{"abstract":"Dot product silently drops unmatched tail.","category":"Model quantization arithmetic","checks":6,"contract":"Both vectors must have exactly the declared length. Return None if either length differs; otherwise compute the zero-point-centered integer dot product.","contract_signature":"a, b, zero_a, zero_b, length","evaluation_group":"quant-dot_centering","failed_approach":"The attempted repair checks the left vector length only; a short right vector still gets silently truncated by the zip-style accumulation.","family":"w3-model-quantization-arithmetic-dot-length","id":"FA-98721","implementations":{"attempt":{"sha256":"25e83f8ffb043a5b6dbc4fd59fc8c028606c0ad307ab6105123bf040880115f2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(a, b, zero_a, zero_b, length):\n    if len(a)!=length: return None\n    return sum((a[i]-zero_a)*(b[i]-zero_b) for i in range(min(len(a),len(b))))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('equal declared lengths',solve([1,2],[3,4],0,0,2),11)\ncheck('left too long',solve([1,2,3],[4,5],0,0,2),None)\ncheck('right too long',solve([1],[2,3],0,0,1),None)\ncheck('both short',solve([1],[2],0,0,2),None)\ncheck('empty valid',solve([],[],N,N,0),0)\ncheck('singleton centered',solve([N+1],[N+2],N,N,1),2)\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":"46008924ff0e47f439387fccb0c9128687a2e954be7c4e1bf8a3dd0015570bb5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(a, b, zero_a, zero_b, length):\n    return sum((x-zero_a)*(y-zero_b) for x,y in zip(a,b))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('equal declared lengths',solve([1,2],[3,4],0,0,2),11)\ncheck('left too long',solve([1,2,3],[4,5],0,0,2),None)\ncheck('right too long',solve([1],[2,3],0,0,1),None)\ncheck('both short',solve([1],[2],0,0,2),None)\ncheck('empty valid',solve([],[],N,N,0),0)\ncheck('singleton centered',solve([N+1],[N+2],N,N,1),2)\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":"Toy scalar/list arithmetic only; it does not model a production quantizer, hardware instruction, or accuracy/performance gain. 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-model-quantization-arithmetic-dot-length","generated_at":"2026-09-30T16:48:16.280208+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic model isolates one quantization arithmetic contract from tensor storage and runtime kernels.","root_cause":"Vectors must have equal lengths; return None on mismatch, otherwise compute the zero-point-centered integer dot product.","sha256":"b4ae7c2899e2672d6a548105ce4c2cd609928ae82210532b2f86957c929cb877","title":"Quantization: Dot product silently drops unmatched tail · 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":26.651,"exit_code":1,"observations":[{"actual":11,"check":"equal declared lengths","expected":11,"passed":true},{"actual":null,"check":"left too long","expected":null,"passed":true},{"actual":2,"check":"right too long","expected":null,"passed":false},{"actual":null,"check":"both short","expected":null,"passed":true},{"actual":0,"check":"empty valid","expected":0,"passed":true},{"actual":2,"check":"singleton centered","expected":2,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"equal declared lengths\", \"actual\": 11, \"expected\": 11, \"passed\": true}, {\"check\": \"left too long\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"right too long\", \"actual\": 2, \"expected\": null, \"passed\": false}, {\"check\": \"both short\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"empty valid\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"singleton centered\", \"actual\": 2, \"expected\": 2, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.758,"exit_code":1,"observations":[{"actual":11,"check":"equal declared lengths","expected":11,"passed":true},{"actual":14,"check":"left too long","expected":null,"passed":false},{"actual":2,"check":"right too long","expected":null,"passed":false},{"actual":2,"check":"both short","expected":null,"passed":false},{"actual":0,"check":"empty valid","expected":0,"passed":true},{"actual":2,"check":"singleton centered","expected":2,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"equal declared lengths\", \"actual\": 11, \"expected\": 11, \"passed\": true}, {\"check\": \"left too long\", \"actual\": 14, \"expected\": null, \"passed\": false}, {\"check\": \"right too long\", \"actual\": 2, \"expected\": null, \"passed\": false}, {\"check\": \"both short\", \"actual\": 2, \"expected\": null, \"passed\": false}, {\"check\": \"empty valid\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"singleton centered\", \"actual\": 2, \"expected\": 2, \"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."}}