{"abstract":"Coverage samples pixel corners instead of pixel centers.","category":"Raster clipping","checks":4,"contract":"List integer pixel indices whose centers i+0.5 are covered by finite half-open span [left,right); width is a nonnegative integer.","evaluation_group":"xg-pixel-center-coverage","failed_approach":"Strict lower coverage drops a center lying exactly on the included left edge.","family":"xg-pixel-center-coverage","id":"FA-10661","implementations":{"attempt":{"sha256":"84bac0b162a969c236f7ccb04aaee8414ddff2a855a14b2893d8dcbace360af0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(width, left, right):\n    return [i for i in range(width) if left<i+.5<right]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(4, 0.5, 2.5)), [0, 1])\ncheck('fixture 2', solve(*(4, 0.6, 2.6)), [1, 2])\ncheck('fixture 3', solve(*(3, 0, 3)), [0, 1, 2])\ncheck('fixture 4', solve(*(3, 1, 1)), [])\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":"01f5612e398c9e68740a771f0b8f90abcd4617cc269dd1892cb7e8334951c9ae","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(width, left, right):\n    return [i for i in range(width) if left<=i<right]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(4, 0.5, 2.5)), [0, 1])\ncheck('fixture 2', solve(*(4, 0.6, 2.6)), [1, 2])\ncheck('fixture 3', solve(*(3, 0, 3)), [0, 1, 2])\ncheck('fixture 4', solve(*(3, 1, 1)), [])\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":"5b65d6a8fe00c3accbdb3049d8b00b02904e341e3ff0e47d0c0d8381cbe9364a","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(width, left, right):\n    return [i for i in range(width) if left<=i+.5<right]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*(4, 0.5, 2.5)), [0, 1])\ncheck('fixture 2', solve(*(4, 0.6, 2.6)), [1, 2])\ncheck('fixture 3', solve(*(3, 0, 3)), [0, 1, 2])\ncheck('fixture 4', solve(*(3, 1, 1)), [])\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-pixel-center-coverage","generated_at":"2026-09-29T14:38:41.088957+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.","repair":"Use the stage contract: List integer pixel indices whose centers i+0.5 are covered by finite half-open span [left,right); width is a nonnegative integer.","root_cause":"Coverage samples pixel corners instead of pixel centers.","sha256":"51b526d4e7c02ecbe5f2ad0f25ea5627e17790ccf8e4ccf6a1acda2d57159090","title":"Pixel center coverage · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":44.725,"exit_code":1,"observations":[{"actual":[1],"check":"fixture 1","expected":[0,1],"passed":false},{"actual":[1,2],"check":"fixture 2","expected":[1,2],"passed":true},{"actual":[0,1,2],"check":"fixture 3","expected":[0,1,2],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [1], \"expected\": [0, 1], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [0, 1, 2], \"expected\": [0, 1, 2], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.788,"exit_code":1,"observations":[{"actual":[1,2],"check":"fixture 1","expected":[0,1],"passed":false},{"actual":[1,2],"check":"fixture 2","expected":[1,2],"passed":true},{"actual":[0,1,2],"check":"fixture 3","expected":[0,1,2],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [1, 2], \"expected\": [0, 1], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [0, 1, 2], \"expected\": [0, 1, 2], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":39.971,"exit_code":0,"observations":[{"actual":[0,1],"check":"fixture 1","expected":[0,1],"passed":true},{"actual":[1,2],"check":"fixture 2","expected":[1,2],"passed":true},{"actual":[0,1,2],"check":"fixture 3","expected":[0,1,2],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [0, 1], \"expected\": [0, 1], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [0, 1, 2], \"expected\": [0, 1, 2], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}