{"abstract":"Fixed-width chunks use floor instead of ceiling count.","category":"Sequence batch packing","checks":6,"contract":"Split tokens into consecutive chunks of at most positive width; preserve a final partial chunk.","contract_signature":"tokens, width","evaluation_group":"xaud-audio-block-partition-keeps-final-tail","failed_approach":"Ceiling the range and then adding one creates an empty trailing chunk on exact multiples.","family":"w3-sequence-batch-packing-fixed-width-window-count","id":"FA-98071","implementations":{"attempt":{"sha256":"a60e67532eb064a48156237dec263c9e880875edb3b2bce8b23045d3fa3484ac","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(tokens, width):\n    return [tokens[i:i+width] for i in range(0,((len(tokens)+width-1)//width+1)*width,width)] if tokens else []\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ndata=list(range(N+1))\ncheck('partial tail', solve(data,N), [data[:N],data[N:]])\ncheck('exact multiple', solve(list(range(2*N)),N), [list(range(N)),list(range(N,2*N))])\ncheck('short singleton', solve([N],N+1), [[N]])\ncheck('empty', solve([],N), [])\ncheck('unit chunks', solve([1,2,3],1), [[1],[2],[3]])\ncheck('single width', solve([4],4), [[4]])\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":"34cc1dfbc8815f7057477a3f45d58ab08783027db506063f39ef719831ebbdec","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(tokens, width):\n    return [tokens[i:i+width] for i in range(0,(len(tokens)//width)*width,width)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ndata=list(range(N+1))\ncheck('partial tail', solve(data,N), [data[:N],data[N:]])\ncheck('exact multiple', solve(list(range(2*N)),N), [list(range(N)),list(range(N,2*N))])\ncheck('short singleton', solve([N],N+1), [[N]])\ncheck('empty', solve([],N), [])\ncheck('unit chunks', solve([1,2,3],1), [[1],[2],[3]])\ncheck('single width', solve([4],4), [[4]])\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":"Inputs are short integer-token lists under the stated toy contract; results do not claim compatibility with a specific training framework. 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":"w3-sequence-batch-packing-fixed-width-window-count","generated_at":"2026-09-30T16:48:08.895812+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic toy packing rule models a common boundary in preparing bounded training sequences.","root_cause":"The final range endpoint is rounded down to a whole number of chunks.","sha256":"ac27fa895c7d1194ec4189e74cb87edb7681b70cf7acbdc2ae3eea8609169af9","title":"Fixed-width chunks use floor instead of ceiling count · case 01","variant":1,"variant_policy":"The fixture code references N, supplied as 1 through 5. Fixed boundary checks may repeat. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":30.018,"exit_code":1,"observations":[{"actual":[[0],[1],[]],"check":"partial tail","expected":[[0],[1]],"passed":false},{"actual":[[0],[1],[]],"check":"exact multiple","expected":[[0],[1]],"passed":false},{"actual":[[1],[]],"check":"short singleton","expected":[[1]],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[1],[2],[3],[]],"check":"unit chunks","expected":[[1],[2],[3]],"passed":false},{"actual":[[4],[]],"check":"single width","expected":[[4]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"partial tail\", \"actual\": [[0], [1], []], \"expected\": [[0], [1]], \"passed\": false}, {\"check\": \"exact multiple\", \"actual\": [[0], [1], []], \"expected\": [[0], [1]], \"passed\": false}, {\"check\": \"short singleton\", \"actual\": [[1], []], \"expected\": [[1]], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"unit chunks\", \"actual\": [[1], [2], [3], []], \"expected\": [[1], [2], [3]], \"passed\": false}, {\"check\": \"single width\", \"actual\": [[4], []], \"expected\": [[4]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":28.081,"exit_code":1,"observations":[{"actual":[[0],[1]],"check":"partial tail","expected":[[0],[1]],"passed":true},{"actual":[[0],[1]],"check":"exact multiple","expected":[[0],[1]],"passed":true},{"actual":[],"check":"short singleton","expected":[[1]],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[1],[2],[3]],"check":"unit chunks","expected":[[1],[2],[3]],"passed":true},{"actual":[],"check":"single width","expected":[[4]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"partial tail\", \"actual\": [[0], [1]], \"expected\": [[0], [1]], \"passed\": true}, {\"check\": \"exact multiple\", \"actual\": [[0], [1]], \"expected\": [[0], [1]], \"passed\": true}, {\"check\": \"short singleton\", \"actual\": [], \"expected\": [[1]], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"unit chunks\", \"actual\": [[1], [2], [3]], \"expected\": [[1], [2], [3]], \"passed\": true}, {\"check\": \"single width\", \"actual\": [], \"expected\": [[4]], \"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."}}