{"abstract":"Optimizer state follows list position instead of parameter identity.","category":"Optimizer update state","checks":6,"contract":"For records [id,p,g,m], update each record independently using m_next=.5*m+.5*g and p_next=p-m_next; preserve record order.","contract_signature":"records","evaluation_group":"optimizer-toy-parameter-state-pairing","failed_approach":"Replacing the mismatched prior moment with the current gradient removes cross-parameter borrowing but discards all stored history.","family":"w3-optimizer-update-state-parameter-state-pairing","id":"FA-98991","implementations":{"attempt":{"sha256":"0b5cc35d3ae13864311e55b71a0ee4008bbd563fb9197373382187620c368796","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(records):\n    return [[r[0],r[1]-(0.5*r[2]+0.5*r[2]),0.5*r[2]+0.5*r[2]] for r in records]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('two parameter state',solve([['a',10,2,4],['b',20,-2,0]]),[['a',7,3],['b',21,-1]])\ncheck('reordered records',solve([['b',20,-2,0],['a',10,2,4]]),[['b',21,-1],['a',7,3]])\ncheck('singleton',solve([['x',N,2,0]]),[['x',N-1,1]])\ncheck('empty records',solve([]),[])\ncheck('zero gradient preserves history',solve([['p',5,0,6]]),[['p',2,3]])\ncheck('distinct state values',solve([['u',0,4,2],['v',0,4,8]]),[['u',-3,3],['v',-6,6]])\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":"852290b9085d08dfd5c376a0e53010779250f9fc01ea880f759080497b5f67ca","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(records):\n    states=[r[3] for r in sorted(records,key=lambda r:r[0])]\n    return [[r[0],r[1]-(0.5*r[2]+0.5*m),0.5*r[2]+0.5*m] for r,m in zip(records,states)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('two parameter state',solve([['a',10,2,4],['b',20,-2,0]]),[['a',7,3],['b',21,-1]])\ncheck('reordered records',solve([['b',20,-2,0],['a',10,2,4]]),[['b',21,-1],['a',7,3]])\ncheck('singleton',solve([['x',N,2,0]]),[['x',N-1,1]])\ncheck('empty records',solve([]),[])\ncheck('zero gradient preserves history',solve([['p',5,0,6]]),[['p',2,3]])\ncheck('distinct state values',solve([['u',0,4,2],['v',0,4,8]]),[['u',-3,3],['v',-6,6]])\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":"These are deterministic scalar or short-vector toy contracts, not claims about production optimizer APIs or training quality. 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-optimizer-update-state-parameter-state-pairing","generated_at":"2026-09-30T16:48:18.999897+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Optimizer implementations must associate each parameter with its own mathematically specified update state.","root_cause":"Moments are sorted by parameter ID and then paired positionally with parameters that retain their input order.","sha256":"e44a6a280885b50b8971ec1ca320346c40b58ad46e1c4131f5357bb6f315b7c6","title":"Optimizer state follows list position instead of parameter identity · 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":30.375,"exit_code":1,"observations":[{"actual":[["a",8.0,2.0],["b",22.0,-2.0]],"check":"two parameter state","expected":[["a",7,3],["b",21,-1]],"passed":false},{"actual":[["b",22.0,-2.0],["a",8.0,2.0]],"check":"reordered records","expected":[["b",21,-1],["a",7,3]],"passed":false},{"actual":[["x",-1.0,2.0]],"check":"singleton","expected":[["x",0,1]],"passed":false},{"actual":[],"check":"empty records","expected":[],"passed":true},{"actual":[["p",5.0,0.0]],"check":"zero gradient preserves history","expected":[["p",2,3]],"passed":false},{"actual":[["u",-4.0,4.0],["v",-4.0,4.0]],"check":"distinct state values","expected":[["u",-3,3],["v",-6,6]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"two parameter state\", \"actual\": [[\"a\", 8.0, 2.0], [\"b\", 22.0, -2.0]], \"expected\": [[\"a\", 7, 3], [\"b\", 21, -1]], \"passed\": false}, {\"check\": \"reordered records\", \"actual\": [[\"b\", 22.0, -2.0], [\"a\", 8.0, 2.0]], \"expected\": [[\"b\", 21, -1], [\"a\", 7, 3]], \"passed\": false}, {\"check\": \"singleton\", \"actual\": [[\"x\", -1.0, 2.0]], \"expected\": [[\"x\", 0, 1]], \"passed\": false}, {\"check\": \"empty records\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"zero gradient preserves history\", \"actual\": [[\"p\", 5.0, 0.0]], \"expected\": [[\"p\", 2, 3]], \"passed\": false}, {\"check\": \"distinct state values\", \"actual\": [[\"u\", -4.0, 4.0], [\"v\", -4.0, 4.0]], \"expected\": [[\"u\", -3, 3], [\"v\", -6, 6]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":31.375,"exit_code":1,"observations":[{"actual":[["a",7.0,3.0],["b",21.0,-1.0]],"check":"two parameter state","expected":[["a",7,3],["b",21,-1]],"passed":true},{"actual":[["b",19.0,1.0],["a",9.0,1.0]],"check":"reordered records","expected":[["b",21,-1],["a",7,3]],"passed":false},{"actual":[["x",0.0,1.0]],"check":"singleton","expected":[["x",0,1]],"passed":true},{"actual":[],"check":"empty records","expected":[],"passed":true},{"actual":[["p",2.0,3.0]],"check":"zero gradient preserves history","expected":[["p",2,3]],"passed":true},{"actual":[["u",-3.0,3.0],["v",-6.0,6.0]],"check":"distinct state values","expected":[["u",-3,3],["v",-6,6]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"two parameter state\", \"actual\": [[\"a\", 7.0, 3.0], [\"b\", 21.0, -1.0]], \"expected\": [[\"a\", 7, 3], [\"b\", 21, -1]], \"passed\": true}, {\"check\": \"reordered records\", \"actual\": [[\"b\", 19.0, 1.0], [\"a\", 9.0, 1.0]], \"expected\": [[\"b\", 21, -1], [\"a\", 7, 3]], \"passed\": false}, {\"check\": \"singleton\", \"actual\": [[\"x\", 0.0, 1.0]], \"expected\": [[\"x\", 0, 1]], \"passed\": true}, {\"check\": \"empty records\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"zero gradient preserves history\", \"actual\": [[\"p\", 2.0, 3.0]], \"expected\": [[\"p\", 2, 3]], \"passed\": true}, {\"check\": \"distinct state values\", \"actual\": [[\"u\", -3.0, 3.0], [\"v\", -6.0, 6.0]], \"expected\": [[\"u\", -3, 3], [\"v\", -6, 6]], \"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."}}