205 lines
7.8 KiB
Python
205 lines
7.8 KiB
Python
#####################################################
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# Copyright (c) Xuanyi Dong [GitHub D-X-Y], 2019.01 #
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#####################################################
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import math, torch
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import torch.nn as nn
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from bisect import bisect_right
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from torch.optim import Optimizer
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class _LRScheduler(object):
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def __init__(self, optimizer, warmup_epochs, epochs):
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if not isinstance(optimizer, Optimizer):
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raise TypeError('{:} is not an Optimizer'.format(type(optimizer).__name__))
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self.optimizer = optimizer
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for group in optimizer.param_groups:
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group.setdefault('initial_lr', group['lr'])
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self.base_lrs = list(map(lambda group: group['initial_lr'], optimizer.param_groups))
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self.max_epochs = epochs
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self.warmup_epochs = warmup_epochs
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self.current_epoch = 0
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self.current_iter = 0
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def extra_repr(self):
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return ''
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def __repr__(self):
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return ('{name}(warmup={warmup_epochs}, max-epoch={max_epochs}, current::epoch={current_epoch}, iter={current_iter:.2f}'.format(name=self.__class__.__name__, **self.__dict__)
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+ ', {:})'.format(self.extra_repr()))
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def state_dict(self):
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return {key: value for key, value in self.__dict__.items() if key != 'optimizer'}
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def load_state_dict(self, state_dict):
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self.__dict__.update(state_dict)
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def get_lr(self):
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raise NotImplementedError
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def get_min_info(self):
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lrs = self.get_lr()
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return '#LR=[{:.6f}~{:.6f}] epoch={:03d}, iter={:4.2f}#'.format(min(lrs), max(lrs), self.current_epoch, self.current_iter)
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def get_min_lr(self):
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return min( self.get_lr() )
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def update(self, cur_epoch, cur_iter):
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if cur_epoch is not None:
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assert isinstance(cur_epoch, int) and cur_epoch>=0, 'invalid cur-epoch : {:}'.format(cur_epoch)
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self.current_epoch = cur_epoch
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if cur_iter is not None:
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assert isinstance(cur_iter, float) and cur_iter>=0, 'invalid cur-iter : {:}'.format(cur_iter)
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self.current_iter = cur_iter
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for param_group, lr in zip(self.optimizer.param_groups, self.get_lr()):
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param_group['lr'] = lr
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class CosineAnnealingLR(_LRScheduler):
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def __init__(self, optimizer, warmup_epochs, epochs, T_max, eta_min):
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self.T_max = T_max
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self.eta_min = eta_min
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super(CosineAnnealingLR, self).__init__(optimizer, warmup_epochs, epochs)
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def extra_repr(self):
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return 'type={:}, T-max={:}, eta-min={:}'.format('cosine', self.T_max, self.eta_min)
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def get_lr(self):
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lrs = []
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for base_lr in self.base_lrs:
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if self.current_epoch >= self.warmup_epochs and self.current_epoch < self.max_epochs:
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last_epoch = self.current_epoch - self.warmup_epochs
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#if last_epoch < self.T_max:
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#if last_epoch < self.max_epochs:
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lr = self.eta_min + (base_lr - self.eta_min) * (1 + math.cos(math.pi * last_epoch / self.T_max)) / 2
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#else:
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# lr = self.eta_min + (base_lr - self.eta_min) * (1 + math.cos(math.pi * (self.T_max-1.0) / self.T_max)) / 2
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elif self.current_epoch >= self.max_epochs:
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lr = self.eta_min
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else:
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lr = (self.current_epoch / self.warmup_epochs + self.current_iter / self.warmup_epochs) * base_lr
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lrs.append( lr )
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return lrs
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class MultiStepLR(_LRScheduler):
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def __init__(self, optimizer, warmup_epochs, epochs, milestones, gammas):
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assert len(milestones) == len(gammas), 'invalid {:} vs {:}'.format(len(milestones), len(gammas))
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self.milestones = milestones
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self.gammas = gammas
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super(MultiStepLR, self).__init__(optimizer, warmup_epochs, epochs)
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def extra_repr(self):
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return 'type={:}, milestones={:}, gammas={:}, base-lrs={:}'.format('multistep', self.milestones, self.gammas, self.base_lrs)
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def get_lr(self):
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lrs = []
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for base_lr in self.base_lrs:
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if self.current_epoch >= self.warmup_epochs:
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last_epoch = self.current_epoch - self.warmup_epochs
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idx = bisect_right(self.milestones, last_epoch)
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lr = base_lr
