', {'end_s': 600, 'calls': [[542, 547], [483, None], [421, 418], [216, None]]}, {'avg': 126, 'long_permille': 500, 'max': 384, 'count': 4}), ('control 40', {'end_s': 600, 'calls': [[286, 346], [342, None], [309, 308], [91, 96], [519, 524], [518, None], [12, 73]]}, {'avg': 67, 'long_permille': 428, 'max': 258, 'count': 7})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('sampled regression 27', {'end_s': 600, 'calls': [[441, None], [579, None], [47, 137], [447, None]]}, {'avg': 105, 'long_permille': 750, 'max': 159, 'count': 4}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('boundary: no calls', {'end_s': 600, 'calls': []}, {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}), ('control 45', {'end_s': 600, 'calls': [[54, 204], [360, None], [102, None], [487, None], [396, None]]}, {'avg': 241, 'long_permille': 1000, 'max': 498, 'count': 5}), ('sampled regression 48', {'end_s': 600, 'calls': [[235, 234], [112, 202], [453, 498], [10, 30], [166, 186], [359, 358], [466, 471]]}, {'avg': 25, 'long_permille': 142, 'max': 90, 'count': 7}), ('sampled regression 51', {'end_s': 600, 'calls': [[553, None], [377, 422], [370, None], [180, 241]]}, {'avg': 95, 'long_permille': 500, 'max': 230, 'count': 4})]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: mean with a remainder	`{'avg': 11, 'count': 3, 'long_permille': 0, 'max': 11}`	`{'avg': 10, 'count': 3, 'long_permille': 0, 'max': 11}`	Failed
boundary: wait of exactly sixty seconds	`{'avg': 61, 'count': 2, 'long_permille': 500, 'max': 61}`	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 61}`	Failed
sampled regression 9	`{'avg': 116, 'count': 8, 'long_permille': 625, 'max': 524}`	`{'avg': 115, 'count': 8, 'long_permille': 625, 'max': 524}`	Failed
boundary: long unanswered call	`{'avg': 74, 'count': 3, 'long_permille': 333, 'max': 200}`	`{'avg': 73, 'count': 3, 'long_permille': 333, 'max': 200}`	Failed
boundary: unanswered call at the end	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 100}`	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 100}`	Passed
control 1	`{'avg': 167, 'count': 8, 'long_permille': 625, 'max': 558}`	`{'avg': 166, 'count': 8, 'long_permille': 625, 'max': 558}`	Failed
control 4	`{'avg': 110, 'count': 6, 'long_permille': 166, 'max': 585}`	`{'avg': 109, 'count': 6, 'long_permille': 166, 'max': 585}`	Failed
sampled regression 7	`{'avg': 116, 'count': 6, 'long_permille': 333, 'max': 500}`	`{'avg': 115, 'count': 6, 'long_permille': 333, 'max': 500}`	Failed

