class Solver(object):
def __init__(self, config, data_loader):
self.generator = None
self.discriminator = None
self.g_optimizer = None
self.d_optimizer = None
self.g_conv_dim = config.g_conv_dim
self.d_conv_dim = config.d_conv_dim
self.z_dim = config.z_dim
self.beta1 = config.beta1
self.beta2 = config.beta2
self.image_size = config.image_size
self.data_loader = data_loader
self.num_epochs = config.num_epochs
self.batch_size = config.batch_size
self.sample_size = config.sample_size
self.lr = config.lr
self.log_step = config.log_step
self.sample_step = config.sample_step
self.sample_path = config.sample_path
self.model_path = config.model_path
self.epoch = config.epoch
self.build_model()
self.plotter = Plotter()
def build_model(self):
"""Build generator and discriminator."""
self.generator = Generator(z_dim=self.z_dim)
print(count_parameters(self.generator))
self.discriminator = Discriminator()
print(count_parameters(self.discriminator))
self.g_optimizer = optim.Adam(self.generator.parameters(),
self.lr, (self.beta1, self.beta2))
self.d_optimizer = optim.Adam(self.discriminator.parameters(),
self.lr*1, (self.beta1, self.beta2))
if self.epoch:
g_path = os.path.join(self.model_path, 'generator-%d.pkl' % self.epoch)
d_path = os.path.join(self.model_path, 'discriminator-%d.pkl' % self.epoch)
g_optim_path = os.path.join(self.model_path, 'gen-optim-%d.pkl' % self.epoch)
d_optim_path = os.path.join(self.model_path, 'dis-optim-%d.pkl' % self.epoch)
self.generator.load_state_dict(torch.load(g_path))
self.discriminator.load_state_dict(torch.load(d_path))
self.g_optimizer.load_state_dict(torch.load(g_optim_path))
self.d_optimizer.load_state_dict(torch.load(d_optim_path))
if torch.cuda.is_available():
self.generator.cuda()
self.discriminator.cuda()
def to_variable(self, x):
"""Convert tensor to variable."""
if torch.cuda.is_available():
x = x.cuda()
return Variable(x)
def to_data(self, x):
"""Convert variable to tensor."""
if torch.cuda.is_available():
x = x.cpu()
return x.data
def reset_grad(self):
"""Zero the gradient buffers."""
self.discriminator.zero_grad()
self.generator.zero_grad()
def denorm(self, x):
"""Convert range (-1, 1) to (0, 1)"""
out = (x + 1) / 2
return out.clamp(0, 1)
def train(self):
"""Train generator and discriminator."""
fixed_noise = self.to_variable(torch.randn(self.batch_size, self.z_dim))
total_step = len(self.data_loader)
for epoch in range(self.epoch, self.epoch + self.num_epochs) if self.epoch else range(self.num_epochs):
for i, images in enumerate(self.data_loader):
if len(images) != self.batch_size:
continue
# self.plotter.draw_kernels(self.discriminator)
for p in self.discriminator.parameters():
p.requires_grad = True
#===================== Train D =====================#
images = self.to_variable(images)
images.retain_grad()
batch_size = images.size(0)
noise = self.to_variable(torch.randn(batch_size, self.z_dim))
# Train D to recognize real images as real.
outputs = self.discriminator(images)
real_loss = torch.mean((outputs - 1) ** 2) # L2 loss instead of Binary cross entropy loss (this is optional for stable training)
# real_loss = torch.mean(outputs - 1)
# Train D to recognize fake images as fake.
fake_images = self.generator(noise)
fake_images.retain_grad()
outputs = self.discriminator(fake_images)
fake_loss = torch.mean(outputs ** 2)
# fake_loss = torch.mean(outputs)
# gradient penalty
gp_loss = calc_gradient_penalty(self.discriminator, images, fake_images)
# Backprop + optimize
d_loss = fake_loss + real_loss + gp_loss
self.reset_grad()
d_loss.backward()
self.d_optimizer.step()
if i % 10 == 0:
self.plotter.draw_activations(fake_images.grad[0], original=fake_images[0])
g_losses = []
for p in self.discriminator.parameters():
p.requires_grad = False
#===================== Train G =====================#
for g_batch in range(5):
noise = self.to_variable(torch.randn(batch_size, self.z_dim))
