def main():
generator = nn.Sequential(
# We want to generate 128 coefficients to reshape into a 7x7x128 map
nn.Linear(128, 128 * 7 * 7),
nn.LeakyReLU(0.2, inplace=True),
Lambda(lambda x: x.view(x.size(0), 128, 7, 7)),
nn.ConvTranspose2d(128, 128, (4, 4), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.ConvTranspose2d(128, 128, (4, 4), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(128, 1, (7, 7), padding=3),
nn.Sigmoid(),
)
discriminator = nn.Sequential(
nn.Conv2d(1, 64, (3, 3), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(64, 128, (3, 3), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
GlobalMaxPool2d(),
Flatten(),
nn.Linear(128, 1),
)
model = {"generator": generator, "discriminator": discriminator}
optimizer = {
"generator": torch.optim.Adam(
generator.parameters(), lr=0.0003, betas=(0.5, 0.999)
),
"discriminator": torch.optim.Adam(
discriminator.parameters(), lr=0.0003, betas=(0.5, 0.999)
),
}
loaders = {
"train": DataLoader(
MNIST(
os.getcwd(), train=True, download=True, transform=ToTensor(),
),
batch_size=32,
),
}
runner = CustomRunner()
runner.train(
model=model,
optimizer=optimizer,
loaders=loaders,
callbacks=[
dl.OptimizerCallback(
optimizer_key="generator", metric_key="loss_generator"
),
dl.OptimizerCallback(
optimizer_key="discriminator", metric_key="loss_discriminator"
),
],
main_metric="loss_generator",
num_epochs=20,
verbose=True,
logdir="./logs_gan",
check=True,
)
def train_experiment(device):
with TemporaryDirectory() as logdir:
latent_dim = 128
generator = nn.Sequential(
# We want to generate 128 coefficients to reshape into a 7x7x128 map
nn.Linear(128, 128 * 7 * 7),
nn.LeakyReLU(0.2, inplace=True),
Lambda(lambda x: x.view(x.size(0), 128, 7, 7)),
nn.ConvTranspose2d(128, 128, (4, 4), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.ConvTranspose2d(128, 128, (4, 4), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(128, 1, (7, 7), padding=3),
nn.Sigmoid(),
)
discriminator = nn.Sequential(
nn.Conv2d(1, 64, (3, 3), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(64, 128, (3, 3), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
GlobalMaxPool2d(),
Flatten(),
nn.Linear(128, 1),
)
model = {"generator": generator, "discriminator": discriminator}
criterion = {
"generator": nn.BCEWithLogitsLoss(),
"discriminator": nn.BCEWithLogitsLoss()
}
optimizer = {
"generator":
torch.optim.Adam(generator.parameters(),
lr=0.0003,
betas=(0.5, 0.999)),
"discriminator":
torch.optim.Adam(discriminator.parameters(),
lr=0.0003,
betas=(0.5, 0.999)),
}
loaders = {
"train":
DataLoader(MNIST(os.getcwd(),
train=False,
download=True,
transform=ToTensor()),
batch_size=32),
}
class CustomRunner(dl.Runner):
def predict_batch(self, batch):
batch_size = 1
# Sample random points in the latent space
random_latent_vectors = torch.randn(batch_size,
latent_dim).to(self.device)
# Decode them to fake images
generated_images = self.model["generator"](
random_latent_vectors).detach()
return generated_images
def handle_batch(self, batch):
real_images, _ = batch
batch_size = real_images.shape[0]
# Sample random points in the latent space
random_latent_vectors = torch.randn(batch_size,
latent_dim).to(self.device)
# Decode them to fake images
generated_images = self.model["generator"](
random_latent_vectors).detach()
# Combine them with real images
combined_images = torch.cat([generated_images, real_images])
# Assemble labels discriminating real from fake images
labels = torch.cat([
torch.ones((batch_size, 1)),
torch.zeros((batch_size, 1))
]).to(self.device)
