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import os
from importlib import import_module
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
def sequence_loss(sr, hr, loss_func, gamma=0.8, max_val=None):
""" Loss function defined over sequence of flow predictions """
n_recurrence = len(sr)
total_loss = 0.0
buffer=[0.0]*n_recurrence
# exlude invalid pixels and extremely large diplacements
for i in range(n_recurrence):
i_weight = gamma**(n_recurrence - i - 1)
i_loss = loss_func(sr[i],hr)
buffer[i]=i_loss.item()
# total_loss += i_weight * (valid[:, None] * i_loss).mean()
total_loss += i_weight * (i_loss)
return total_loss,buffer
class Loss(nn.modules.loss._Loss):
def __init__(self, args, ckp):
super(Loss, self).__init__()
print('Preparing loss function:')
self.buffer=[0.0]*args.recurrence
self.n_GPUs = args.n_GPUs
self.loss = []
self.decay_gamma=args.decay_gamma
self.loss_module = nn.ModuleList()
for loss in args.loss.split('+'):
weight, loss_type = loss.split('*')
if loss_type == 'MSE':
loss_function = nn.MSELoss()
elif loss_type == 'L1':
loss_function = nn.L1Loss()
elif loss_type.find('VGG') >= 0:
module = import_module('loss.vgg')
loss_function = getattr(module, 'VGG')(
loss_type[3:],
rgb_range=args.rgb_range
)
elif loss_type.find('GAN') >= 0:
module = import_module('loss.adversarial')
loss_function = getattr(module, 'Adversarial')(
args,
loss_type
)
self.loss.append({
'type': loss_type,
'weight': float(weight),
'function': loss_function}
)
if loss_type.find('GAN') >= 0:
self.loss.append({'type': 'DIS', 'weight': 1, 'function': None})
if len(self.loss) > 1:
self.loss.append({'type': 'Total', 'weight': 0, 'function': None})
for l in self.loss:
if l['function'] is not None:
print('{:.3f} * {}'.format(l['weight'], l['type']))
# self.loss_module.append(l['function'])
self.log = torch.Tensor()
device = torch.device('cpu' if args.cpu else 'cuda')
self.loss_module.to(device)
if args.precision == 'half': self.loss_module.half()
if not args.cpu and args.n_GPUs > 1:
self.loss_module = nn.DataParallel(
self.loss_module, range(args.n_GPUs)
)
if args.load != '': self.load(ckp.dir, cpu=args.cpu)
def forward(self, sr, hr):
losses = []
for i, l in enumerate(self.loss):
if l['function'] is not None:
if isinstance(sr,list):
# weights=[0.32,0.08,0.02,0.01,0.005]
# weights=weights[::-1]
# weights=[0.01,0.02,0.08,0.32]
# self.buffer=[]
effective_loss,buffer_lst=sequence_loss(sr,hr,l['function'],gamma=self.decay_gamma)
# for k in range(len(sr)):
# loss=l['function'](sr[k], hr)
# self.buffer.append(loss.item())
# effective_loss=loss*weights[k]*l['weight']
losses.append(effective_loss)
self.buffer=buffer_lst
self.log[-1, i] += effective_loss.item()
else:
loss = l['function'](sr, hr)
effective_loss = l['weight'] * loss
losses.append(effective_loss)
self.buffer[0]=effective_loss.item()
self.log[-1, i] += effective_loss.item()
elif l['type'] == 'DIS':
self.log[-1, i] += self.loss[i - 1]['function'].loss
loss_sum = sum(losses)
if len(self.loss) > 1:
self.log[-1, -1] += loss_sum.item()
return loss_sum
def step(self):
for l in self.get_loss_module():
if hasattr(l, 'scheduler'):
l.scheduler.step()
def start_log(self):
self.log = torch.cat((self.log, torch.zeros(1, len(self.loss))))
def end_log(self, n_batches):
self.log[-1].div_(n_batches)
def display_loss(self, batch):
n_samples = batch + 1
log = []
for l, c in zip(self.loss, self.log[-1]):
log.append('[{}: {:.4f}]'.format(l['type'], c / n_samples))
return ''.join(log)
def plot_loss(self, apath, epoch):
axis = np.linspace(1, epoch, epoch)
for i, l in enumerate(self.loss):
label = '{} Loss'.format(l['type'])
fig = plt.figure()
plt.title(label)
plt.plot(axis, self.log[:, i].numpy(), label=label)
plt.legend()
plt.xlabel('Epochs')
plt.ylabel('Loss')
plt.grid(True)
plt.savefig(os.path.join(apath, 'loss_{}.pdf'.format(l['type'])))
plt.close(fig)
def get_loss_module(self):
if self.n_GPUs == 1:
return self.loss_module
else:
return self.loss_module.module
def save(self, apath):
torch.save(self.state_dict(), os.path.join(apath, 'loss.pt'))
torch.save(self.log, os.path.join(apath, 'loss_log.pt'))
def load(self, apath, cpu=False):
if cpu:
kwargs = {'map_location': lambda storage, loc: storage}
else:
kwargs = {}
self.load_state_dict(torch.load(
os.path.join(apath, 'loss.pt'),
**kwargs
))
self.log = torch.load(os.path.join(apath, 'loss_log.pt'))
for l in self.get_loss_module():
if hasattr(l, 'scheduler'):
for _ in range(len(self.log)): l.scheduler.step()
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