| import torch |
| from torch import Tensor |
| |
| from .optimizer import Optimizer |
| from typing import List, Optional |
| |
| |
| class Adagrad(Optimizer): |
| r"""Implements Adagrad algorithm. |
| |
| .. math:: |
| \begin{aligned} |
| &\rule{110mm}{0.4pt} \\ |
| &\textbf{input} : \gamma \text{ (lr)}, \: \theta_0 \text{ (params)}, \: f(\theta) |
| \text{ (objective)}, \: \lambda \text{ (weight decay)}, \\ |
| &\hspace{12mm} \tau \text{ (initial accumulator value)}, \: \eta\text{ (lr decay)}\\ |
| &\textbf{initialize} : state\_sum_0 \leftarrow 0 \\[-1.ex] |
| &\rule{110mm}{0.4pt} \\ |
| &\textbf{for} \: t=1 \: \textbf{to} \: \ldots \: \textbf{do} \\ |
| &\hspace{5mm}g_t \leftarrow \nabla_{\theta} f_t (\theta_{t-1}) \\ |
| &\hspace{5mm} \tilde{\gamma} \leftarrow \gamma / (1 +(t-1) \eta) \\ |
| &\hspace{5mm} \textbf{if} \: \lambda \neq 0 \\ |
| &\hspace{10mm} g_t \leftarrow g_t + \lambda \theta_{t-1} \\ |
| &\hspace{5mm}state\_sum_t \leftarrow state\_sum_{t-1} + g^2_t \\ |
| &\hspace{5mm}\theta_t \leftarrow |
| \theta_{t-1}- \tilde{\gamma} \frac{g_t}{\sqrt{state\_sum_t}+\epsilon} \\ |
| &\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 `Adaptive Subgradient Methods for Online Learning |
| and Stochastic Optimization`_. |
| |
| Args: |
| params (iterable): iterable of parameters to optimize or dicts defining |
| parameter groups |
| lr (float, optional): learning rate (default: 1e-2) |
| lr_decay (float, optional): learning rate decay (default: 0) |
| weight_decay (float, optional): weight decay (L2 penalty) (default: 0) |
| eps (float, optional): term added to the denominator to improve |
| numerical stability (default: 1e-10) |
| foreach (bool, optional): whether foreach implementation of optimizer is used (default: None) |
| |
| .. _Adaptive Subgradient Methods for Online Learning and Stochastic |
| Optimization: http://jmlr.org/papers/v12/duchi11a.html |
| """ |
| |
| def __init__(self, params, lr=1e-2, lr_decay=0, weight_decay=0, initial_accumulator_value=0, |
| eps=1e-10, foreach: Optional[bool] = None): |
| if not 0.0 <= lr: |
| raise ValueError("Invalid learning rate: {}".format(lr)) |
| if not 0.0 <= lr_decay: |
| raise ValueError("Invalid lr_decay value: {}".format(lr_decay)) |
| if not 0.0 <= weight_decay: |
| raise ValueError("Invalid weight_decay value: {}".format(weight_decay)) |
| if not 0.0 <= initial_accumulator_value: |
| raise ValueError("Invalid initial_accumulator_value value: {}".format(initial_accumulator_value)) |
| if not 0.0 <= eps: |
| raise ValueError("Invalid epsilon value: {}".format(eps)) |
| |
| defaults = dict(lr=lr, lr_decay=lr_decay, eps=eps, weight_decay=weight_decay, |
| initial_accumulator_value=initial_accumulator_value, foreach=foreach) |
| super(Adagrad, self).__init__(params, defaults) |
| |
| for group in self.param_groups: |
| for p in group['params']: |
| state = self.state[p] |
| state['step'] = torch.tensor(0.) |
| init_value = complex(initial_accumulator_value, initial_accumulator_value) if torch.is_complex(p) \ |
| else initial_accumulator_value |
| state['sum'] = torch.full_like(p, init_value, memory_format=torch.preserve_format) |
| |
| def __setstate__(self, state): |
| super().__setstate__(state) |
| for group in self.param_groups: |
| group.setdefault('foreach', 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 share_memory(self): |
| for group in self.param_groups: |
| for p in group['params']: |
| state = self.state[p] |
| state['sum'].share_memory_() |
| |
| @torch.no_grad() |
| def step(self, closure=None): |
| """Performs a single optimization step. |
| |
| Args: |
| closure (callable, optional): A closure that reevaluates the model |
| and returns the loss. |
| """ |
| loss = None |
| |
| if closure is not None: |
| with torch.enable_grad(): |
| loss = closure() |
| |
| for group in self.param_groups: |
| params_with_grad = [] |
| grads = [] |
| state_sums = [] |
| state_steps = [] |
| |
| has_sparse_grad = False |
| for p in group['params']: |
| if p.grad is not None: |
| if p.grad.is_sparse: |
| has_sparse_grad = True |
| params_with_grad.append(p) |
| grads.append(p.grad) |
| state = self.state[p] |
| state_sums.append(state['sum']) |
| state_steps.append(state['step']) |
| |
| adagrad(params_with_grad, |
| grads, |
| state_sums, |
| state_steps, |
| lr=group['lr'], |
| weight_decay=group['weight_decay'], |
| lr_decay=group['lr_decay'], |
| eps=group['eps'], |
| has_sparse_grad=has_sparse_grad, |
| foreach=group['foreach']) |
| |
| return loss |
| |
| |
