|  | import torch | 
|  | from torch import Tensor | 
|  | from .optimizer import (Optimizer, _use_grad_for_differentiable, _get_value, _dispatch_sqrt, | 
|  | _stack_if_compiling, _capturable_doc, _differentiable_doc, _foreach_doc, | 
|  | _fused_doc, _maximize_doc, _default_to_fused_or_foreach) | 
|  | from typing import List, Optional | 
|  | from torch.utils._foreach_utils import _group_tensors_by_device_and_dtype | 
|  |  | 
|  | __all__ = ["AdamW", "adamw"] | 
|  |  | 
|  |  | 
|  | class AdamW(Optimizer): | 
|  | def __init__( | 
|  | self, | 
|  | params, | 
|  | lr=1e-3, | 
|  | betas=(0.9, 0.999), | 
|  | eps=1e-8, | 
|  | weight_decay=1e-2, | 
|  | amsgrad=False, | 
|  | *, | 
|  | maximize: bool = False, | 
|  | foreach: Optional[bool] = None, | 
|  | capturable: bool = False, | 
|  | differentiable: bool = False, | 
|  | fused: Optional[bool] = None, | 
|  | ): | 
|  | if not 0.0 <= lr: | 
|  | raise ValueError("Invalid learning rate: {}".format(lr)) | 
|  | if not 0.0 <= eps: | 
|  | raise ValueError("Invalid epsilon value: {}".format(eps)) | 
|  | if not 0.0 <= betas[0] < 1.0: | 
|  | raise ValueError("Invalid beta parameter at index 0: {}".format(betas[0])) | 
|  | if not 0.0 <= betas[1] < 1.0: | 
|  | raise ValueError("Invalid beta parameter at index 1: {}".format(betas[1])) | 
|  | if not 0.0 <= weight_decay: | 
|  | raise ValueError("Invalid weight_decay value: {}".format(weight_decay)) | 
|  | defaults = dict( | 
|  | lr=lr, | 
|  | betas=betas, | 
|  | eps=eps, | 
|  | weight_decay=weight_decay, | 
|  | amsgrad=amsgrad, | 
|  | foreach=foreach, | 
|  | maximize=maximize, | 
|  | capturable=capturable, | 
|  | differentiable=differentiable, | 
|  | fused=fused, | 
|  | ) | 
|  | super().__init__(params, defaults) | 
|  |  | 
|  | if fused: | 
|  | if differentiable: | 
|  | raise RuntimeError("`fused` does not support `differentiable`") | 
|  | self._step_supports_amp_scaling = True | 
|  | # TODO(crcrpar): [low prec params & their higher prec copy] | 
|  | # Suppor AMP with FP16/BF16 model params which would need | 
|  | # higher prec copy of params to do update math in higher prec to | 
|  | # alleviate the loss of information. | 
|  | if not all( | 
|  | p.is_cuda and torch.is_floating_point(p) | 
|  | for pg in self.param_groups for p in pg['params'] | 
|  | ): | 
|  | raise RuntimeError("`fused=True` requires all the params to be CUDA, floating point Tensor") | 
|  | if foreach: | 
|  | raise RuntimeError("`fused` and `foreach` cannot be `True` together.") | 
|  |  | 
|  | def __setstate__(self, state): | 
|  | super().__setstate__(state) | 
|  | for group in self.param_groups: | 
|  | group.setdefault("amsgrad", False) | 
|  | group.setdefault("maximize", False) | 
|  | group.setdefault("foreach", None) | 
|  | group.setdefault("capturable", False) | 
|  | group.setdefault("differentiable", False) | 
|  | group.setdefault("fused", None) | 
|  | state_values = list(self.state.values()) | 
|  | step_is_tensor = (len(state_values) != 0) and torch.is_tensor( | 
|  | state_values[0]["step"] | 
|  | ) | 
|  | if not step_is_tensor: | 
|  | for s in state_values: | 