# Add random noise to the labels - important trick!
labels += 0.05 * torch.rand(labels.shape).to(self.device)
# Discriminator forward
combined_predictions = self.model["discriminator"](
combined_images)
# Sample random points in the latent space
random_latent_vectors = torch.randn(batch_size,
latent_dim).to(self.device)
# Assemble labels that say "all real images"
misleading_labels = torch.zeros(
(batch_size, 1)).to(self.device)
# Generator forward
generated_images = self.model["generator"](
random_latent_vectors)
generated_predictions = self.model["discriminator"](
generated_images)
self.batch = {
"combined_predictions": combined_predictions,
"labels": labels,
"generated_predictions": generated_predictions,
"misleading_labels": misleading_labels,
}
runner = CustomRunner()
runner.train(
engine=dl.DeviceEngine(device),
model=model,
criterion=criterion,
optimizer=optimizer,
loaders=loaders,
callbacks=[
dl.CriterionCallback(
input_key="combined_predictions",
target_key="labels",
metric_key="loss_discriminator",
criterion_key="discriminator",
),
dl.CriterionCallback(
input_key="generated_predictions",
target_key="misleading_labels",
metric_key="loss_generator",
criterion_key="generator",
),
dl.OptimizerCallback(
model_key="generator",
optimizer_key="generator",
metric_key="loss_generator",
),
dl.OptimizerCallback(
model_key="discriminator",
optimizer_key="discriminator",
metric_key="loss_discriminator",
),
],
valid_loader="train",
valid_metric="loss_generator",
minimize_valid_metric=True,
num_epochs=1,
verbose=False,
logdir=logdir,
)
runner.predict_batch(None)[0, 0].cpu().numpy()
nn.Linear(128, 128 * 7 * 7),
nn.LeakyReLU(0.2, inplace=True),
Lambda(lambda x: x.view(x.size(0), 128, 7, 7)),
nn.ConvTranspose2d(128, 128, (4, 4), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.ConvTranspose2d(128, 128, (4, 4), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(128, 1, (7, 7), padding=3),
nn.Sigmoid(),
)
discriminator = nn.Sequential(
nn.Conv2d(1, 64, (3, 3), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(64, 128, (3, 3), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
GlobalMaxPool2d(),
Flatten(),
nn.Linear(128, 1),
)
model = {"generator": generator, "discriminator": discriminator}
optimizer = {
"generator":
torch.optim.Adam(generator.parameters(), lr=0.0003, betas=(0.5, 0.999)),
"discriminator":
torch.optim.Adam(discriminator.parameters(), lr=0.0003,
betas=(0.5, 0.999)),
}
loaders = {
"train":
DataLoader(
# We want to generate 128 coefficients to reshape into a 7x7x128 map
nn.Linear(128, 128 * 7 * 7),
nn.LeakyReLU(0.2, inplace=True),
Lambda(lambda x: x.view(x.size(0), 128, 7, 7)),
nn.ConvTranspose2d(128, 128, (4, 4), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.ConvTranspose2d(128, 128, (4, 4), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(128, 1, (7, 7), padding=3),
nn.Sigmoid(),
)
discriminator = nn.Sequential(
nn.Conv2d(1, 64, (3, 3), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True),
nn.Conv2d(64, 128, (3, 3), stride=(2, 2), padding=1),
nn.LeakyReLU(0.2, inplace=True), GlobalMaxPool2d(), Flatten(),
nn.Linear(128, 1))
model = {"generator": generator, "discriminator": discriminator}
optimizer = {
"generator":
torch.optim.Adam(generator.parameters(), lr=0.0003, betas=(0.5, 0.999)),
"discriminator":
torch.optim.Adam(discriminator.parameters(), lr=0.0003,
betas=(0.5, 0.999)),
}
loaders = {
"train":
DataLoader(MNIST(os.getcwd(),
train=True,
download=True,