def encode_scene(images, viewpoints):
# (batch, views, height, width, channels) -> (batch, views, channels, height, width)
images = images.transpose((0, 1, 4, 2, 3)).astype(np.float32)
# Sample number of views
total_views = images.shape[1]
num_views = random.choice(range(1, total_views + 1))
# Sample views
observation_view_indices = list(range(total_views))
random.shuffle(observation_view_indices)
observation_view_indices = observation_view_indices[:num_views]
observation_images = preprocess_images(
images[:, observation_view_indices])
observation_query = viewpoints[:, observation_view_indices]
representation = model.compute_observation_representation(
observation_images, observation_query)
# Sample query view
query_index = random.choice(range(total_views))
query_images = preprocess_images(images[:, query_index])
query_viewpoints = viewpoints[:, query_index]
# Transfer to gpu if necessary
query_images = to_device(query_images, gpu_device)
query_viewpoints = to_device(query_viewpoints, gpu_device)
return representation, query_images, query_viewpoints
def main():
try:
os.mkdir(args.snapshot_directory)
except:
pass
np.random.seed(0)
xp = np
device_gpu = args.gpu_device
device_cpu = -1
using_gpu = device_gpu >= 0
if using_gpu:
cuda.get_device(args.gpu_device).use()
xp = cupy
dataset = gqn.data.Dataset(args.dataset_directory)
hyperparams = HyperParameters()
hyperparams.generator_share_core = args.generator_share_core
hyperparams.generator_share_prior = args.generator_share_prior
hyperparams.generator_generation_steps = args.generation_steps
hyperparams.generator_share_upsampler = args.generator_share_upsampler
hyperparams.inference_share_core = args.inference_share_core
hyperparams.inference_share_posterior = args.inference_share_posterior
hyperparams.h_channels = args.h_channels
hyperparams.z_channels = args.z_channels
hyperparams.u_channels = args.u_channels
hyperparams.image_size = (args.image_size, args.image_size)
hyperparams.representation_channels = args.representation_channels
hyperparams.representation_architecture = args.representation_architecture
hyperparams.pixel_n = args.pixel_n
hyperparams.pixel_sigma_i = args.initial_pixel_variance
hyperparams.pixel_sigma_f = args.final_pixel_variance
hyperparams.save(args.snapshot_directory)
print(hyperparams)
model = Model(hyperparams,
snapshot_directory=args.snapshot_directory,
optimized=args.optimized)
if using_gpu:
model.to_gpu()
scheduler = Scheduler(sigma_start=args.initial_pixel_variance,
sigma_end=args.final_pixel_variance,
final_num_updates=args.pixel_n,
snapshot_directory=args.snapshot_directory)
print(scheduler)
optimizer = AdamOptimizer(model.parameters,
mu_i=args.initial_lr,
mu_f=args.final_lr,
initial_training_step=scheduler.num_updates)
print(optimizer)
pixel_var = xp.full((args.batch_size, 3) + hyperparams.image_size,
scheduler.pixel_variance**2,
dtype="float32")
pixel_ln_var = xp.full((args.batch_size, 3) + hyperparams.image_size,
math.log(scheduler.pixel_variance**2),
dtype="float32")
representation_shape = (args.batch_size,
hyperparams.representation_channels,
args.image_size // 4, args.image_size // 4)
fig = plt.figure(figsize=(9, 3))
axis_data = fig.add_subplot(1, 3, 1)
axis_data.set_title("Data")
axis_data.axis("off")
axis_reconstruction = fig.add_subplot(1, 3, 2)
axis_reconstruction.set_title("Reconstruction")
axis_reconstruction.axis("off")
axis_generation = fig.add_subplot(1, 3, 3)
axis_generation.set_title("Generation")
axis_generation.axis("off")
current_training_step = 0
for iteration in range(args.training_iterations):
mean_kld = 0
mean_nll = 0
mean_mse = 0
mean_elbo = 0
total_num_batch = 0
start_time = time.time()
