{"abstract":"Dividing by 256 makes the maximum representable white less than one.","category":"Color encoding","checks":4,"contract":"Map integer byte values in [0,255] to normalized [0,1] with both endpoints exact.","contract_signature":"byte","evaluation_group":"xg-byte-channel-normalization","failed_approach":"Integer division reduces nearly all nonwhite channels to black.","family":"xg-byte-channel-normalization","id":"FA-10611","implementations":{"attempt":{"sha256":"591e377c0a1dafec26e763aa211ad69f535db974c7f7a0edb4b4d437f8aed3d4","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(byte):\n    return byte//255\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(255,)), 1)\ncheck('fixture 2', solve(*(0,)), 0)\ncheck('fixture 3', solve(*(85,)), 0.3333333333333333)\ncheck('fixture 4', solve(*(128,)), 0.5019607843137255)\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":"b17b00cebb088a4e4138bfeab1b27bfb43c52eff055c2951b82a268740a5d38d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(byte):\n    return byte/256\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(255,)), 1)\ncheck('fixture 2', solve(*(0,)), 0)\ncheck('fixture 3', solve(*(85,)), 0.3333333333333333)\ncheck('fixture 4', solve(*(128,)), 0.5019607843137255)\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":"xg-byte-channel-normalization","generated_at":"2026-09-29T14:38:40.582287+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic software graphics stage with explicit channel and coordinate conventions; no hardware, device profile or API behavior is inferred.","root_cause":"Dividing by 256 makes the maximum representable white less than one.","sha256":"8160cafaa874e3d12984f136d3345530f99e5429a82abccfacd1eea4f78a7c81","title":"Byte channel normalization · 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":40.051,"exit_code":1,"observations":[{"actual":1,"check":"fixture 1","expected":1,"passed":true},{"actual":0,"check":"fixture 2","expected":0,"passed":true},{"actual":0,"check":"fixture 3","expected":0.3333333333333333,"passed":false},{"actual":0,"check":"fixture 4","expected":0.5019607843137255,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0.3333333333333333, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": 0, \"expected\": 0.5019607843137255, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.4,"exit_code":1,"observations":[{"actual":0.99609375,"check":"fixture 1","expected":1,"passed":false},{"actual":0.0,"check":"fixture 2","expected":0,"passed":true},{"actual":0.33203125,"check":"fixture 3","expected":0.3333333333333333,"passed":false},{"actual":0.5,"check":"fixture 4","expected":0.5019607843137255,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 0.99609375, \"expected\": 1, \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0.33203125, \"expected\": 0.3333333333333333, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": 0.5, \"expected\": 0.5019607843137255, \"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."}}