{"record":{"id":"3415a8c8b2cd69fa","repo":"huggingface/pytorch-image-models","slug":"invalid-beta-parameter-at-index-1-3415a8","errorCode":null,"errorMessage":"Invalid beta parameter at index 1: {}","messagePattern":"Invalid beta parameter at index 1: (.+?)","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"timm/optim/mars.py","lineNumber":119,"sourceCode":"            lr: float = 3e-3,\n            betas: Tuple[float, float] = (0.9, 0.99),\n            eps: float = 1e-8,\n            weight_decay: float = 0.,\n            gamma: float = 0.025,\n            mars_type: str = \"adamw\",\n            optimize_1d: bool = False,\n            lr_1d_factor: float = 1.0,\n            betas_1d: Optional[Tuple[float, float]] = None,\n            caution: bool = False\n    ):\n        if not 0.0 <= lr:\n            raise ValueError(\"Invalid learning rate: {}\".format(lr))\n        if not 0.0 <= eps:\n            raise ValueError(\"Invalid epsilon value: {}\".format(eps))\n        if not 0.0 <= betas[0] < 1.0:\n            raise ValueError(\"Invalid beta parameter at index 0: {}\".format(betas[0]))\n        if not 0.0 <= betas[1] < 1.0:\n            raise ValueError(\"Invalid beta parameter at index 1: {}\".format(betas[1]))\n        assert mars_type in [\"adamw\", \"lion\"], \"MARS type not supported\"\n\n        defaults = dict(\n            lr=lr,\n            betas=betas,\n            eps=eps,\n            weight_decay=weight_decay,\n            mars_type=mars_type,\n            gamma=gamma,\n            optimize_1d=optimize_1d,\n            lr_1d_factor=lr_1d_factor,\n            betas_1d=betas_1d or betas,\n            caution=caution,\n        )\n        super(Mars, self).__init__(params, defaults)\n\n    def __setstate__(self, state):\n        super(Mars, self).__setstate__(state)","sourceCodeStart":101,"sourceCodeEnd":137,"githubUrl":"https://github.com/huggingface/pytorch-image-models/blob/9a5261e31b3b5128526eb2658333b4c0a54464ae/timm/optim/mars.py#L101-L137","documentation":"Mars requires beta2 (betas[1]) to satisfy 0 <= beta2 < 1, matching the second-moment EMA decay constraint shared with Adam-family optimizers.","triggerScenarios":"Calling Mars(params, betas=(0.9, 1.0)) or betas=(0.9, 1.5); beta2=1 is rejected.","commonSituations":"Using beta2=1.0 intending 'long memory'; typos in YAML/JSON config; ordering mixups.","solutions":["Use beta2 in [0,1), e.g. 0.999","Double-check the tuple order is (beta1, beta2)","Fix the config source"],"exampleFix":"# before\nopt = Mars(model.parameters(), betas=(0.9, 1.0))\n# after\nopt = Mars(model.parameters(), betas=(0.9, 0.999))","handlingStrategy":"validation","validationCode":"b1, b2 = cfg.betas\nassert 0 <= b2 < 1, 'beta2 must be in [0,1)'","typeGuard":"def are_valid_betas(betas: tuple) -> bool:\n    return (len(betas) == 2 and all(isinstance(b, (int, float)) and 0 <= b < 1 for b in betas))","tryCatchPattern":null,"preventionTips":["Use standard (0.9, 0.999) defaults","Check betas_1d too when using optimize_1d"],"tags":["optimizer","mars","betas","hyperparameter-validation"],"backgroundTag":"hyperparameter-out-of-range","analyzedSha":"9a5261e31b3b5128526eb2658333b4c0a54464ae","analyzedAt":"2026-08-27T02:34:25.417Z","schemaVersion":2},"datasetVersion":"2026-08-27T03:17:27.898Z"}