FA-67376 / Elevator dispatch scheduling / Open access

Destination dispatch allocation: load bookkeeping · case 01

A car keeps being allocated groups beyond its capacity.

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ROOT CAUSE

The allocated group is never added to the car load.

THE FAILURE

The allocated group is never added to the car load.

Unsuccessful approach: Counting one per request under-counts groups.

Case contract

Requests (destination, group size) are allocated one by one. A car is eligible if load + group size <= capacity. Cost = ready time + per_stop_s * existing stops + stop_penalty_s if the destination is not already a stop. The lowest cost wins, ties to the lowest car id. The chosen car adds the destination to its stops and the group to its load. None if no car is eligible.

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):
    cars = {c['id']: {'ready': c['ready_s'], 'stops': set(c['stops']), 'load': c['load'], 'cap': c['cap']} for c in x['cars']}
    out = []
    for req in x['requests']:
        best = None
        for cid in sorted(cars):
            c = cars[cid]
            if c['load'] + req['n'] > c['cap']:
                continue
            new_stop = 0 if req['dest'] in c['stops'] else 1
            cost = c['ready'] + x['per_stop_s'] * len(c['stops']) + x['stop_penalty_s'] * new_stop
            if best is None or cost < best[0]:
                best = (cost, cid)
        if best is None:
            out.append(None)
            continue
        c = cars[best[1]]
        c['stops'].add(req['dest'])
        out.append(best[1])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 9', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [3, 9], 'load': 4, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [8, 6, 12], 'load': 11, 'cap': 13}], 'requests': [{'dest': 10, 'n': 3}, {'dest': 3, 'n': 3}, {'dest': 13, 'n': 1}, {'dest': 2, 'n': 1}, {'dest': 5, 'n': 5}], 'stop_penalty_s': 10, 'per_stop_s': 3}, ['A', 'A', 'A', 'B', None]), ('sampled regression 3', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [8, 13, 9], 'load': 0, 'cap': 13}], 'requests': [{'dest': 13, 'n': 5}, {'dest': 11, 'n': 1}, {'dest': 12, 'n': 5}, {'dest': 3, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'B', 'B', 'B']), ('boundary: group exactly fills the car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 10, 'cap': 12}, {'id': 'B', 'ready_s': 30, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 5, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('boundary: coincident destination beats an idle car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [7], 'load': 0, 'cap': 12}], 'requests': [{'dest': 7, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['B']), ('sampled regression 1', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [10, 11], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [9], 'load': 11, 'cap': 12}, {'id': 'C', 'ready_s': 0, 'stops': [13, 14, 2], 'load': 11, 'cap': 13}], 'requests': [{'dest': 10, 'n': 1}, {'dest': 9, 'n': 5}], 'stop_penalty_s': 10, 'per_stop_s': 3}, ['A', None]), ('control 4', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 11, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [3], 'load': 4, 'cap': 12}, {'id': 'C', 'ready_s': 5, 'stops': [], 'load': 11, 'cap': 13}], 'requests': [{'dest': 7, 'n': 2}, {'dest': 3, 'n': 1}, {'dest': 8, 'n': 1}, {'dest': 3, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['C', 'B', 'A', 'B']), ('control 7', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [11, 6], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [7], 'load': 8, 'cap': 12}, {'id': 'C', 'ready_s': 10, 'stops': [5], 'load': 0, 'cap': 12}], 'requests': [{'dest': 2, 'n': 1}, {'dest': 8, 'n': 5}, {'dest': 11, 'n': 3}, {'dest': 3, 'n': 1}], 'stop_penalty_s': 15, 'per_stop_s': 5}, ['A', 'C', 'A', 'A'])], [('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 38', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 5, 'stops': [2, 13, 9], 'load': 0, 'cap': 13}], 'requests': [{'dest': 13, 'n': 1}, {'dest': 8, 'n': 2}, {'dest': 5, 'n': 3}, {'dest': 13, 'n': 3}, {'dest': 14, 'n': 5}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'A', 'B', 'B', 'B']), ('sampled regression 22', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [7, 5, 11], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'C', 