{"abstract":"Truncating scaled color introduces a downward quantization bias.","category":"Color encoding","checks":5,"contract":"Clamp a finite normalized channel to byte range and round the scaled value to nearest with half-up ties.","contract_signature":"value","evaluation_group":"xg-normalized-channel-to-byte-half-up","failed_approach":"Banker rounding changes even-integer midpoint ties from half-up behavior.","family":"xg-normalized-channel-to-byte-half-up","id":"FA-10606","implementations":{"attempt":{"sha256":"7294d8570de62ff4b1be61f00236d047340e3202ad4f535b39eac5f1c498761e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(value):\n    return min(255,max(0,round(value*255)))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(0.5,)), 128)\ncheck('fixture 2', solve(*(0.3,)), 77)\ncheck('fixture 3', solve(*(-0.5,)), 0)\ncheck('fixture 4', solve(*(1.5,)), 255)\ncheck('fixture 5', solve(*(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":"d25b1c15899371953e3351874644468bf1d7beb93b0772834575404d59dce1b0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(value):\n    return int(value*255)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(0.5,)), 128)\ncheck('fixture 2', solve(*(0.3,)), 77)\ncheck('fixture 3', solve(*(-0.5,)), 0)\ncheck('fixture 4', solve(*(1.5,)), 255)\ncheck('fixture 5', solve(*(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":"xg-normalized-channel-to-byte-half-up","generated_at":"2026-09-29T14:38:40.547767+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":"Truncating scaled color introduces a downward quantization bias.","sha256":"c4e72d74f3c3d84d6fd13e57ffa2ca931067ec14f6497db710c6cbde5b960e5d","title":"Normalized channel to byte half up · 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":40.669,"exit_code":1,"observations":[{"actual":128,"check":"fixture 1","expected":128,"passed":true},{"actual":76,"check":"fixture 2","expected":77,"passed":false},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":255,"check":"fixture 4","expected":255,"passed":true},{"actual":0,"check":"fixture 5","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 128, \"expected\": 128, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": 76, \"expected\": 77, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 255, \"expected\": 255, \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.631,"exit_code":1,"observations":[{"actual":127,"check":"fixture 1","expected":128,"passed":false},{"actual":76,"check":"fixture 2","expected":77,"passed":false},{"actual":-127,"check":"fixture 3","expected":0,"passed":false},{"actual":382,"check":"fixture 4","expected":255,"passed":false},{"actual":0,"check":"fixture 5","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": 127, \"expected\": 128, \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": 76, \"expected\": 77, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": -127, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": 382, \"expected\": 255, \"passed\": false}, {\"check\": \"fixture 5\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"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."}}