|  | s["step"] = torch.tensor(float(s["step"])) | 
|  |  | 
|  | def _init_group( | 
|  | self, | 
|  | group, | 
|  | params_with_grad, | 
|  | grads, | 
|  | amsgrad, | 
|  | exp_avgs, | 
|  | exp_avg_sqs, | 
|  | max_exp_avg_sqs, | 
|  | state_steps, | 
|  | ): | 
|  | for p in group["params"]: | 
|  | if p.grad is None: | 
|  | continue | 
|  | params_with_grad.append(p) | 
|  | if p.grad.is_sparse: | 
|  | raise RuntimeError("AdamW does not support sparse gradients") | 
|  | grads.append(p.grad) | 
|  |  | 
|  | state = self.state[p] | 
|  |  | 
|  | # State initialization | 
|  | if len(state) == 0: | 
|  | # note(crcrpar): Deliberately host `step` on CPU if both capturable and fused are off. | 
|  | # This is because kernel launches are costly on CUDA and XLA. | 
|  | state["step"] = ( | 
|  | torch.zeros((), dtype=torch.float, device=p.device) | 
|  | if group["capturable"] or group["fused"] | 
|  | else torch.tensor(0.0) | 
|  | ) | 
|  | # Exponential moving average of gradient values | 
|  | state["exp_avg"] = torch.zeros_like( | 
|  | p, memory_format=torch.preserve_format | 
|  | ) | 
|  | # Exponential moving average of squared gradient values | 
|  | state["exp_avg_sq"] = torch.zeros_like( | 
|  | p, memory_format=torch.preserve_format | 
|  | ) | 
|  | if amsgrad: | 
|  | # Maintains max of all exp. moving avg. of sq. grad. values | 
|  | state["max_exp_avg_sq"] = torch.zeros_like( | 
|  | p, memory_format=torch.preserve_format | 
|  | ) | 
|  |  | 
|  | exp_avgs.append(state["exp_avg"]) | 
|  | exp_avg_sqs.append(state["exp_avg_sq"]) | 
|  |  | 
|  | if amsgrad: | 
|  | max_exp_avg_sqs.append(state["max_exp_avg_sq"]) | 
|  |  | 
|  | state_steps.append(state["step"]) | 
|  |  | 
|  | @_use_grad_for_differentiable | 
|  | def step(self, closure=None): | 
|  | """Performs a single optimization step. | 
|  |  | 
|  | Args: | 
|  | closure (Callable, optional): A closure that reevaluates the model | 
|  | and returns the loss. | 
|  | """ | 
|  | self._cuda_graph_capture_health_check() | 
|  |  | 
|  | loss = None | 
|  | if closure is not None: | 
|  | with torch.enable_grad(): | 
|  | loss = closure() | 
|  |  | 
|  | for group in self.param_groups: | 
|  | params_with_grad = [] | 
|  | grads = [] | 
|  | exp_avgs = [] | 
|  | exp_avg_sqs = [] | 
|  | max_exp_avg_sqs = [] | 
|  | state_steps = [] | 
|  | amsgrad = group["amsgrad"] | 
|  | beta1, beta2 = group["betas"] | 
|  |  | 
|  | self._init_group( | 
|  | group, | 
|  | params_with_grad, | 
|  | grads, | 
|  | amsgrad, | 
|  | exp_avgs, | 
|  | exp_avg_sqs, | 
|  | max_exp_avg_sqs, | 
|  | state_steps, | 
|  | ) | 
|  |  | 
|  | adamw( | 
|  | params_with_grad, | 
|  | grads, | 
|  | exp_avgs, | 
|  | exp_avg_sqs, | 
|  | max_exp_avg_sqs, | 
|  | state_steps, | 
|  | amsgrad=amsgrad, | 
|  | beta1=beta1, | 
|  | beta2=beta2, | 
|  | lr=group["lr"], | 
|  | weight_decay=group["weight_decay"], | 
|  | eps=group["eps"], | 
|  | maximize=group["maximize"], | 
|  | foreach=group["foreach"], | 
|  | capturable=group["capturable"], | 
|  | differentiable=group["differentiable"], | 
|  | fused=group["fused"], | 
