{"abstract":"Every sample receives a full interval weight, including both endpoints.","category":"Discrete calculus","checks":4,"contract":"Integer sample values and compatible sample-array lengths. Rational results are reduced Fraction strings; spacing is positive unless explicitly stated otherwise. Trapezoidal integral unit grid. Exact operational definition: str(sum((Fraction(a+b,2) for a,b in zip(values,values[1:])),Fraction()))","evaluation_group":"model-c715b453939e3eb8","failed_approach":"A left rectangle rule omits the right endpoint averaging.","family":"xn-trapezoidal-integral-unit-grid","id":"FA-6371","implementations":{"attempt":{"sha256":"47c154aa6e47c1be94b3281a1ddc6dc07d31d1a317320c32776b15db51bbb758","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(values):\n    return str(sum(values[:-1]))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: ([0, 1, 2],)', solve(*([0, 1, 2],)), '2')\ncheck('fixture 2: ([3, 3],)', solve(*([3, 3],)), '3')\ncheck('fixture 3: ([5],)', solve(*([5],)), '0')\ncheck('fixture 4: ([],)', solve(*([],)), '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":"8560df9d02b7a4d7ece173756f151e84ac1665638e5a38fc9caf1fb397f0b9f1","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(values):\n    return str(sum(values))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: ([0, 1, 2],)', solve(*([0, 1, 2],)), '2')\ncheck('fixture 2: ([3, 3],)', solve(*([3, 3],)), '3')\ncheck('fixture 3: ([5],)', solve(*([5],)), '0')\ncheck('fixture 4: ([],)', solve(*([],)), '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":"27ade3b852026b62779e8da7f59ef0f4f2442d4eb857ab9d7f56ff31bbaf1563","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(values):\n    return str(sum((Fraction(a+b,2) for a,b in zip(values,values[1:])),Fraction()))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: ([0, 1, 2],)', solve(*([0, 1, 2],)), '2')\ncheck('fixture 2: ([3, 3],)', solve(*([3, 3],)), '3')\ncheck('fixture 3: ([5],)', solve(*([5],)), '0')\ncheck('fixture 4: ([],)', solve(*([],)), '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-trapezoidal-integral-unit-grid","generated_at":"2026-09-29T14:38:01.002172+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. Discrete calculus results depend on the stated convention.","repair":"Apply the specified mathematical contract directly, preserving all terms and boundary cases: return str(sum((Fraction(a+b,2) for a,b in zip(values,values[1:])),Fraction()))","root_cause":"Every sample receives a full interval weight, including both endpoints.","sha256":"99e9d350fd836ad33507f597424f69a4c84af0c7c0d82696c20a2e5dcf2a0701","title":"Trapezoidal integral unit grid · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":47.552,"exit_code":1,"observations":[{"actual":"1","check":"fixture 1: ([0, 1, 2],)","expected":"2","passed":false},{"actual":"3","check":"fixture 2: ([3, 3],)","expected":"3","passed":true},{"actual":"0","check":"fixture 3: ([5],)","expected":"0","passed":true},{"actual":"0","check":"fixture 4: ([],)","expected":"0","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: ([0, 1, 2],)\", \"actual\": \"1\", \"expected\": \"2\", \"passed\": false}, {\"check\": \"fixture 2: ([3, 3],)\", \"actual\": \"3\", \"expected\": \"3\", \"passed\": true}, {\"check\": \"fixture 3: ([5],)\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"fixture 4: ([],)\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":49.271,"exit_code":1,"observations":[{"actual":"3","check":"fixture 1: ([0, 1, 2],)","expected":"2","passed":false},{"actual":"6","check":"fixture 2: ([3, 3],)","expected":"3","passed":false},{"actual":"5","check":"fixture 3: ([5],)","expected":"0","passed":false},{"actual":"0","check":"fixture 4: ([],)","expected":"0","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: ([0, 1, 2],)\", \"actual\": \"3\", \"expected\": \"2\", \"passed\": false}, {\"check\": \"fixture 2: ([3, 3],)\", \"actual\": \"6\", \"expected\": \"3\", \"passed\": false}, {\"check\": \"fixture 3: ([5],)\", \"actual\": \"5\", \"expected\": \"0\", \"passed\": false}, {\"check\": \"fixture 4: ([],)\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":156.743,"exit_code":0,"observations":[{"actual":"2","check":"fixture 1: ([0, 1, 2],)","expected":"2","passed":true},{"actual":"3","check":"fixture 2: ([3, 3],)","expected":"3","passed":true},{"actual":"0","check":"fixture 3: ([5],)","expected":"0","passed":true},{"actual":"0","check":"fixture 4: ([],)","expected":"0","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: ([0, 1, 2],)\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}, {\"check\": \"fixture 2: ([3, 3],)\", \"actual\": \"3\", \"expected\": \"3\", \"passed\": true}, {\"check\": \"fixture 3: ([5],)\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"fixture 4: ([],)\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}