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for x in self.gammas[:idx]: lr *= x
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else:
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lr = (self.current_epoch / self.warmup_epochs + self.current_iter / self.warmup_epochs) * base_lr
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lrs.append( lr )
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return lrs
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class ExponentialLR(_LRScheduler):
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def __init__(self, optimizer, warmup_epochs, epochs, gamma):
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self.gamma = gamma
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super(ExponentialLR, self).__init__(optimizer, warmup_epochs, epochs)
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def extra_repr(self):
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return 'type={:}, gamma={:}, base-lrs={:}'.format('exponential', self.gamma, self.base_lrs)
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def get_lr(self):
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lrs = []
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for base_lr in self.base_lrs:
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if self.current_epoch >= self.warmup_epochs:
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last_epoch = self.current_epoch - self.warmup_epochs
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assert last_epoch >= 0, 'invalid last_epoch : {:}'.format(last_epoch)
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lr = base_lr * (self.gamma ** last_epoch)
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else:
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lr = (self.current_epoch / self.warmup_epochs + self.current_iter / self.warmup_epochs) * base_lr
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lrs.append( lr )
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return lrs
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class LinearLR(_LRScheduler):
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def __init__(self, optimizer, warmup_epochs, epochs, max_LR, min_LR):
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self.max_LR = max_LR
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self.min_LR = min_LR
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super(LinearLR, self).__init__(optimizer, warmup_epochs, epochs)
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def extra_repr(self):
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return 'type={:}, max_LR={:}, min_LR={:}, base-lrs={:}'.format('LinearLR', self.max_LR, self.min_LR, self.base_lrs)
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def get_lr(self):
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lrs = []
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for base_lr in self.base_lrs:
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if self.current_epoch >= self.warmup_epochs:
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last_epoch = self.current_epoch - self.warmup_epochs
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assert last_epoch >= 0, 'invalid last_epoch : {:}'.format(last_epoch)
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ratio = (self.max_LR - self.min_LR) * last_epoch / self.max_epochs / self.max_LR
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lr = base_lr * (1-ratio)
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else:
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lr = (self.current_epoch / self.warmup_epochs + self.current_iter / self.warmup_epochs) * base_lr
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lrs.append( lr )
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return lrs
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class CrossEntropyLabelSmooth(nn.Module):
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def __init__(self, num_classes, epsilon):
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super(CrossEntropyLabelSmooth, self).__init__()
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self.num_classes = num_classes
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self.epsilon = epsilon
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self.logsoftmax = nn.LogSoftmax(dim=1)
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def forward(self, inputs, targets):
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log_probs = self.logsoftmax(inputs)
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targets = torch.zeros_like(log_probs).scatter_(1, targets.unsqueeze(1), 1)
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targets = (1 - self.epsilon) * targets + self.epsilon / self.num_classes
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loss = (-targets * log_probs).mean(0).sum()
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return loss
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def get_optim_scheduler(parameters, config):
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assert hasattr(config, 'optim') and hasattr(config, 'scheduler') and hasattr(config, 'criterion'), 'config must have optim / scheduler / criterion keys instead of {:}'.format(config)
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if config.optim == 'SGD':
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optim = torch.optim.SGD(parameters, config.LR, momentum=config.momentum, weight_decay=config.decay, nesterov=config.nesterov)
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elif config.optim == 'RMSprop':
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optim = torch.optim.RMSprop(parameters, config.LR, momentum=config.momentum, weight_decay=config.decay)
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else:
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raise ValueError('invalid optim : {:}'.format(config.optim))
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if config.scheduler == 'cos':
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T_max = getattr(config, 'T_max', config.epochs)
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scheduler = CosineAnnealingLR(optim, config.warmup, config.epochs, T_max, config.eta_min)
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elif config.scheduler == 'multistep':
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scheduler = MultiStepLR(optim, config.warmup, config.epochs, config.milestones, config.gammas)
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elif config.scheduler == 'exponential':
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scheduler = ExponentialLR(optim, config.warmup, config.epochs, config.gamma)
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elif config.scheduler == 'linear':
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scheduler = LinearLR(optim, config.warmup, config.epochs, config.LR, config.LR_min)
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else:
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raise ValueError('invalid scheduler : {:}'.format(config.scheduler))
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if config.criterion == 'Softmax':
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criterion = torch.nn.CrossEntropyLoss()
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elif config.criterion == 'SmoothSoftmax':
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criterion = CrossEntropyLabelSmooth(config.class_num, config.label_smooth)
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else:
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raise ValueError('invalid criterion : {:}'.format(config.criterion))
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return optim, scheduler, criterion
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