|  | grad_scale=getattr(self, "grad_scale", None), | 
|  | found_inf=getattr(self, "found_inf", None), | 
|  | ) | 
|  |  | 
|  | return loss | 
|  |  | 
|  |  | 
|  | AdamW.__doc__ = r"""Implements AdamW algorithm. | 
|  |  | 
|  | .. math:: | 
|  | \begin{aligned} | 
|  | &\rule{110mm}{0.4pt}                                                                 \\ | 
|  | &\textbf{input}      : \gamma \text{(lr)}, \: \beta_1, \beta_2 | 
|  | \text{(betas)}, \: \theta_0 \text{(params)}, \: f(\theta) \text{(objective)}, | 
|  | \: \epsilon \text{ (epsilon)}                                                    \\ | 
|  | &\hspace{13mm}      \lambda \text{(weight decay)},  \: \textit{amsgrad}, | 
|  | \: \textit{maximize}                                                             \\ | 
|  | &\textbf{initialize} : m_0 \leftarrow 0 \text{ (first moment)}, v_0 \leftarrow 0 | 
|  | \text{ ( second moment)}, \: \widehat{v_0}^{max}\leftarrow 0              \\[-1.ex] | 
|  | &\rule{110mm}{0.4pt}                                                                 \\ | 
|  | &\textbf{for} \: t=1 \: \textbf{to} \: \ldots \: \textbf{do}                         \\ | 
|  |  | 
|  | &\hspace{5mm}\textbf{if} \: \textit{maximize}:                                       \\ | 
|  | &\hspace{10mm}g_t           \leftarrow   -\nabla_{\theta} f_t (\theta_{t-1})          \\ | 
|  | &\hspace{5mm}\textbf{else}                                                           \\ | 
|  | &\hspace{10mm}g_t           \leftarrow   \nabla_{\theta} f_t (\theta_{t-1})           \\ | 
|  | &\hspace{5mm} \theta_t \leftarrow \theta_{t-1} - \gamma \lambda \theta_{t-1}         \\ | 
|  | &\hspace{5mm}m_t           \leftarrow   \beta_1 m_{t-1} + (1 - \beta_1) g_t          \\ | 
|  | &\hspace{5mm}v_t           \leftarrow   \beta_2 v_{t-1} + (1-\beta_2) g^2_t          \\ | 
|  | &\hspace{5mm}\widehat{m_t} \leftarrow   m_t/\big(1-\beta_1^t \big)                   \\ | 
|  | &\hspace{5mm}\widehat{v_t} \leftarrow   v_t/\big(1-\beta_2^t \big)                   \\ | 
|  | &\hspace{5mm}\textbf{if} \: amsgrad                                                  \\ | 
|  | &\hspace{10mm}\widehat{v_t}^{max} \leftarrow \mathrm{max}(\widehat{v_t}^{max}, | 
|  | \widehat{v_t})                                                                   \\ | 
|  | &\hspace{10mm}\theta_t \leftarrow \theta_t - \gamma \widehat{m_t}/ | 
|  | \big(\sqrt{\widehat{v_t}^{max}} + \epsilon \big)                                 \\ | 
|  | &\hspace{5mm}\textbf{else}                                                           \\ | 
|  | &\hspace{10mm}\theta_t \leftarrow \theta_t - \gamma \widehat{m_t}/ | 
|  | \big(\sqrt{\widehat{v_t}} + \epsilon \big)                                       \\ | 
|  | &\rule{110mm}{0.4pt}                                                          \\[-1.ex] | 
|  | &\bf{return} \:  \theta_t                                                     \\[-1.ex] | 
|  | &\rule{110mm}{0.4pt}                                                          \\[-1.ex] | 
|  | \end{aligned} | 
|  |  | 
|  | For further details regarding the algorithm we refer to `Decoupled Weight Decay Regularization`_. | 