'ready_s': 0, 'stops': [10, 8], 'load': 0, 'cap': 13}], 'requests': [{'dest': 12, 'n': 2}, {'dest': 11, 'n': 5}, {'dest': 13, 'n': 2}, {'dest': 13, 'n': 1}, {'dest': 7, 'n': 5}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['C', 'A', 'A', 'A', 'C']), ('boundary: empty car earns no discount', {'cars': [{'id': 'A', 'ready_s': 4, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [9], 'load': 0, 'cap': 12}], 'requests': [{'dest': 3, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('boundary: equal cost cars', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 5, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 4, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('control 12', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [6, 3], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 4, 'cap': 12}, {'id': 'C', 'ready_s': 20, 'stops': [10, 8], 'load': 11, 'cap': 13}], 'requests': [{'dest': 10, 'n': 1}, {'dest': 2, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'A']), ('control 15', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [3], 'load': 0, 'cap': 13}, {'id': 'B', 'ready_s': 5, 'stops': [7, 2], 'load': 0, 'cap': 13}, {'id': 'C', 'ready_s': 5, 'stops': [12], 'load': 0, 'cap': 12}], 'requests': [{'dest': 2, 'n': 3}, {'dest': 13, 'n': 5}, {'dest': 11, 'n': 1}, {'dest': 2, 'n': 1}, {'dest': 12, 'n': 3}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['B', 'A', 'C', 'B', 'C']), ('control 18', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [2, 7, 5], 'load': 0, 'cap': 12}], 'requests': [{'dest': 10, 'n': 5}, {'dest': 2, 'n': 1}, {'dest': 6, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'A'])], [('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 63', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 4, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [12, 11], 'load': 4, 'cap': 12}], 'requests': [{'dest': 3, 'n': 5}, {'dest': 4, 'n': 5}, {'dest': 11, 'n': 1}, {'dest': 14, 'n': 3}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'B', 'A', 'A']), ('sampled regression 42', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [3, 8, 13], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [6], 'load': 8, 'cap': 13}, {'id': 'C', 'ready_s': 5, 'stops': [12], 'load': 8, 'cap': 13}], 'requests': [{'dest': 10, 'n': 3}, {'dest': 12, 'n': 3}, {'dest': 3, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['C', 'A', 'A']), ('boundary: second group sees the first allocation', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 2, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 6, 'n': 3}, {'dest': 6, 'n': 3}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'A']), ('boundary: no eligible car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 11, 'cap': 12}], 'requests': [{'dest': 5, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, [None]), ('control 23', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [2], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [9, 8], 'load': 4, 'cap': 13}, {'id': 'C', 'ready_s': 10, 'stops': [], 'load': 0, 'cap': 13}], 'requests': [{'dest': 8, 'n': 3}, {'dest': 13, 'n': 1}, {'dest': 9, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['C', 'C', 'B']), ('sampled regression 26', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [9], 'load': 8, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [11, 14, 4], 'load': 8, 'cap': 13}], 'requests': [{'dest': 13, 'n': 1}, {'dest': 5, 'n': 1}, {'dest': 12, 'n': 1}, {'dest': 9, 'n': 1}, {'dest': 7, 'n': 3}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'A', 'A', 'B']), ('control 29', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 13}, {'id': 'B', 'ready_s': 10, 'stops': [2, 5, 7], 'load': 8, 'cap': 13}, {'id': 'C', 'ready_s': 20, 'stops': [2], 'load': 4, 'cap': 12}], 'requests': [{'dest': 6, 'n': 1}, {'dest': 3, 'n': 5}], 'stop_penalty_s': 15, 'per_stop_s': 5}, ['A', 'A'])], [('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 77', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [11, 9, 14], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [6, 3], 'load': 4, 'cap': 12}, {'id': 'C', 'ready_s': 0, 'stops': [5, 13, 12], 'load': 8, 'cap': 13}], 'requests': [{'dest': 5, 'n': 3}, {'dest': 2, 'n': 1}, {'dest': 14, 'n': 3}, {'dest': 5, 'n': 5}, {'dest': 5, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['C', 