# Train G so that D recognizes G(z) as real.
fake_images = self.generator(noise)
outputs = self.discriminator(fake_images)
g_loss = torch.mean((outputs - 1) ** 2)
# g_loss = -torch.mean(outputs)
# Backprop + optimize
self.reset_grad()
g_loss.backward()
# if g_loss.item() < 0.5 * d_loss.item():
# break
self.g_optimizer.step()
g_losses.append("%.3f"%g_loss.clone().item())
# print the log info
if (i+1) % self.log_step == 0:
print('Epoch [%d/%d], Step[%d/%d], d_real_loss: %.4f, '
'd_fake_loss: %.4f, gp_loss: %s, g_loss: %s'
%(epoch+1, self.num_epochs, i+1, total_step,
real_loss.item(), fake_loss.item(), gp_loss.item(), ", ".join(g_losses)))
# save the sampled images
# print((i+1)%self.sample_step)
if (i) % self.sample_step == 0:
print("saving samples")
fake_images = self.generator(fixed_noise)
if not os.path.exists(self.sample_path):
os.makedirs(self.sample_path)
torchvision.utils.save_image(self.denorm(fake_images.data),
os.path.join(self.sample_path,
'fake_samples-%d-%d.png' %(epoch+1, i+1)))
# save the model parameters for each epoch
if epoch % 5 == 0:
if not os.path.exists(self.model_path):
os.mkdir(self.model_path)
g_path = os.path.join(self.model_path, 'generator-%d.pkl' %(epoch+1))
d_path = os.path.join(self.model_path, 'discriminator-%d.pkl' %(epoch+1))
g_optim_path = os.path.join(self.model_path, 'gen-optim-%d.pkl' % (epoch + 1))
d_optim_path = os.path.join(self.model_path, 'dis-optim-%d.pkl' % (epoch + 1))
torch.save(self.generator.state_dict(), g_path)
torch.save(self.discriminator.state_dict(), d_path)
torch.save(self.g_optimizer.state_dict(), g_optim_path)
torch.save(self.d_optimizer.state_dict(), d_optim_path)
def sample(self):
# Load trained parameters
g_path = os.path.join(self.model_path, 'generator-%d.pkl' % self.num_epochs)
d_path = os.path.join(self.model_path, 'discriminator-%d.pkl' % self.num_epochs)
self.generator.load_state_dict(torch.load(g_path))
self.discriminator.load_state_dict(torch.load(d_path))
self.generator.eval()
self.discriminator.eval()
# Sample the images
noise = self.to_variable(torch.randn(self.sample_size, self.z_dim))
fake_images = self.generator(noise)
sample_path = os.path.join(self.sample_path, 'fake_samples-final.png')
torchvision.utils.save_image(self.denorm(fake_images.data), sample_path, nrow=12)
print("Saved sampled images to '%s'" %sample_path)
torch.manual_seed(opt.random_seed)
cuda = True if torch.cuda.is_available() and opt.cuda else False
Tensor = torch.cuda.FloatTensor if torch.cuda.is_available() and opt.cuda else torch.FloatTensor
# Loss weight for gradient penalty
lambda_gp = opt.lambda_gp
# Initialize generator and discriminator
generator = Generator(opt.latent_dim, 2)
discriminator = Discriminator(2)
gaussian = GaussianMixture(opt.grid_side_size)
train_data = gaussian.sample(opt.batch_size * opt.target_factor if opt.learning_type == 'smallgan' else opt.batch_size)
if cuda:
generator.cuda()
discriminator.cuda()
prior_batch_size = opt.batch_size * opt.prior_factor if opt.learning_type == 'smallgan' else opt.batch_size
# Valid dataset
valid_samples = np.random.uniform(-1, 1, (opt.valid_size, opt.latent_dim))
valid_dataloader = torch.utils.data.DataLoader(
valid_samples,
batch_size=opt.valid_batch_size,
shuffle=False,
num_workers=opt.n_cpu,
)
# Optimizers
optimizer_G = torch.optim.Adam(generator.parameters(), lr=opt.lr, betas=(opt.b1, opt.b2))
optimizer_D = torch.optim.Adam(discriminator.parameters(), lr=opt.lr, betas=(opt.b1, opt.b2))