|  | """ + r""" | 
|  | Args: | 
|  | params (iterable): iterable of parameters to optimize or dicts defining | 
|  | parameter groups | 
|  | lr (float, optional): learning rate (default: 1e-3) | 
|  | betas (Tuple[float, float], optional): coefficients used for computing | 
|  | running averages of gradient and its square (default: (0.9, 0.999)) | 
|  | eps (float, optional): term added to the denominator to improve | 
|  | numerical stability (default: 1e-8) | 
|  | weight_decay (float, optional): weight decay coefficient (default: 1e-2) | 
|  | amsgrad (bool, optional): whether to use the AMSGrad variant of this | 
|  | algorithm from the paper `On the Convergence of Adam and Beyond`_ | 
|  | (default: False) | 
|  | {maximize} | 
|  | {foreach} | 
|  | {capturable} | 
|  | {differentiable} | 
|  | {fused} | 
|  | .. _Decoupled Weight Decay Regularization: | 
|  | https://arxiv.org/abs/1711.05101 | 
|  | .. _On the Convergence of Adam and Beyond: | 
|  | https://openreview.net/forum?id=ryQu7f-RZ | 
|  |  | 
|  | """.format(maximize=_maximize_doc, | 
|  | foreach=_foreach_doc, | 
|  | fused=_fused_doc, | 
|  | capturable=_capturable_doc, | 
|  | differentiable=_differentiable_doc) | 
|  |  | 
|  |  | 
|  | def adamw( | 
|  | params: List[Tensor], | 
|  | grads: List[Tensor], | 
|  | exp_avgs: List[Tensor], | 
|  | exp_avg_sqs: List[Tensor], | 
|  | max_exp_avg_sqs: List[Tensor], | 
|  | state_steps: List[Tensor], | 
|  | # kwonly args with defaults are not supported by functions compiled with torchscript issue #70627 | 
|  | # setting this as kwarg for now as functional API is compiled by torch/distributed/optim | 
|  | foreach: Optional[bool] = None, | 
|  | capturable: bool = False, | 
|  | differentiable: bool = False, | 
|  | fused: Optional[bool] = None, | 
|  | grad_scale: Optional[Tensor] = None, | 
|  | found_inf: Optional[Tensor] = None, | 
|  | *, | 
|  | amsgrad: bool, | 
|  | beta1: float, | 
|  | beta2: float, | 
|  | lr: float, | 
|  | weight_decay: float, | 
|  | eps: float, | 
|  | maximize: bool, | 
|  | ): | 
|  | r"""Functional API that performs AdamW algorithm computation. | 
|  |  | 
|  | See :class:`~torch.optim.AdamW` for details. | 
|  | """ | 
|  |  | 
|  | if not all(isinstance(t, torch.Tensor) for t in state_steps): | 
|  | raise RuntimeError( | 
|  | "API has changed, `state_steps` argument must contain a list of singleton tensors" | 
|  | ) | 
|  |  | 
|  | # Respect when the user inputs False/True for foreach or fused. We only want to change | 
|  | # the default when neither have been user-specified. Note that we default to foreach | 
|  | # and pass False to use_fused. This is not a mistake--we want to give the fused impl | 
|  | # bake-in time before making it the default, even if it is typically faster. | 
|  | if fused is None and foreach is None: | 
|  | _, foreach = _default_to_fused_or_foreach(params, differentiable, use_fused=False) | 
|  | if fused is None: | 
|  | fused = False | 
|  | if foreach is None: | 
|  | foreach = False | 
|  |  | 
|  | if foreach and torch.jit.is_scripting(): | 