'C', 'A', 'B', 'C']), ('sampled regression 64', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [11, 7, 3], 'load': 8, 'cap': 13}, {'id': 'C', 'ready_s': 0, 'stops': [8, 3], 'load': 8, 'cap': 13}], 'requests': [{'dest': 6, 'n': 1}, {'dest': 3, 'n': 3}, {'dest': 7, 'n': 3}], 'stop_penalty_s': 8, 'per_stop_s': 5}, ['A', 'C', 'A']), ('boundary: no eligible car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 11, 'cap': 12}], 'requests': [{'dest': 5, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, [None]), ('boundary: group exactly fills the car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 10, 'cap': 12}, {'id': 'B', 'ready_s': 30, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 5, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('control 34', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [8], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 10, 'stops': [2], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 1}, {'dest': 11, 'n': 3}, {'dest': 5, 'n': 1}, {'dest': 9, 'n': 1}, {'dest': 10, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['B', 'B', 'A', 'B', 'A']), ('control 37', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 8, 'cap': 12}, {'id': 'B', 'ready_s': 5, 'stops': [9, 14, 8], 'load': 8, 'cap': 12}], 'requests': [{'dest': 5, 'n': 1}, {'dest': 8, 'n': 1}, {'dest': 2, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'B', 'A']), ('sampled regression 40', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 4, 'cap': 13}, {'id': 'B', 'ready_s': 0, 'stops': [10, 5, 7], 'load': 0, 'cap': 12}], 'requests': [{'dest': 5, 'n': 5}, {'dest': 5, 'n': 5}, {'dest': 7, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 5}, ['A', 'B', 'A'])], [('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 19', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 5, 'stops': [14, 11], 'load': 0, 'cap': 12}], 'requests': [{'dest': 13, 'n': 5}, {'dest': 7, 'n': 1}], 'stop_penalty_s': 15, 'per_stop_s': 5}, ['A', 'B']), ('sampled regression 3', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [8, 13, 9], 'load': 0, 'cap': 13}], 'requests': [{'dest': 13, 'n': 5}, {'dest': 11, 'n': 1}, {'dest': 12, 'n': 5}, {'dest': 3, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'B', 'B', 'B']), ('boundary: coincident destination beats an idle car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [7], 'load': 0, 'cap': 12}], 'requests': [{'dest': 7, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['B']), ('boundary: empty car earns no discount', {'cars': [{'id': 'A', 'ready_s': 4, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [9], 'load': 0, 'cap': 12}], 'requests': [{'dest': 3, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('control 45', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [5], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 5}, {'dest': 9, 'n': 5}, {'dest': 13, 'n': 1}, {'dest': 9, 'n': 2}, {'dest': 8, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['B', 'A', 'B', 'A', 'A']), ('control 48', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [7], 'load': 11, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [2, 13], 'load': 11, 'cap': 13}, {'id': 'C', 'ready_s': 20, 'stops': [10, 12], 'load': 11, 'cap': 12}], 'requests': [{'dest': 6, 'n': 2}, {'dest': 14, 'n': 5}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['B', None]), ('control 51', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [3], 'load': 8, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [12, 8], 'load': 0, 'cap': 12}, {'id': 'C', 'ready_s': 20, 'stops': [10], 'load': 0, 'cap': 13}], 'requests': [{'dest': 14, 'n': 1}, {'dest': 13, 'n': 2}, {'dest': 5, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 5}, ['A', 'A', 'A'])]]
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: capacity used up by earlier groups	`['A', 'A', 'A']`	`['A', 'A', 'B']`	Failed
sampled regression 9	`['A', 'A', 'A', 'B', 'A']`	`['A', 'A', 'A', 'B', None]`	Failed
sampled regression 3	`['A', 'A', 'A', 'A']`	`['A', 'B', 'B', 'B']`	Failed
boundary: group exactly fills the car	`['A']`	`['A']`	Passed
boundary: coincident destination beats an idle car	`['B']`	`['B']`	Passed
sampled regression 1	`['A', 'A']`	`['A', None]`	Failed
control 4	`['C', 'B', 'A', 'B']`	`['C', 'B', 'A', 'B']`	Passed
control 7	`['A', 'C', 'A', 'A']`	`['A', 'C', 'A', 'A']`	Passed

