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# Copyright (c) Microsoft Corporation. | |
# Licensed under the MIT license. | |
import math | |
import torch | |
from torch.optim.optimizer import Optimizer, required | |
class RAdam(Optimizer): | |
""" | |
@article{liu2019radam, | |
title={On the Variance of the Adaptive Learning Rate and Beyond}, | |
author={Liu, Liyuan and Jiang, Haoming and He, Pengcheng and Chen, Weizhu and Liu, Xiaodong and Gao, Jianfeng and Han, Jiawei}, | |
journal={arXiv preprint arXiv:1908.03265}, | |
year={2019} | |
} | |
""" | |
def __init__(self, params, lr=1e-3, betas=(0.9, 0.999), eps=1e-8, weight_decay=0): | |
defaults = dict(lr=lr, betas=betas, eps=eps, weight_decay=weight_decay) | |
self.buffer = [[None, None, None] for ind in range(10)] | |
super(RAdam, self).__init__(params, defaults) | |
def __setstate__(self, state): | |
super(RAdam, self).__setstate__(state) | |
def step(self, closure=None): | |
loss = None | |
if closure is not None: | |
loss = closure() | |
for group in self.param_groups: | |
for p in group["params"]: | |
if p.grad is None: | |
continue | |
grad = p.grad.data.float() | |
if grad.is_sparse: | |
raise RuntimeError("RAdam does not support sparse gradients") | |
p_data_fp32 = p.data.float() | |
state = self.state[p] | |
if len(state) == 0: | |
state["step"] = 0 | |
state["exp_avg"] = torch.zeros_like(p_data_fp32) | |
state["exp_avg_sq"] = torch.zeros_like(p_data_fp32) | |
else: | |
state["exp_avg"] = state["exp_avg"].type_as(p_data_fp32) | |
state["exp_avg_sq"] = state["exp_avg_sq"].type_as(p_data_fp32) | |
exp_avg, exp_avg_sq = state["exp_avg"], state["exp_avg_sq"] | |
beta1, beta2 = group["betas"] | |
exp_avg_sq.mul_(beta2).addcmul_(1 - beta2, grad, grad) | |
exp_avg.mul_(beta1).add_(1 - beta1, grad) | |
state["step"] += 1 | |
buffered = self.buffer[int(state["step"] % 10)] | |
if state["step"] == buffered[0]: | |
N_sma, step_size = buffered[1], buffered[2] | |
else: | |
buffered[0] = state["step"] | |
beta2_t = beta2 ** state["step"] | |
N_sma_max = 2 / (1 - beta2) - 1 | |
N_sma = N_sma_max - 2 * state["step"] * beta2_t / (1 - beta2_t) | |
buffered[1] = N_sma | |
# more conservative since it's an approximated value | |
if N_sma >= 5: | |
step_size = ( | |
group["lr"] | |
* math.sqrt( | |
(1 - beta2_t) | |
* (N_sma - 4) | |
/ (N_sma_max - 4) | |
* (N_sma - 2) | |
/ N_sma | |
* N_sma_max | |
/ (N_sma_max - 2) | |
) | |
/ (1 - beta1 ** state["step"]) | |
) | |
else: | |
step_size = group["lr"] / (1 - beta1 ** state["step"]) | |
buffered[2] = step_size | |
if group["weight_decay"] != 0: | |
p_data_fp32.add_(-group["weight_decay"] * group["lr"], p_data_fp32) | |
# more conservative since it's an approximated value | |
if N_sma >= 5: | |
denom = exp_avg_sq.sqrt().add_(group["eps"]) | |
p_data_fp32.addcdiv_(-step_size, exp_avg, denom) | |
else: | |
p_data_fp32.add_(-step_size, exp_avg) | |
p.data.copy_(p_data_fp32) | |
return loss | |
class PlainRAdam(Optimizer): | |
def __init__(self, params, lr=1e-3, betas=(0.9, 0.999), eps=1e-8, weight_decay=0): | |
defaults = dict(lr=lr, betas=betas, eps=eps, weight_decay=weight_decay) | |
super(PlainRAdam, self).__init__(params, defaults) | |
def __setstate__(self, state): | |
super(PlainRAdam, self).__setstate__(state) | |
def step(self, closure=None): | |
loss = None | |
if closure is not None: | |
loss = closure() | |
for group in self.param_groups: | |
for p in group["params"]: | |