|  | raise RuntimeError("torch.jit.script not supported with foreach optimizers") | 
|  | if fused and torch.jit.is_scripting(): | 
|  | raise RuntimeError("torch.jit.script not supported with fused optimizers") | 
|  |  | 
|  | if fused and not torch.jit.is_scripting(): | 
|  | func = _fused_adamw | 
|  | elif foreach and not torch.jit.is_scripting(): | 
|  | func = _multi_tensor_adamw | 
|  | else: | 
|  | func = _single_tensor_adamw | 
|  |  | 
|  | func( | 
|  | params, | 
|  | grads, | 
|  | exp_avgs, | 
|  | exp_avg_sqs, | 
|  | max_exp_avg_sqs, | 
|  | state_steps, | 
|  | amsgrad=amsgrad, | 
|  | beta1=beta1, | 
|  | beta2=beta2, | 
|  | lr=lr, | 
|  | weight_decay=weight_decay, | 
|  | eps=eps, | 
|  | maximize=maximize, | 
|  | capturable=capturable, | 
|  | differentiable=differentiable, | 
|  | grad_scale=grad_scale, | 
|  | found_inf=found_inf, | 
|  | ) | 
|  |  | 
|  |  | 
|  | def _single_tensor_adamw( | 
|  | params: List[Tensor], | 
|  | grads: List[Tensor], | 
|  | exp_avgs: List[Tensor], | 
|  | exp_avg_sqs: List[Tensor], | 
|  | max_exp_avg_sqs: List[Tensor], | 
|  | state_steps: List[Tensor], | 
|  | grad_scale: Optional[Tensor], | 
|  | found_inf: Optional[Tensor], | 
|  | *, | 
|  | amsgrad: bool, | 
|  | beta1: float, | 
|  | beta2: float, | 
|  | lr: float, | 
|  | weight_decay: float, | 
|  | eps: float, | 
|  | maximize: bool, | 
|  | capturable: bool, | 
|  | differentiable: bool, | 
|  | ): | 
|  |  | 
|  | assert grad_scale is None and found_inf is None | 
|  |  | 
|  | for i, param in enumerate(params): | 
|  | grad = grads[i] if not maximize else -grads[i] | 
|  | exp_avg = exp_avgs[i] | 
|  | exp_avg_sq = exp_avg_sqs[i] | 
|  | step_t = state_steps[i] | 
|  |  | 
|  | if capturable: | 
|  | assert ( | 
|  | param.is_cuda and step_t.is_cuda | 
|  | ), "If capturable=True, params and state_steps must be CUDA tensors." | 
|  |  | 
|  | if torch.is_complex(param): | 
|  | grad = torch.view_as_real(grad) | 
|  | exp_avg = torch.view_as_real(exp_avg) | 
|  | exp_avg_sq = torch.view_as_real(exp_avg_sq) | 
|  | param = torch.view_as_real(param) | 
|  |  | 
|  | # update step | 
|  | step_t += 1 | 
|  |  | 
|  | # Perform stepweight decay | 
|  | param.mul_(1 - lr * weight_decay) | 
|  |  | 
|  | # Decay the first and second moment running average coefficient | 
|  | exp_avg.mul_(beta1).add_(grad, alpha=1 - beta1) | 
|  | exp_avg_sq.mul_(beta2).addcmul_(grad, grad, value=1 - beta2) | 
|  |  | 
|  | if capturable or differentiable: | 
|  | step = step_t | 
|  |  | 
|  | # 1 - beta1 ** step can't be captured in a CUDA graph, even if step is a CUDA tensor | 
|  | # (incurs "RuntimeError: CUDA error: operation not permitted when stream is capturing") | 
|  | bias_correction1 = 1 - torch.pow(beta1, step) | 
|  | bias_correction2 = 1 - torch.pow(beta2, step) | 
|  |  | 
|  | step_size = lr / bias_correction1 | 
|  | step_size_neg = step_size.neg() | 
|  |  | 
|  | bias_correction2_sqrt = bias_correction2.sqrt() | 
|  |  | 
|  | if amsgrad: | 
|  | # Maintains the maximum of all 2nd moment running avg. till now | 
|  | if differentiable: | 
|  | max_exp_avg_sqs_i = max_exp_avg_sqs[i].clone() | 
