{"abstract":"Dividing by sample count never reaches the requested final gain.","category":"Audio channel mixing","checks":4,"contract":"Apply a linear gain ramp including start on the first and end on the last of two or more samples; a singleton uses end gain.","evaluation_group":"xaud-gain-ramp-reaches-final-frame","failed_approach":"A constant starting gain ignores the ramp entirely.","family":"xaud-gain-ramp-reaches-final-frame","id":"FA-10906","implementations":{"attempt":{"sha256":"7bbee627e11a5433edc66fc69e3ad7054c2637c27395d970906ae1bec36aaa2f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(samples, start, end):\n    return [x*start for x in samples]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1, 1, 1], 0, 1)),[0, 0.5, 1])\ncheck('fixture 2',solve(*([2], 0, 1)),[2])\ncheck('fixture 3',solve(*([], 0, 1)),[])\ncheck('fixture 4',solve(*([1, 1], 1, 0)),[1, 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":"bfc0056050a77033ad07d723644eaa4c90efcc42fd8f15448fa8d091dd9e5866","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(samples, start, end):\n    return [x*(start+(end-start)*i/len(samples)) for i,x in enumerate(samples)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1, 1, 1], 0, 1)),[0, 0.5, 1])\ncheck('fixture 2',solve(*([2], 0, 1)),[2])\ncheck('fixture 3',solve(*([], 0, 1)),[])\ncheck('fixture 4',solve(*([1, 1], 1, 0)),[1, 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":"b967e945d750c9024300d82419bd5cedad916c3549109cf68391dc4fd7f911e3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(samples, start, end):\n    return [x*(start+(end-start)*i/(len(samples)-1)) for i,x in enumerate(samples)] if len(samples)>1 else ([samples[0]*end] if samples else [])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([1, 1, 1], 0, 1)),[0, 0.5, 1])\ncheck('fixture 2',solve(*([2], 0, 1)),[2])\ncheck('fixture 3',solve(*([], 0, 1)),[])\ncheck('fixture 4',solve(*([1, 1], 1, 0)),[1, 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":"xaud-gain-ramp-reaches-final-frame","generated_at":"2026-09-29T14:38:43.231432+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A pure Python local audio pipeline stage with explicit sample formats and frame conventions; no real-time device or signal-spectrum claims.","repair":"Apply the explicit PCM/playback contract: Apply a linear gain ramp including start on the first and end on the last of two or more samples; a singleton uses end gain.","root_cause":"Dividing by sample count never reaches the requested final gain.","sha256":"168c7b642532074fbc5bd5a6930af1ff3ab7dbd11dd867a757b4ed3c77512550","title":"Gain ramp reaches final frame · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":39.621,"exit_code":1,"observations":[{"actual":[0,0,0],"check":"fixture 1","expected":[0,0.5,1],"passed":false},{"actual":[0],"check":"fixture 2","expected":[2],"passed":false},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[1,1],"check":"fixture 4","expected":[1,0],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [0, 0, 0], \"expected\": [0, 0.5, 1], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [0], \"expected\": [2], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [1, 1], \"expected\": [1, 0], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.561,"exit_code":1,"observations":[{"actual":[0.0,0.3333333333333333,0.6666666666666666],"check":"fixture 1","expected":[0,0.5,1],"passed":false},{"actual":[0.0],"check":"fixture 2","expected":[2],"passed":false},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[1.0,0.5],"check":"fixture 4","expected":[1,0],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [0.0, 0.3333333333333333, 0.6666666666666666], \"expected\": [0, 0.5, 1], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [0.0], \"expected\": [2], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [1.0, 0.5], \"expected\": [1, 0], \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":40.496,"exit_code":0,"observations":[{"actual":[0.0,0.5,1.0],"check":"fixture 1","expected":[0,0.5,1],"passed":true},{"actual":[2],"check":"fixture 2","expected":[2],"passed":true},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[1.0,0.0],"check":"fixture 4","expected":[1,0],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [0.0, 0.5, 1.0], \"expected\": [0, 0.5, 1], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [2], \"expected\": [2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [1.0, 0.0], \"expected\": [1, 0], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}