if p.grad is None: | |
continue | |
grad = p.grad.data.float() | |
if grad.is_sparse: | |
raise RuntimeError("RAdam does not support sparse gradients") | |
p_data_fp32 = p.data.float() | |
state = self.state[p] | |
if len(state) == 0: | |
state["step"] = 0 | |
state["exp_avg"] = torch.zeros_like(p_data_fp32) | |
state["exp_avg_sq"] = torch.zeros_like(p_data_fp32) | |
else: | |
state["exp_avg"] = state["exp_avg"].type_as(p_data_fp32) | |
state["exp_avg_sq"] = state["exp_avg_sq"].type_as(p_data_fp32) | |
exp_avg, exp_avg_sq = state["exp_avg"], state["exp_avg_sq"] | |
beta1, beta2 = group["betas"] | |
exp_avg_sq.mul_(beta2).addcmul_(1 - beta2, grad, grad) | |
exp_avg.mul_(beta1).add_(1 - beta1, grad) | |
state["step"] += 1 | |
beta2_t = beta2 ** state["step"] | |
N_sma_max = 2 / (1 - beta2) - 1 | |
N_sma = N_sma_max - 2 * state["step"] * beta2_t / (1 - beta2_t) | |
if group["weight_decay"] != 0: | |
p_data_fp32.add_(-group["weight_decay"] * group["lr"], p_data_fp32) | |
# more conservative since it's an approximated value | |
if N_sma >= 5: | |
step_size = ( | |
group["lr"] | |
* math.sqrt( | |
(1 - beta2_t) | |
* (N_sma - 4) | |
/ (N_sma_max - 4) | |
* (N_sma - 2) | |
/ N_sma | |
* N_sma_max | |
/ (N_sma_max - 2) | |
) | |
/ (1 - beta1 ** state["step"]) | |
) | |
denom = exp_avg_sq.sqrt().add_(group["eps"]) | |
p_data_fp32.addcdiv_(-step_size, exp_avg, denom) | |
else: | |
step_size = group["lr"] / (1 - beta1 ** state["step"]) | |
p_data_fp32.add_(-step_size, exp_avg) | |
p.data.copy_(p_data_fp32) | |
return loss | |
class AdamW(Optimizer): | |
def __init__( | |
self, params, lr=1e-3, betas=(0.9, 0.999), eps=1e-8, weight_decay=0, warmup=0 | |
): | |
defaults = dict( | |
lr=lr, betas=betas, eps=eps, weight_decay=weight_decay, warmup=warmup | |
) | |
super(AdamW, self).__init__(params, defaults) | |
def __setstate__(self, state): | |
super(AdamW, self).__setstate__(state) | |
def step(self, closure=None): | |
loss = None | |
if closure is not None: | |
loss = closure() | |
for group in self.param_groups: | |
for p in group["params"]: | |
if p.grad is None: | |
continue | |
grad = p.grad.data.float() | |
if grad.is_sparse: | |
raise RuntimeError( | |
"Adam does not support sparse gradients, please consider SparseAdam instead" | |
) | |
p_data_fp32 = p.data.float() | |
state = self.state[p] | |
if len(state) == 0: | |
state["step"] = 0 | |
state["exp_avg"] = torch.zeros_like(p_data_fp32) | |
state["exp_avg_sq"] = torch.zeros_like(p_data_fp32) | |
else: | |
state["exp_avg"] = state["exp_avg"].type_as(p_data_fp32) | |
state["exp_avg_sq"] = state["exp_avg_sq"].type_as(p_data_fp32) | |
exp_avg, exp_avg_sq = state["exp_avg"], state["exp_avg_sq"] | |
beta1, beta2 = group["betas"] | |
state["step"] += 1 | |
exp_avg_sq.mul_(beta2).addcmul_(1 - beta2, grad, grad) | |
exp_avg.mul_(beta1).add_(1 - beta1, grad) | |
denom = exp_avg_sq.sqrt().add_(group["eps"]) | |
bias_correction1 = 1 - beta1 ** state["step"] | |
bias_correction2 = 1 - beta2 ** state["step"] | |
if group["warmup"] > state["step"]: | |
scheduled_lr = 1e-8 + state["step"] * group["lr"] / group["warmup"] | |
else: | |
scheduled_lr = group["lr"] | |
step_size = group["lr"] * math.sqrt(bias_correction2) / bias_correction1 | |
if group["weight_decay"] != 0: | |
p_data_fp32.add_(-group["weight_decay"] * scheduled_lr, p_data_fp32) | |
p_data_fp32.addcdiv_(-step_size, exp_avg, denom) | |
p.data.copy_(p_data_fp32) | |
return loss | |