|  | else: | 
|  | max_exp_avg_sqs_i = max_exp_avg_sqs[i] | 
|  | max_exp_avg_sqs[i].copy_(torch.maximum(max_exp_avg_sqs_i, exp_avg_sq)) | 
|  | # Uses the max. for normalizing running avg. of gradient | 
|  | # Folds in (admittedly ugly) 1-elem step_size math here to avoid extra param-set-sized read+write | 
|  | # (can't fold it into addcdiv_ below because addcdiv_ requires value is a Number, not a Tensor) | 
|  | denom = ( | 
|  | max_exp_avg_sqs[i].sqrt() / (bias_correction2_sqrt * step_size_neg) | 
|  | ).add_(eps / step_size_neg) | 
|  | else: | 
|  | denom = ( | 
|  | exp_avg_sq.sqrt() / (bias_correction2_sqrt * step_size_neg) | 
|  | ).add_(eps / step_size_neg) | 
|  |  | 
|  | param.addcdiv_(exp_avg, denom) | 
|  | else: | 
|  | step = _get_value(step_t) | 
|  |  | 
|  | bias_correction1 = 1 - beta1 ** step | 
|  | bias_correction2 = 1 - beta2 ** step | 
|  |  | 
|  | step_size = lr / bias_correction1 | 
|  |  | 
|  | bias_correction2_sqrt = _dispatch_sqrt(bias_correction2) | 
|  |  | 
|  | if amsgrad: | 
|  | # Maintains the maximum of all 2nd moment running avg. till now | 
|  | torch.maximum(max_exp_avg_sqs[i], exp_avg_sq, out=max_exp_avg_sqs[i]) | 
|  | # Use the max. for normalizing running avg. of gradient | 
|  | denom = (max_exp_avg_sqs[i].sqrt() / bias_correction2_sqrt).add_(eps) | 
|  | else: | 
|  | denom = (exp_avg_sq.sqrt() / bias_correction2_sqrt).add_(eps) | 
|  |  | 
|  | param.addcdiv_(exp_avg, denom, value=-step_size) | 
|  |  | 
|  |  | 
|  | def _multi_tensor_adamw( | 
|  | params: List[Tensor], | 
|  | grads: List[Tensor], | 
|  | exp_avgs: List[Tensor], | 
|  | exp_avg_sqs: List[Tensor], | 
|  | max_exp_avg_sqs: List[Tensor], | 
|  | state_steps: List[Tensor], | 
|  | grad_scale: Optional[Tensor], | 
|  | found_inf: Optional[Tensor], | 
|  | *, | 
|  | amsgrad: bool, | 
|  | beta1: float, | 
|  | beta2: float, | 
|  | lr: float, | 
|  | weight_decay: float, | 
|  | eps: float, | 
|  | maximize: bool, | 
|  | capturable: bool, | 
|  | differentiable: bool, | 
|  | ): | 
|  | if len(params) == 0: | 
|  | return | 
|  |  | 
|  | if capturable: | 
|  | assert all( | 
|  | p.is_cuda and step.is_cuda for p, step in zip(params, state_steps) | 
|  | ), "If capturable=True, params and state_steps must be CUDA tensors." | 
|  |  | 
|  | assert not differentiable, "_foreach ops don't support autograd" | 
|  |  | 
|  | assert grad_scale is None and found_inf is None | 
|  |  | 
|  | grouped_tensors = _group_tensors_by_device_and_dtype([ | 
|  | params, grads, exp_avgs, exp_avg_sqs, max_exp_avg_sqs, state_steps]) | 
|  | for (device_params, device_grads, device_exp_avgs, device_exp_avg_sqs, | 
|  | device_max_exp_avg_sqs, device_state_steps) in grouped_tensors.values(): | 
|  | if maximize: | 
|  | device_grads = torch._foreach_neg(tuple(device_grads))  # type: ignore[assignment] | 
|  |  | 
|  |  | 
|  | device_grads = [torch.view_as_real(x) if torch.is_complex(x) else x for x in device_grads] | 
|  | device_exp_avgs = [torch.view_as_real(x) if torch.is_complex(x) else x for x in device_exp_avgs] | 
|  | device_exp_avg_sqs = [ | 
