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util.py
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util.py
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from __future__ import print_function
import math
import numpy as np
import torch
import torch.optim as optim
class TwoCropTransform:
"""Create two crops of the same image"""
def __init__(self, transform):
self.transform = transform
def __call__(self, x):
return [self.transform(x), self.transform(x)]
class AverageMeter(object):
"""Computes and stores the average and current value"""
def __init__(self):
self.reset()
def reset(self):
self.val = 0
self.avg = 0
self.sum = 0
self.count = 0
def update(self, val, n=1):
self.val = val
self.sum += val * n
self.count += n
self.avg = self.sum / self.count
def accuracy(output, target, topk=(1,)):
"""Computes the accuracy over the k top predictions for the specified values of k"""
with torch.no_grad():
maxk = max(topk)
batch_size = target.size(0)
_, pred = output.topk(maxk, 1, True, True)
pred = pred.t()
correct = pred.eq(target.view(1, -1).expand_as(pred))
res = []
for k in topk:
correct_k = correct[:k].view(-1).float().sum(0, keepdim=True)
res.append(correct_k.mul_(100.0 / batch_size))
return res
def adjust_learning_rate(args, optimizer, epoch):
lr = args.learning_rate
if args.cosine:
eta_min = lr * (args.lr_decay_rate ** 3)
lr = eta_min + (lr - eta_min) * (
1 + math.cos(math.pi * epoch / args.epochs)) / 2
else:
steps = np.sum(epoch > np.asarray(args.lr_decay_epochs))
if steps > 0:
lr = lr * (args.lr_decay_rate ** steps)
for param_group in optimizer.param_groups:
param_group['lr'] = lr
def warmup_learning_rate(args, epoch, batch_id, total_batches, optimizer):
if args.warm and epoch <= args.warm_epochs:
p = (batch_id + (epoch - 1) * total_batches) / \
(args.warm_epochs * total_batches)
lr = args.warmup_from + p * (args.warmup_to - args.warmup_from)
for param_group in optimizer.param_groups:
param_group['lr'] = lr
def set_optimizer(opt, model):
optimizer = optim.SGD(model.parameters(),
lr=opt.learning_rate,
momentum=opt.momentum,
weight_decay=opt.weight_decay)
return optimizer
def save_model(model, optimizer, opt, epoch, save_file):
print('==> Saving...')
state = {
'opt': opt,
'model': model.state_dict(),
'optimizer': optimizer.state_dict(),
'epoch': epoch,
}
torch.save(state, save_file)
del state