{"abstract":"Linear decay uses the full horizon after warmup.","category":"Learning rate schedules","checks":6,"contract":"Ramp to base through warmup, then linearly reach zero at total.","contract_signature":"step, base, warmup, total","evaluation_group":"lr-schedule-warmup-then-linear","failed_approach":"Correcting the denominator alone allows negative rates after the schedule end.","family":"w3-learning-rate-schedules-warmup-then-linear","id":"FA-99086","implementations":{"attempt":{"sha256":"fe232e0e386835ab623127843247b8d991e711423b6438d63907349c5da89021","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(step, base, warmup, total):\n    return base*step/warmup if step<warmup else base*(total-step)/(total-warmup)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('warmup start',solve(0,8,2,6),0); check('warmup middle',solve(1,8,2,6),4); check('boundary',solve(2,8,2,6),8); check('decay middle',solve(4,8,2,6),4); check('end',solve(6,8,2,6),0); check('after',solve(7,8,2,6),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":"d5bdff508bb4ca062b64ede2b32f14562356ed8b707082bd9e886ae9b8ee448a","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(step, base, warmup, total):\n    return base*step/warmup if step<warmup else base*(total-step)/total\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('warmup start',solve(0,8,2,6),0); check('warmup middle',solve(1,8,2,6),4); check('boundary',solve(2,8,2,6),8); check('decay middle',solve(4,8,2,6),4); check('end',solve(6,8,2,6),0); check('after',solve(7,8,2,6),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":"These are toy scalar contracts with integer steps and finite parameters; they do not model framework defaults or optimizer state. 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-learning-rate-schedules-warmup-then-linear","generated_at":"2026-09-30T16:48:20.350711+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic scalar schedule makes step-to-rate mapping explicit for a small training loop.","root_cause":"The decay numerator is divided by the full horizon despite starting after warmup.","sha256":"d07e083da61282c239964d1cb93ff6d07c699403aa97a935f64bb7130c5b21aa","title":"Linear decay uses the full horizon after warmup · case 01","variant":1,"variant_policy":"The same explicitly authored fixtures repeat across all five numbered records; runtime N is unused. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":28.391,"exit_code":1,"observations":[{"actual":0.0,"check":"warmup start","expected":0,"passed":true},{"actual":4.0,"check":"warmup middle","expected":4,"passed":true},{"actual":8.0,"check":"boundary","expected":8,"passed":true},{"actual":4.0,"check":"decay middle","expected":4,"passed":true},{"actual":0.0,"check":"end","expected":0,"passed":true},{"actual":-2.0,"check":"after","expected":0,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"warmup start\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}, {\"check\": \"warmup middle\", \"actual\": 4.0, \"expected\": 4, \"passed\": true}, {\"check\": \"boundary\", \"actual\": 8.0, \"expected\": 8, \"passed\": true}, {\"check\": \"decay middle\", \"actual\": 4.0, \"expected\": 4, \"passed\": true}, {\"check\": \"end\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}, {\"check\": \"after\", \"actual\": -2.0, \"expected\": 0, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":28.541,"exit_code":1,"observations":[{"actual":0.0,"check":"warmup start","expected":0,"passed":true},{"actual":4.0,"check":"warmup middle","expected":4,"passed":true},{"actual":5.333333333333333,"check":"boundary","expected":8,"passed":false},{"actual":2.6666666666666665,"check":"decay middle","expected":4,"passed":false},{"actual":0.0,"check":"end","expected":0,"passed":true},{"actual":-1.3333333333333333,"check":"after","expected":0,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"warmup start\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}, {\"check\": \"warmup middle\", \"actual\": 4.0, \"expected\": 4, \"passed\": true}, {\"check\": \"boundary\", \"actual\": 5.333333333333333, \"expected\": 8, \"passed\": false}, {\"check\": \"decay middle\", \"actual\": 2.6666666666666665, \"expected\": 4, \"passed\": false}, {\"check\": \"end\", \"actual\": 0.0, \"expected\": 0, \"passed\": true}, {\"check\": \"after\", \"actual\": -1.3333333333333333, \"expected\": 0, \"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."}}