SHA-256 / 6ae0f95572fd3e6c43a23937caf187350a3285d279347685229c57c1cf91f08f

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(x):
    waits = []
    for reg, ans in x['calls']:
        if ans is None:
            waits.append(x['end_s'] - reg)
        else:
            waits.append(max(0, ans - reg))
    if not waits:
        return {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}
    longs = sum(1 for w in waits if w > 60)
    return {'avg': sum(waits) // len(waits), 'long_permille': longs * 1000 // len(waits), 'max': max(waits), 'count': len(waits)}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('sampled regression 9', {'end_s': 600, 'calls': [[575, 595], [530, None], [76, None], [511, None], [173, 178], [76, 137], [46, 51], [370, 520]]}, {'avg': 115, 'long_permille': 625, 'max': 524, 'count': 8}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 1', {'end_s': 600, 'calls': [[93, 138], [499, 519], [546, None], [485, None], [376, 526], [329, 419], [42, None], [303, None]]}, {'avg': 166, 'long_permille': 625, 'max': 558, 'count': 8}), ('control 4', {'end_s': 600, 'calls': [[15, None], [80, 100], [304, 324], [560, 557], [73, 78], [574, None]]}, {'avg': 109, 'long_permille': 166, 'max': 585, 'count': 6}), ('sampled regression 7', {'end_s': 600, 'calls': [[196, 216], [228, 248], [100, None], [381, 471], [370, 415], [56, 76]]}, {'avg': 115, 'long_permille': 333, 'max': 500, 'count': 6})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('sampled regression 27', {'end_s': 600, 'calls': [[441, None], [579, None], [47, 137], [447, None]]}, {'avg': 105, 'long_permille': 750, 'max': 159, 'count': 4}), ('control 6', {'end_s': 600, 'calls': [[541, None], [503, 502], [554, None], [543, None], [284, 434]]}, {'avg': 62, 'long_permille': 200, 'max': 150, 'count': 5}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('control 12', {'end_s': 600, 'calls': [[549, None], [34, 94], [153, 243]]}, {'avg': 67, 'long_permille': 333, 'max': 90, 'count': 3}), ('sampled regression 15', {'end_s': 600, 'calls': [[427, 472], [290, 440], [125, None], [18, 79], [88, 178], [156, 306], [7, None], [120, None]]}, {'avg': 255, 'long_permille': 875, 'max': 593, 'count': 8}), ('control 18', {'end_s': 600, 'calls': [[508, 528]]}, {'avg': 20, 'long_permille': 0, 'max': 20, 'count': 1})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('sampled regression 61', {'end_s': 600, 'calls': [[410, 415], [504, 564], [213, 258], [291, None], [359, None], [364, 369], [125, None]]}, {'avg': 162, 'long_permille': 428, 'max': 475, 'count': 7}), ('control 13', {'end_s': 600, 'calls': [[451, 511], [494, 539], [553, None], [26, None], [306, 367], [164, 314], [548, None], [406, 556]]}, {'avg': 142, 'long_permille': 500, 'max': 574, 'count': 8}), ('boundary: no calls', {'end_s': 600, 'calls': []}, {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 23', {'end_s': 600, 'calls': [[121, 141], [388, None], [577, None]]}, {'avg': 85, 'long_permille': 333, 'max': 212, 'count': 3}), ('control 26', {'end_s': 600, 'calls': [[205, 225], [336, 381]]}, {'avg': 32, 'long_permille': 0, 'max': 45, 'count': 2}), ('sampled regression 29', {'end_s': 600, 'calls': [[26, 31], [282, 287], [487, 577], [127, 187], [568, None], [130, 280], [335, 395], [184, 274]]}, {'avg': 61, 'long_permille': 375, 'max': 150, 'count': 8})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('sampled regression 9', {'end_s': 600, 'calls': [[575, 595], [530, None], [76, None], [511, None], [173, 178], [76, 137], [46, 51], [370, 520]]}, {'avg': 115, 'long_permille': 625, 'max': 524, 'count': 8}), ('sampled regression 20', {'end_s': 600, 'calls': [[520, None], [447, 467], [161, 221], [506, 511], [146, 296], [576, None], [73, 223], [194, 214]]}, {'avg': 63, 'long_permille': 375, 'max': 150, 'count': 8}), ('boundary: unanswered call at the end', {'end_s': 600, 'calls': [[500, None], [10, 30]]}, {'avg': 60, 'long_permille': 500, 'max': 100, 'count': 2}), ('control 34', {'end_s': 600, 'calls': [[526, 531], [100, 160], [338, None], [152, 242], [413, 433], [56, 117]]}, {'avg': 83, 'long_permille': 500, 'max': 262, 'count': 6}), ('control 37', {'end_s': 600, 'calls': [[542, 547], [483, None], [421, 418], [216, None]]}, {'avg': 126, 'long_permille': 500, 'max': 384, 'count': 4}), ('control 40', {'end_s': 600, 'calls': [[286, 346], [342, None], [309, 308], [91, 96], [519, 524], [518, None], [12, 73]]}, {'avg': 67, 'long_permille': 428, 'max': 258, 'count': 7})], [('regression: mean with a remainder', {'end_s': 600, 'calls': [[0, 10], [0, 11], [0, 11]]}, {'avg': 10, 'long_permille': 0, 'max': 11, 'count': 3}), ('boundary: long unanswered call', {'end_s': 600, 'calls': [[400, None], [0, 10], [5, 15]]}, {'avg': 73, 'long_permille': 333, 'max': 200, 'count': 3}), ('sampled regression 27', {'end_s': 600, 'calls': [[441, None], [579, None], [47, 137], [447, None]]}, {'avg': 105, 'long_permille': 750, 'max': 159, 'count': 4}), ('boundary: wait of exactly sixty seconds', {'end_s': 600, 'calls': [[0, 60], [100, 161]]}, {'avg': 60, 'long_permille': 500, 'max': 61, 'count': 2}), ('boundary: no calls', {'end_s': 600, 'calls': []}, {'avg': 0, 'long_permille': 0, 'max': 0, 'count': 0}), ('control 45', {'end_s': 600, 'calls': [[54, 204], [360, None], [102, None], [487, None], [396, None]]}, {'avg': 241, 'long_permille': 1000, 'max': 498, 'count': 5}), ('sampled regression 48', {'end_s': 600, 'calls': [[235, 234], [112, 202], [453, 498], [10, 30], [166, 186], [359, 358], [466, 471]]}, {'avg': 25, 'long_permille': 142, 'max': 90, 'count': 7}), ('sampled regression 51', {'end_s': 600, 'calls': [[553, None], [377, 422], [370, None], [180, 241]]}, {'avg': 95, 'long_permille': 500, 'max': 230, 'count': 4})]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: mean with a remainder	`{'avg': 10, 'count': 3, 'long_permille': 0, 'max': 11}`	`{'avg': 10, 'count': 3, 'long_permille': 0, 'max': 11}`	Passed
boundary: wait of exactly sixty seconds	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 61}`	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 61}`	Passed
sampled regression 9	`{'avg': 115, 'count': 8, 'long_permille': 625, 'max': 524}`	`{'avg': 115, 'count': 8, 'long_permille': 625, 'max': 524}`	Passed
boundary: long unanswered call	`{'avg': 73, 'count': 3, 'long_permille': 333, 'max': 200}`	`{'avg': 73, 'count': 3, 'long_permille': 333, 'max': 200}`	Passed
boundary: unanswered call at the end	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 100}`	`{'avg': 60, 'count': 2, 'long_permille': 500, 'max': 100}`	Passed
control 1	`{'avg': 166, 'count': 8, 'long_permille': 625, 'max': 558}`	`{'avg': 166, 'count': 8, 'long_permille': 625, 'max': 558}`	Passed
control 4	`{'avg': 109, 'count': 6, 'long_permille': 166, 'max': 585}`	`{'avg': 109, 'count': 6, 'long_permille': 166, 'max': 585}`	Passed
sampled regression 7	`{'avg': 115, 'count': 6, 'long_permille': 333, 'max': 500}`	`{'avg': 115, 'count': 6, 'long_permille': 333, 'max': 500}`	Passed

SHA-256 / 47997b14972480e68446c1a71d37b57839d05c25444bd0abf505c8385da3fd29

Verification & scope

Stipulated toy lift-control contract for a bounded teaching model; it makes no claim of conformance to any lift code or vendor dispatcher and omits real safety cases. 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 2026-09-29T14:47:53.771195+00:00.

Case digest / fa3cca85cdebf1bfdc79bc2b5ed85dba4606cb687886e98c1b78cfd76680221a