{"abstract":"The interval origin is not removed.","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. a,b,x are integers; return None when the endpoint interval has zero span. Exact operational definition: str(Fraction(x-a,b-a)) if a!=b else None","contract_signature":"a, b, x","evaluation_group":"model-dc93d86cc6a34ad1","failed_approach":"Reversing the span sign reverses the parameter direction.","family":"xn-inverse-linear-interpolation","id":"FA-6401","implementations":{"attempt":{"sha256":"2a99541309c849e5b7ef708d5a53b153c296eafc2316923175b5ebf67697b949","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, x):\n    return str(Fraction(x-a,a-b)) if a!=b else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (2, 10, 4)', solve(*(2, 10, 4)), '1/4')\ncheck('fixture 2: (3, 7, 3)', solve(*(3, 7, 3)), '0')\ncheck('fixture 3: (3, 7, 7)', solve(*(3, 7, 7)), '1')\ncheck('fixture 4: (2, 2, 2)', solve(*(2, 2, 2)), None)\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":"c3af5676b751693b1cc1dca09a59cf0afd357ef6c5d592432c8af383fd2efba1","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, x):\n    return str(Fraction(x,b)) if b else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (2, 10, 4)', solve(*(2, 10, 4)), '1/4')\ncheck('fixture 2: (3, 7, 3)', solve(*(3, 7, 3)), '0')\ncheck('fixture 3: (3, 7, 7)', solve(*(3, 7, 7)), '1')\ncheck('fixture 4: (2, 2, 2)', solve(*(2, 2, 2)), None)\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-inverse-linear-interpolation","generated_at":"2026-09-29T14:38:01.538736+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.","root_cause":"The interval origin is not removed.","sha256":"fa39f8e5a597d4ee7ef9a6499599a0739e74ac28b5a197c604246a2a4c5117d7","title":"Inverse linear interpolation · 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":64.682,"exit_code":1,"observations":[{"actual":"-1/4","check":"fixture 1: (2, 10, 4)","expected":"1/4","passed":false},{"actual":"0","check":"fixture 2: (3, 7, 3)","expected":"0","passed":true},{"actual":"-1","check":"fixture 3: (3, 7, 7)","expected":"1","passed":false},{"actual":null,"check":"fixture 4: (2, 2, 2)","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (2, 10, 4)\", \"actual\": \"-1/4\", \"expected\": \"1/4\", \"passed\": false}, {\"check\": \"fixture 2: (3, 7, 3)\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"fixture 3: (3, 7, 7)\", \"actual\": \"-1\", \"expected\": \"1\", \"passed\": false}, {\"check\": \"fixture 4: (2, 2, 2)\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":76.447,"exit_code":1,"observations":[{"actual":"2/5","check":"fixture 1: (2, 10, 4)","expected":"1/4","passed":false},{"actual":"3/7","check":"fixture 2: (3, 7, 3)","expected":"0","passed":false},{"actual":"1","check":"fixture 3: (3, 7, 7)","expected":"1","passed":true},{"actual":"1","check":"fixture 4: (2, 2, 2)","expected":null,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (2, 10, 4)\", \"actual\": \"2/5\", \"expected\": \"1/4\", \"passed\": false}, {\"check\": \"fixture 2: (3, 7, 3)\", \"actual\": \"3/7\", \"expected\": \"0\", \"passed\": false}, {\"check\": \"fixture 3: (3, 7, 7)\", \"actual\": \"1\", \"expected\": \"1\", \"passed\": true}, {\"check\": \"fixture 4: (2, 2, 2)\", \"actual\": \"1\", \"expected\": null, \"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."}}