| def adagrad(params: List[Tensor], |
| grads: List[Tensor], |
| state_sums: List[Tensor], |
| state_steps: List[Tensor], |
| # kwonly args with defaults are not supported by functions compiled with torchscript issue #70627 |
| # setting these as kwargs for now as functional API is compiled by torch/distributed/optim |
| has_sparse_grad: bool = None, |
| foreach: bool = None, |
| *, |
| lr: float, |
| weight_decay: float, |
| lr_decay: float, |
| eps: float): |
| r"""Functional API that performs Adagrad algorithm computation. |
| |
| See :class:`~torch.optim.Adagrad` 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") |
| |
| if foreach is None: |
| # Placeholder for more complex foreach logic to be added when value is not set |
| foreach = False |
| |
| if foreach and torch.jit.is_scripting(): |
| raise RuntimeError('torch.jit.script not supported with foreach optimizers') |
| |
| if foreach and not torch.jit.is_scripting(): |
| func = _multi_tensor_adagrad |
| else: |
| func = _single_tensor_adagrad |
| |
| func(params, |
| grads, |
| state_sums, |
| state_steps, |
| lr=lr, |
| weight_decay=weight_decay, |
| lr_decay=lr_decay, |
| eps=eps, |
| has_sparse_grad=has_sparse_grad) |
| |
| |
| def _make_sparse(grad, grad_indices, values): |
| size = grad.size() |
| if grad_indices.numel() == 0 or values.numel() == 0: |
| return torch.empty_like(grad) |
| return torch.sparse_coo_tensor(grad_indices, values, size) |
| |
| |
| def _single_tensor_adagrad(params: List[Tensor], |
| grads: List[Tensor], |
| state_sums: List[Tensor], |
| state_steps: List[Tensor], |
| *, |
| lr: float, |
| weight_decay: float, |
| lr_decay: float, |
| eps: float, |
| has_sparse_grad: bool): |
| |
| for (param, grad, state_sum, step_t) in zip(params, grads, state_sums, state_steps): |
| # update step |
| step_t += 1 |
| step = step_t.item() |
| |
| if weight_decay != 0: |
| if grad.is_sparse: |
| raise RuntimeError("weight_decay option is not compatible with sparse gradients") |
| grad = grad.add(param, alpha=weight_decay) |
| |
| clr = lr / (1 + (step - 1) * lr_decay) |
| |
| if grad.is_sparse: |
| grad = grad.coalesce() # the update is non-linear so indices must be unique |
| grad_indices = grad._indices() |
| grad_values = grad._values() |
| size = grad.size() |
| |
| state_sum.add_(_make_sparse(grad, grad_indices, grad_values.pow(2))) |
| std = state_sum.sparse_mask(grad) |
| std_values = std._values().sqrt_().add_(eps) |
| param.add_(_make_sparse(grad, grad_indices, grad_values / std_values), alpha=-clr) |
| else: |
| is_complex = torch.is_complex(param) |
| if is_complex: |
| grad = torch.view_as_real(grad) |
| state_sum = torch.view_as_real(state_sum) |
| param = torch.view_as_real(param) |
| state_sum.addcmul_(grad, grad, value=1) |
| std = state_sum.sqrt().add_(eps) |
| param.addcdiv_(grad, std, value=-clr) |
| if is_complex: |
| param = torch.view_as_complex(param) |
| state_sum = torch.view_as_complex(state_sum) |
| |
| |
| def _multi_tensor_adagrad(params: List[Tensor], |
| grads: List[Tensor], |
| state_sums: List[Tensor], |
| state_steps: List[Tensor], |
| *, |
| lr: float, |
| weight_decay: float, |
| lr_decay: float, |
| eps: float, |
| has_sparse_grad: bool): |
| |
| # Foreach functions will throw errors if given empty lists |
| if len(params) == 0: |
| return |
| |
| if has_sparse_grad is None: |
| has_sparse_grad = any([grad.is_sparse for grad in grads]) |
| |
| if has_sparse_grad: |
| return _single_tensor_adagrad(params, |
| grads, |
| state_sums, |
| state_steps, |
| lr=lr, |
| weight_decay=weight_decay, |
| lr_decay=lr_decay, |
| eps=eps, |
| has_sparse_grad=has_sparse_grad) |
| |
| # Update steps |
| torch._foreach_add_(state_steps, 1) |
| |
| if weight_decay != 0: |
| torch._foreach_add_(grads, params, alpha=weight_decay) |
| |
| minus_clr = [-lr / (1 + (step - 1) * lr_decay) for step in state_steps] |
| |
| grads = [torch.view_as_real(x) if torch.is_complex(x) else x for x in grads] |
| state_sums = [torch.view_as_real(x) if torch.is_complex(x) else x for x in state_sums] |
| torch._foreach_addcmul_(state_sums, grads, grads, value=1) |
| std = torch._foreach_add(torch._foreach_sqrt(state_sums), eps) |
| toAdd = torch._foreach_div(torch._foreach_mul(grads, minus_clr), std) |
| toAdd = [torch.view_as_complex(x) if torch.is_complex(params[i]) else x for i, x in enumerate(toAdd)] |
| torch._foreach_add_(params, toAdd) |
| state_sums = [torch.view_as_complex(x) if torch.is_complex(params[i]) else x for i, x in enumerate(state_sums)] |