SHA-256 / 855551e40bfcfc5f35885a7103f6ecbcb7725470dca0451e3af56fc19f0fc591

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    cars = {c['id']: {'ready': c['ready_s'], 'stops': set(c['stops']), 'load': c['load'], 'cap': c['cap']} for c in x['cars']}
    out = []
    for req in x['requests']:
        best = None
        for cid in sorted(cars):
            c = cars[cid]
            if c['load'] + req['n'] > c['cap']:
                continue
            new_stop = 0 if req['dest'] in c['stops'] else 1
            cost = c['ready'] + x['per_stop_s'] * len(c['stops']) + x['stop_penalty_s'] * new_stop
            if best is None or cost < best[0]:
                best = (cost, cid)
        if best is None:
            out.append(None)
            continue
        c = cars[best[1]]
        c['stops'].add(req['dest'])
        c['load'] += 1
        out.append(best[1])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 9', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [3, 9], 'load': 4, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [8, 6, 12], 'load': 11, 'cap': 13}], 'requests': [{'dest': 10, 'n': 3}, {'dest': 3, 'n': 3}, {'dest': 13, 'n': 1}, {'dest': 2, 'n': 1}, {'dest': 5, 'n': 5}], 'stop_penalty_s': 10, 'per_stop_s': 3}, ['A', 'A', 'A', 'B', None]), ('sampled regression 3', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [8, 13, 9], 'load': 0, 'cap': 13}], 'requests': [{'dest': 13, 'n': 5}, {'dest': 11, 'n': 1}, {'dest': 12, 'n': 5}, {'dest': 3, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'B', 'B', 'B']), ('boundary: group exactly fills the car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 10, 'cap': 12}, {'id': 'B', 'ready_s': 30, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 5, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('boundary: coincident destination beats an idle car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [7], 'load': 0, 'cap': 12}], 'requests': [{'dest': 7, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['B']), ('sampled regression 1', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [10, 11], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [9], 'load': 11, 'cap': 12}, {'id': 'C', 'ready_s': 0, 'stops': [13, 14, 2], 'load': 11, 'cap': 13}], 'requests': [{'dest': 10, 'n': 1}, {'dest': 9, 'n': 5}], 'stop_penalty_s': 10, 'per_stop_s': 3}, ['A', None]), ('control 4', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 11, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [3], 'load': 4, 'cap': 12}, {'id': 'C', 'ready_s': 5, 'stops': [], 'load': 11, 'cap': 13}], 'requests': [{'dest': 7, 'n': 2}, {'dest': 3, 'n': 1}, {'dest': 8, 'n': 1}, {'dest': 3, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['C', 'B', 'A', 'B']), ('control 7', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [11, 6], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [7], 'load': 8, 'cap': 12}, {'id': 'C', 'ready_s': 10, 'stops': [5], 'load': 0, 'cap': 12}], 'requests': [{'dest': 2, 'n': 1}, {'dest': 8, 'n': 5}, {'dest': 11, 'n': 3}, {'dest': 3, 'n': 1}], 'stop_penalty_s': 15, 'per_stop_s': 5}, ['A', 'C', 'A', 'A'])], [('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 38', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 5, 'stops': [2, 13, 9], 'load': 0, 'cap': 13}], 'requests': [{'dest': 13, 'n': 1}, {'dest': 8, 'n': 2}, {'dest': 5, 'n': 3}, {'dest': 13, 'n': 3}, {'dest': 14, 'n': 5}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'A', 'B', 'B', 'B']), ('sampled regression 22', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [7, 5, 11], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'C', 'ready_s': 0, 'stops': [10, 8], 'load': 0, 'cap': 13}], 'requests': [{'dest': 12, 'n': 2}, {'dest': 11, 'n': 5}, {'dest': 13, 'n': 2}, {'dest': 13, 'n': 1}, {'dest': 7, 'n': 5}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['C', 'A', 'A', 'A', 'C']), ('boundary: empty car earns no discount', {'cars': [{'id': 'A', 'ready_s': 4, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [9], 'load': 0, 'cap': 12}], 'requests': [{'dest': 3, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('boundary: equal cost cars', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 5, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 4, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('control 12', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [6, 3], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 4, 'cap': 12}, {'id': 'C', 'ready_s': 20, 'stops': [10, 8], 'load': 11, 'cap': 13}], 'requests': [{'dest': 10, 'n': 1}, {'dest': 2, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'A']), ('control 15', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [3], 'load': 0, 'cap': 13}, {'id': 'B', 'ready_s': 5, 'stops': [7, 2], 'load': 0, 'cap': 13}, {'id': 'C', 'ready_s': 5, 'stops': [12], 'load': 0, 'cap': 12}], 'requests': [{'dest': 2, 'n': 3}, {'dest': 13, 'n': 5}, {'dest': 11, 'n': 1}, {'dest': 2, 'n': 1}, {'dest': 12, 'n': 3}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['B', 'A', 'C', 'B', 'C']), ('control 18', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [2, 7, 5], 'load': 0, 'cap': 12}], 'requests': [{'dest': 10, 'n': 5}, {'dest': 2, 'n': 1}, {'dest': 6, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'A'])], [('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 63', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 4, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [12, 11], 'load': 4, 'cap': 12}], 'requests': [{'dest': 3, 'n': 5}, {'dest': 4, 'n': 5}, {'dest': 11, 'n': 1}, {'dest': 14, 'n': 3}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'B', 'A', 'A']), ('sampled regression 42', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [3, 8, 13], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [6], 'load': 8, 'cap': 13}, {'id': 'C', 'ready_s': 5, 'stops': [12], 'load': 8, 'cap': 13}], 'requests': [{'dest': 10, 'n': 3}, {'dest': 12, 'n': 3}, {'dest': 3, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['C', 'A', 'A']), ('boundary: second group sees the first allocation', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 2, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 6, 'n': 3}, {'dest': 6, 'n': 3}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'A']), ('boundary: no eligible car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 11, 'cap': 12}], 'requests': [{'dest': 5, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, [None]), ('control 23', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [2], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [9, 8], 'load': 4, 'cap': 13}, {'id': 'C', 'ready_s': 10, 'stops': [], 'load': 0, 'cap': 13}], 'requests': [{'dest': 8, 'n': 3}, {'dest': 13, 'n': 1}, {'dest': 9, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['C', 'C', 'B']), ('sampled regression 26', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [9], 'load': 8, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [11, 14, 4], 'load': 8, 'cap': 13}], 'requests': [{'dest': 13, 'n': 1}, {'dest': 5, 'n': 1}, {'dest': 12, 'n': 1}, {'dest': 9, 'n': 1}, {'dest': 7, 'n': 3}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'A', 'A', 'B']), ('control 29', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 13}, {'id': 'B', 'ready_s': 10, 'stops': [2, 5, 7], 'load': 8, 'cap': 13}, {'id': 'C', 'ready_s': 20, 'stops': [2], 'load': 4, 'cap': 12}], 'requests': [{'dest': 6, 'n': 1}, {'dest': 3, 'n': 5}], 'stop_penalty_s': 15, 'per_stop_s': 5}, ['A', 'A'])], [('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 77', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [11, 9, 14], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [6, 3], 'load': 4, 'cap': 12}, {'id': 'C', 'ready_s': 0, 'stops': [5, 13, 12], 'load': 8, 'cap': 13}], 'requests': [{'dest': 5, 'n': 3}, {'dest': 2, 'n': 1}, {'dest': 14, 'n': 3}, {'dest': 5, 'n': 5}, {'dest': 5, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['C', 'C', 'A', 'B', 'C']), ('sampled regression 64', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [11, 7, 3], 'load': 8, 'cap': 13}, {'id': 'C', 'ready_s': 0, 'stops': [8, 3], 'load': 8, 'cap': 13}], 'requests': [{'dest': 6, 'n': 1}, {'dest': 3, 'n': 3}, {'dest': 7, 'n': 3}], 'stop_penalty_s': 8, 'per_stop_s': 5}, ['A', 'C', 'A']), ('boundary: no eligible car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 11, 'cap': 12}], 'requests': [{'dest': 5, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, [None]), ('boundary: group exactly fills the car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 10, 'cap': 12}, {'id': 'B', 'ready_s': 30, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 5, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('control 34', {'cars': [{'id': 'A', 'ready_s': 20, 'stops': [8], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 10, 'stops': [2], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 1}, {'dest': 11, 'n': 3}, {'dest': 5, 'n': 1}, {'dest': 9, 'n': 1}, {'dest': 10, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['B', 'B', 'A', 'B', 'A']), ('control 37', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 8, 'cap': 12}, {'id': 'B', 'ready_s': 5, 'stops': [9, 14, 8], 'load': 8, 'cap': 12}], 'requests': [{'dest': 5, 'n': 1}, {'dest': 8, 'n': 1}, {'dest': 2, 'n': 2}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'B', 'A']), ('sampled regression 40', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 4, 'cap': 13}, {'id': 'B', 'ready_s': 0, 'stops': [10, 5, 7], 'load': 0, 'cap': 12}], 'requests': [{'dest': 5, 'n': 5}, {'dest': 5, 'n': 5}, {'dest': 7, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 5}, ['A', 'B', 'A'])], [('regression: capacity used up by earlier groups', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 6, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 3}, {'dest': 8, 'n': 3}, {'dest': 9, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A', 'A', 'B']), ('sampled regression 19', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 5, 'stops': [14, 11], 'load': 0, 'cap': 12}], 'requests': [{'dest': 13, 'n': 5}, {'dest': 7, 'n': 1}], 'stop_penalty_s': 15, 'per_stop_s': 5}, ['A', 'B']), ('sampled regression 3', {'cars': [{'id': 'A', 'ready_s': 10, 'stops': [], 'load': 8, 'cap': 13}, {'id': 'B', 'ready_s': 20, 'stops': [8, 13, 9], 'load': 0, 'cap': 13}], 'requests': [{'dest': 13, 'n': 5}, {'dest': 11, 'n': 1}, {'dest': 12, 'n': 5}, {'dest': 3, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['A', 'B', 'B', 'B']), ('boundary: coincident destination beats an idle car', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [7], 'load': 0, 'cap': 12}], 'requests': [{'dest': 7, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['B']), ('boundary: empty car earns no discount', {'cars': [{'id': 'A', 'ready_s': 4, 'stops': [], 'load': 0, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [9], 'load': 0, 'cap': 12}], 'requests': [{'dest': 3, 'n': 1}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['A']), ('control 45', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [5], 'load': 4, 'cap': 12}, {'id': 'B', 'ready_s': 0, 'stops': [], 'load': 0, 'cap': 12}], 'requests': [{'dest': 6, 'n': 5}, {'dest': 9, 'n': 5}, {'dest': 13, 'n': 1}, {'dest': 9, 'n': 2}, {'dest': 8, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 3}, ['B', 'A', 'B', 'A', 'A']), ('control 48', {'cars': [{'id': 'A', 'ready_s': 0, 'stops': [7], 'load': 11, 'cap': 12}, {'id': 'B', 'ready_s': 20, 'stops': [2, 13], 'load': 11, 'cap': 13}, {'id': 'C', 'ready_s': 20, 'stops': [10, 12], 'load': 11, 'cap': 12}], 'requests': [{'dest': 6, 'n': 2}, {'dest': 14, 'n': 5}], 'stop_penalty_s': 10, 'per_stop_s': 5}, ['B', None]), ('control 51', {'cars': [{'id': 'A', 'ready_s': 5, 'stops': [3], 'load': 8, 'cap': 12}, {'id': 'B', 'ready_s': 10, 'stops': [12, 8], 'load': 0, 'cap': 12}, {'id': 'C', 'ready_s': 20, 'stops': [10], 'load': 0, 'cap': 13}], 'requests': [{'dest': 14, 'n': 1}, {'dest': 13, 'n': 2}, {'dest': 5, 'n': 1}], 'stop_penalty_s': 8, 'per_stop_s': 5}, ['A', 'A', 'A'])]]
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: capacity used up by earlier groups	`['A', 'A', 'A']`	`['A', 'A', 'B']`	Failed
sampled regression 9	`['A', 'A', 'A', 'B', 'A']`	`['A', 'A', 'A', 'B', None]`	Failed
sampled regression 3	`['A', 'A', 'B', 'A']`	`['A', 'B', 'B', 'B']`	Failed
boundary: group exactly fills the car	`['A']`	`['A']`	Passed
boundary: coincident destination beats an idle car	`['B']`	`['B']`	Passed
sampled regression 1	`['A', None]`	`['A', None]`	Passed
control 4	`['C', 'B', 'A', 'B']`	`['C', 'B', 'A', 'B']`	Passed
control 7	`['A', 'C', 'A', 'A']`	`['A', 'C', 'A', 'A']`	Passed

SHA-256 / c3e500cdf20821842bbcad560914a3959019e411831fc1c81fcf7f91ece72dea

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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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 2026-09-29T14:47:52.387586+00:00.

Case digest / 048fb23a19077be298fd0a6a19ca8dbbb8f14725df10766652b002160d0f5677