|  | torch.view_as_real(x) if torch.is_complex(x) else x for x in device_exp_avg_sqs | 
|  | ] | 
|  | device_params = [torch.view_as_real(x) if torch.is_complex(x) else x for x in device_params] | 
|  |  | 
|  | # update steps | 
|  | torch._foreach_add_(device_state_steps, 1) | 
|  |  | 
|  | # Perform stepweight decay | 
|  | torch._foreach_mul_(device_params, 1 - lr * weight_decay) | 
|  |  | 
|  | # Decay the first and second moment running average coefficient | 
|  | torch._foreach_mul_(device_exp_avgs, beta1) | 
|  | torch._foreach_add_(device_exp_avgs, device_grads, alpha=1 - beta1) | 
|  |  | 
|  | torch._foreach_mul_(device_exp_avg_sqs, beta2) | 
|  | torch._foreach_addcmul_(device_exp_avg_sqs, device_grads, device_grads, 1 - beta2) | 
|  |  | 
|  | if capturable: | 
|  | bias_correction1 = torch._foreach_pow(beta1, device_state_steps) | 
|  | bias_correction2 = torch._foreach_pow(beta2, device_state_steps) | 
|  | # foreach_sub doesn't allow a scalar as the first arg | 
|  | torch._foreach_sub_(bias_correction1, 1) | 
|  | torch._foreach_sub_(bias_correction2, 1) | 
|  | torch._foreach_neg_(bias_correction1) | 
|  | torch._foreach_neg_(bias_correction2) | 
|  |  | 
|  | # foreach_div doesn't allow a scalar as the first arg | 
|  | step_size = torch._foreach_div(bias_correction1, lr) | 
|  | torch._foreach_reciprocal_(step_size) | 
|  | torch._foreach_neg_(step_size) | 
|  |  | 
|  | bias_correction2_sqrt = torch._foreach_sqrt(bias_correction2) | 
|  |  | 
|  | if amsgrad: | 
|  | # Maintains the maximum of all 2nd moment running avg. till now | 
|  | torch._foreach_maximum_(device_max_exp_avg_sqs, device_exp_avg_sqs) | 
|  |  | 
|  | # Use the max. for normalizing running avg. of gradient | 
|  | max_exp_avg_sq_sqrt = torch._foreach_sqrt(device_max_exp_avg_sqs) | 
|  | # Folds in (admittedly ugly) 1-elem step_size math here to avoid extra param-set-sized read+write | 
|  | # (can't fold it into addcdiv_ below because addcdiv_ requires value is a Number, not a Tensor) | 
|  | torch._foreach_div_( | 
|  | max_exp_avg_sq_sqrt, | 
|  | torch._foreach_mul(bias_correction2_sqrt, step_size), | 
|  | ) | 
|  | eps_over_step_size = torch._foreach_div(step_size, eps) | 
|  | torch._foreach_reciprocal_(eps_over_step_size) | 
|  | denom = torch._foreach_add(max_exp_avg_sq_sqrt, eps_over_step_size) | 
|  | else: | 
|  | exp_avg_sq_sqrt = torch._foreach_sqrt(device_exp_avg_sqs) | 
|  | torch._foreach_div_( | 
|  | exp_avg_sq_sqrt, torch._foreach_mul(bias_correction2_sqrt, step_size) | 
|  | ) | 
|  | eps_over_step_size = torch._foreach_div(step_size, eps) | 
|  | torch._foreach_reciprocal_(eps_over_step_size) | 
|  | denom = torch._foreach_add(exp_avg_sq_sqrt, eps_over_step_size) | 
|  |  | 
|  | torch._foreach_addcdiv_(device_params, device_exp_avgs, denom) | 
|  | else: | 
|  | bias_correction1 = [1 - beta1 ** _get_value(step) for step in device_state_steps] | 
|  | bias_correction2 = [1 - beta2 ** _get_value(step) for step in device_state_steps] | 
|  |  | 
|  | step_size = _stack_if_compiling([(lr / bc) * -1 for bc in bias_correction1]) | 
|  |  | 
