A PyTorch implementation for paper Unsupervised Domain Adaptation by Backpropagation
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"""Train dann."""
import torch
import torch.nn as nn
import torch.optim as optim
import params
from utils import make_variable, save_model
import numpy as np
from core.test import eval
import torch.backends.cudnn as cudnn
cudnn.benchmark = True
def train_dann(dann, src_data_loader, tgt_data_loader, tgt_data_loader_eval):
"""Train dann."""
####################
# 1. setup network #
####################
# set train state for Dropout and BN layers
dann.train()
# setup criterion and optimizer
optimizer = optim.Adam(dann.parameters(), lr=params.lr)
criterion = nn.NLLLoss()
for p in dann.parameters():
p.requires_grad = True
####################
# 2. train network #
####################
# prepare domain label
label_src = make_variable(torch.zeros(params.batch_size).long()) # source 0
label_tgt = make_variable(torch.ones(params.batch_size).long()) # target 1
for epoch in range(params.num_epochs):
# zip source and target data pair
len_dataloader = min(len(src_data_loader), len(tgt_data_loader))
data_zip = enumerate(zip(src_data_loader, tgt_data_loader))
for step, ((images_src, class_src), (images_tgt, _)) in data_zip:
p = float(step + epoch * len_dataloader) / params.num_epochs / len_dataloader
alpha = 2. / (1. + np.exp(-10 * p)) - 1
# make images variable
class_src = make_variable(class_src)
images_src = make_variable(images_src)
images_tgt = make_variable(images_tgt)
# zero gradients for optimizer
optimizer.zero_grad()
# train on source domain
src_class_output, src_domain_output = dann(input_data=images_src, alpha=alpha)
src_loss_class = criterion(src_class_output, class_src)
src_loss_domain = criterion(src_domain_output, label_src)
# train on target domain
_, tgt_domain_output = dann(input_data=images_tgt, alpha=alpha)
tgt_loss_domain = criterion(tgt_domain_output, label_tgt)
loss = src_loss_class + src_loss_domain + tgt_loss_domain
# optimize dann
loss.backward()
optimizer.step()
# print step info
if ((step + 1) % params.log_step == 0):
print("Epoch [{}/{}] Step [{}/{}]: src_loss_class={}, src_loss_domain={}, tgt_loss_domain={}, loss={}"
.format(epoch + 1,
params.num_epochs,
step + 1,
len_dataloader,
src_loss_class.data[0],
src_loss_domain.data[0],
tgt_loss_domain.data[0],
loss.data[0]))
# eval model on test set
if ((epoch + 1) % params.eval_step == 0):
eval(dann, tgt_data_loader_eval)
dann.train()
# save model parameters
if ((epoch + 1) % params.save_step == 0):
save_model(dann, params.src_dataset + '-' + params.tgt_dataset + "-dann-{}.pt".format(epoch + 1))
# save final model
save_model(dann, params.src_dataset + '-' + params.tgt_dataset + "-dann-final.pt")
return dann