{"abstract":"The reduction disagrees with its explicit aggregation oracle.","category":"Numerical aggregation","checks":6,"contract":"Return sum(abs(x-anchor)); empty input returns zero. Anchor is supplied, not estimated.","contract_signature":"xs, anchor","evaluation_group":"s3-na-absolute-deviation-about-anchor","failed_approach":"Taking absolute observations before subtracting the anchor breaks negative anchors.","family":"s3-numerical-aggregation-absolute-deviation-about-anchor-absolute-after-sum","id":"FA-12866","implementations":{"attempt":{"sha256":"15629fef653b444cc2cc5aac4358cc429890f923635a0d87ed9ba71127da4748","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nfrom collections import Counter, defaultdict\nimport math\nimport itertools\nN = 1\nobservations = []\ndef solve(xs, anchor):\n    return sum(abs(abs(x)-anchor) for x in xs)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('regression 1', solve(*([1, 5, 9], 5)), 8)\ncheck('regression 2', solve(*([], 4)), 0)\ncheck('regression 3', solve(*([4, 4], 4)), 0)\ncheck('regression 4', solve(*([-3, -1], 2)), 8)\ncheck('regression 5', solve(*([0, 0, 6], 1)), 7)\ncheck(\"variable anchor\", solve([N-3,N+2,N+2],N),7)\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":"c0d908562c866bfe197936d6f8783362164e6ab8ee682f957b23c7bf2426f10c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nfrom collections import Counter, defaultdict\nimport math\nimport itertools\nN = 1\nobservations = []\ndef solve(xs, anchor):\n    return abs(sum(x-anchor for x in xs))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('regression 1', solve(*([1, 5, 9], 5)), 8)\ncheck('regression 2', solve(*([], 4)), 0)\ncheck('regression 3', solve(*([4, 4], 4)), 0)\ncheck('regression 4', solve(*([-3, -1], 2)), 8)\ncheck('regression 5', solve(*([0, 0, 6], 1)), 7)\ncheck(\"variable anchor\", solve([N-3,N+2,N+2],N),7)\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":"Small offline integer/rational inputs only; no performance, statistical inference, or production-library conformance claim. 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":"s3-numerical-aggregation-absolute-deviation-about-anchor-absolute-after-sum","generated_at":"2026-09-29T14:39:01.250375+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Exact bounded examples isolate a reduction defect without floating-point or external-service effects.","root_cause":"Absolute value is applied after cancellation of signed deviations.","sha256":"438d1af3abdf299a5b8a0b044f43b8193b5a5b1794cbb9cd5b6d8c7eff714664","title":"Absolute deviation about anchor: Absolute value is applied after cancellation of signed deviations. · 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":49.986,"exit_code":1,"observations":[{"actual":8,"check":"regression 1","expected":8,"passed":true},{"actual":0,"check":"regression 2","expected":0,"passed":true},{"actual":0,"check":"regression 3","expected":0,"passed":true},{"actual":2,"check":"regression 4","expected":8,"passed":false},{"actual":7,"check":"regression 5","expected":7,"passed":true},{"actual":5,"check":"variable anchor","expected":7,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression 1\", \"actual\": 8, \"expected\": 8, \"passed\": true}, {\"check\": \"regression 2\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"regression 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"regression 4\", \"actual\": 2, \"expected\": 8, \"passed\": false}, {\"check\": \"regression 5\", \"actual\": 7, \"expected\": 7, \"passed\": true}, {\"check\": \"variable anchor\", \"actual\": 5, \"expected\": 7, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":48.668,"exit_code":1,"observations":[{"actual":0,"check":"regression 1","expected":8,"passed":false},{"actual":0,"check":"regression 2","expected":0,"passed":true},{"actual":0,"check":"regression 3","expected":0,"passed":true},{"actual":8,"check":"regression 4","expected":8,"passed":true},{"actual":3,"check":"regression 5","expected":7,"passed":false},{"actual":1,"check":"variable anchor","expected":7,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression 1\", \"actual\": 0, \"expected\": 8, \"passed\": false}, {\"check\": \"regression 2\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"regression 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"regression 4\", \"actual\": 8, \"expected\": 8, \"passed\": true}, {\"check\": \"regression 5\", \"actual\": 3, \"expected\": 7, \"passed\": false}, {\"check\": \"variable anchor\", \"actual\": 1, \"expected\": 7, \"passed\": false}], \"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."}}