{"abstract":"The sum of parallel bases is not averaged.","category":"Planar geometry","checks":4,"contract":"Integer coordinates and lengths, with exact arithmetic except for indicated division results. Lengths are nonnegative. Rectangles are (xmin,ymin,xmax,ymax) with ordered bounds; coordinate vectors have matching dimensions. Trapezoid area. Exact operational definition: (a+b)*h/2","evaluation_group":"model-a11c154d35b3e24f","failed_approach":"The bases multiply instead of adding.","family":"xn-trapezoid-area","id":"FA-5811","implementations":{"attempt":{"sha256":"67fdcd6705ddfc1d281245bead16d8ea3975d73ff243171d012608956b3392be","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(a, b, h):\n    return a*b*h/2\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (3, 5, 2)', solve(*(3, 5, 2)), 8)\ncheck('fixture 2: (2, 2, 3)', solve(*(2, 2, 3)), 6)\ncheck('fixture 3: (0, 4, 2)', solve(*(0, 4, 2)), 4)\ncheck('fixture 4: (3, 5, 0)', solve(*(3, 5, 0)), 0)\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":"9156765183358409ce4e4d885e90ff7ac1e9f219e3baf4c7ff4d6262b64b022f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(a, b, h):\n    return (a+b)*h\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (3, 5, 2)', solve(*(3, 5, 2)), 8)\ncheck('fixture 2: (2, 2, 3)', solve(*(2, 2, 3)), 6)\ncheck('fixture 3: (0, 4, 2)', solve(*(0, 4, 2)), 4)\ncheck('fixture 4: (3, 5, 0)', solve(*(3, 5, 0)), 0)\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"},"fixed":{"sha256":"dda14603033fc01bdf11d53c234aec10e80601feab1342a3353461f2ded52014","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(a, b, h):\n    return (a+b)*h/2\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (3, 5, 2)', solve(*(3, 5, 2)), 8)\ncheck('fixture 2: (2, 2, 3)', solve(*(2, 2, 3)), 6)\ncheck('fixture 3: (0, 4, 2)', solve(*(0, 4, 2)), 4)\ncheck('fixture 4: (3, 5, 0)', solve(*(3, 5, 0)), 0)\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":" 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":"xn-trapezoid-area","generated_at":"2026-09-29T14:37:54.002703+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Small exact fixtures expose this error without platform timing, external services, or probabilistic observations. Planar geometry results depend on the stated convention.","repair":"Apply the specified mathematical contract directly, preserving all terms and boundary cases: return (a+b)*h/2","root_cause":"The sum of parallel bases is not averaged.","sha256":"aa597fcd03c85b5369e145e5664e33837745799737a6ec083c8a5d861878b63f","title":"Trapezoid area · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":116.312,"exit_code":1,"observations":[{"actual":15.0,"check":"fixture 1: (3, 5, 2)","expected":8,"passed":false},{"actual":6.0,"check":"fixture 2: (2, 2, 3)","expected":6,"passed":true},{"actual":0.0,"check":"fixture 3: (0, 4, 2)","expected":4,"passed":false},{"actual":0.0,"check":"fixture 4: (3, 5, 0)","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (3, 5, 2)\", \"actual\": 15.0, \"expected\": 8, \"passed\": false}, {\"check\": \"fixture 2: (2, 2, 3)\", \"actual\": 6.0, \"expected\": 6, \"passed\": true}, {\"check\": \"fixture 3: (0, 4, 2)\", \"actual\": 0.0, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 4: (3, 5, 0)\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":49.332,"exit_code":1,"observations":[{"actual":16,"check":"fixture 1: (3, 5, 2)","expected":8,"passed":false},{"actual":12,"check":"fixture 2: (2, 2, 3)","expected":6,"passed":false},{"actual":8,"check":"fixture 3: (0, 4, 2)","expected":4,"passed":false},{"actual":0,"check":"fixture 4: (3, 5, 0)","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (3, 5, 2)\", \"actual\": 16, \"expected\": 8, \"passed\": false}, {\"check\": \"fixture 2: (2, 2, 3)\", \"actual\": 12, \"expected\": 6, \"passed\": false}, {\"check\": \"fixture 3: (0, 4, 2)\", \"actual\": 8, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 4: (3, 5, 0)\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":51.345,"exit_code":0,"observations":[{"actual":8.0,"check":"fixture 1: (3, 5, 2)","expected":8,"passed":true},{"actual":6.0,"check":"fixture 2: (2, 2, 3)","expected":6,"passed":true},{"actual":4.0,"check":"fixture 3: (0, 4, 2)","expected":4,"passed":true},{"actual":0.0,"check":"fixture 4: (3, 5, 0)","expected":0,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (3, 5, 2)\", \"actual\": 8.0, \"expected\": 8, \"passed\": true}, {\"check\": \"fixture 2: (2, 2, 3)\", \"actual\": 6.0, \"expected\": 6, \"passed\": true}, {\"check\": \"fixture 3: (0, 4, 2)\", \"actual\": 4.0, \"expected\": 4, \"passed\": true}, {\"check\": \"fixture 4: (3, 5, 0)\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}