|  | bias_correction2_sqrt = [_dispatch_sqrt(bc) for bc in bias_correction2] | 
|  |  | 
|  | if amsgrad: | 
|  | # Maintains the maximum of all 2nd moment running avg. till now | 
|  | torch._foreach_maximum_(device_max_exp_avg_sqs, device_exp_avg_sqs) | 
|  |  | 
|  | # Use the max. for normalizing running avg. of gradient | 
|  | max_exp_avg_sq_sqrt = torch._foreach_sqrt(device_max_exp_avg_sqs) | 
|  | torch._foreach_div_(max_exp_avg_sq_sqrt, bias_correction2_sqrt) | 
|  | denom = torch._foreach_add(max_exp_avg_sq_sqrt, eps) | 
|  | else: | 
|  | exp_avg_sq_sqrt = torch._foreach_sqrt(device_exp_avg_sqs) | 
|  | torch._foreach_div_(exp_avg_sq_sqrt, bias_correction2_sqrt) | 
|  | denom = torch._foreach_add(exp_avg_sq_sqrt, eps) | 
|  |  | 
|  | torch._foreach_addcdiv_(device_params, device_exp_avgs, denom, step_size) | 
|  |  | 
|  |  | 
|  | def _fused_adamw( | 
|  | params: List[Tensor], | 
|  | grads: List[Tensor], | 
|  | exp_avgs: List[Tensor], | 
|  | exp_avg_sqs: List[Tensor], | 
|  | max_exp_avg_sqs: List[Tensor], | 
|  | state_steps: List[Tensor], | 
|  | grad_scale: Optional[Tensor], | 
|  | found_inf: Optional[Tensor], | 
|  | *, | 
|  | amsgrad: bool, | 
|  | beta1: float, | 
|  | beta2: float, | 
|  | lr: float, | 
|  | weight_decay: float, | 
|  | eps: float, | 
|  | maximize: bool, | 
|  | capturable: bool,  # Needed for consistency. | 
|  | differentiable: bool, | 
|  | ) -> None: | 
|  | if differentiable: | 
|  | raise RuntimeError("_fused_adamw is not differentiable") | 
|  | grad_scale_dict = {grad_scale.device: grad_scale} if grad_scale is not None else None | 
|  | found_inf_dict = {found_inf.device: found_inf} if found_inf is not None else None | 
|  | grouped_tensors = _group_tensors_by_device_and_dtype([params, grads, exp_avgs, exp_avg_sqs, max_exp_avg_sqs, state_steps]) | 
|  | for (device, dtype) in grouped_tensors: | 
|  | ( | 
|  | device_params, | 
|  | device_grads, | 
|  | device_exp_avgs, | 
|  | device_exp_avg_sqs, | 
|  | device_max_exp_avg_sqs, | 
|  | device_state_steps, | 
|  | ) = grouped_tensors[(device, dtype)] | 
|  | device_grad_scale, device_found_inf = None, None | 
|  | if grad_scale is not None: | 
|  | if device not in grad_scale_dict: | 
|  | grad_scale_dict[device] = grad_scale.to(device, non_blocking=True) | 
|  | device_grad_scale = grad_scale_dict[device] | 
|  | if found_inf is not None: | 
|  | if found_inf not in found_inf_dict: | 
|  | found_inf_dict[device] = found_inf.to(device, non_blocking=True) | 
|  | device_found_inf = found_inf_dict[device] | 
|  | torch._foreach_add_(device_state_steps, 1) | 
|  | torch._fused_adamw_( | 
|  | device_params, | 
|  | device_grads, | 
|  | device_exp_avgs, | 
|  | device_exp_avg_sqs, | 
|  | device_max_exp_avg_sqs, | 
|  | device_state_steps, | 
|  | amsgrad=amsgrad, | 
|  | lr=lr, | 
|  | beta1=beta1, | 
|  | beta2=beta2, | 
|  | weight_decay=weight_decay, | 
|  | eps=eps, | 
|  | maximize=maximize, | 
|  | grad_scale=device_grad_scale, | 
|  | found_inf=device_found_inf, | 
|  | ) | 
|  | if device_found_inf is not None: | 
|  | torch._foreach_sub_(device_state_steps, [device_found_inf] * len(device_state_steps)) |