for subset_index, subset in enumerate(dataset):
iterator = gqn.data.Iterator(subset, batch_size=args.batch_size)
for batch_index, data_indices in enumerate(iterator):
# shape: (batch, views, height, width, channels)
# range: [-1, 1]
images, viewpoints = subset[data_indices]
# (batch, views, height, width, channels) -> (batch, views, channels, height, width)
images = images.transpose((0, 1, 4, 2, 3)).astype(np.float32)
total_views = images.shape[1]
# Sample number of views
num_views = random.choice(range(1, total_views + 1))
observation_view_indices = list(range(total_views))
random.shuffle(observation_view_indices)
observation_view_indices = observation_view_indices[:num_views]
query_index = random.choice(range(total_views))
if num_views > 0:
observation_images = preprocess_images(
images[:, observation_view_indices])
observation_query = viewpoints[:, observation_view_indices]
representation = model.compute_observation_representation(
observation_images, observation_query)
else:
representation = xp.zeros(representation_shape,
dtype="float32")
representation = chainer.Variable(representation)
# Sample query
query_index = random.choice(range(total_views))
query_images = preprocess_images(images[:, query_index])
query_viewpoints = viewpoints[:, query_index]
# Transfer to gpu if necessary
query_images = to_device(query_images, device_gpu)
query_viewpoints = to_device(query_viewpoints, device_gpu)
z_t_param_array, mean_x = model.sample_z_and_x_params_from_posterior(
query_images, query_viewpoints, representation)
# Compute loss
## KL Divergence
loss_kld = 0
for params in z_t_param_array:
mean_z_q, ln_var_z_q, mean_z_p, ln_var_z_p = params
kld = gqn.functions.gaussian_kl_divergence(
mean_z_q, ln_var_z_q, mean_z_p, ln_var_z_p)
loss_kld += cf.sum(kld)
## Negative log-likelihood of generated image
loss_nll = cf.sum(
gqn.functions.gaussian_negative_log_likelihood(
query_images, mean_x, pixel_var, pixel_ln_var))
# Calculate the average loss value
loss_nll = loss_nll / args.batch_size
loss_kld = loss_kld / args.batch_size
loss = loss_nll / scheduler.pixel_variance + loss_kld
model.cleargrads()
loss.backward()
optimizer.update(current_training_step)
loss_nll = float(loss_nll.data) + math.log(256.0)
loss_kld = float(loss_kld.data)
elbo = -(loss_nll + loss_kld)
loss_mse = float(
cf.mean_squared_error(query_images, mean_x).data)
printr(
"Iteration {}: Subset {} / {}: Batch {} / {} - elbo: {:.2f} - loss: nll: {:.2f} mse: {:.6e} kld: {:.5f} - lr: {:.4e} - pixel_variance: {:.5f} - step: {} "
.format(iteration + 1,
subset_index + 1, len(dataset), batch_index + 1,
len(iterator), elbo, loss_nll, loss_mse, loss_kld,
optimizer.learning_rate, scheduler.pixel_variance,
current_training_step))
scheduler.step(iteration, current_training_step)
pixel_var[...] = scheduler.pixel_variance**2
pixel_ln_var[...] = math.log(scheduler.pixel_variance**2)
total_num_batch += 1
current_training_step += 1
mean_kld += loss_kld
mean_nll += loss_nll
mean_mse += loss_mse
mean_elbo += elbo
model.serialize(args.snapshot_directory)
# Visualize
if args.with_visualization:
axis_data.imshow(make_uint8(query_images[0]),
interpolation="none")
axis_reconstruction.imshow(make_uint8(mean_x.data[0]),
interpolation="none")
with chainer.no_backprop_mode():
generated_x = model.generate_image(
query_viewpoints[None, 0], representation[None, 0])
axis_generation.imshow(make_uint8(generated_x[0]),
interpolation="none")
plt.pause(1e-8)
elapsed_time = time.time() - start_time
print(
"\033[2KIteration {} - elbo: {:.2f} - loss: nll: {:.2f} mse: {:.6e} kld: {:.5f} - lr: {:.4e} - pixel_variance: {:.5f} - step: {} - time: {:.3f} min"
.format(iteration + 1, mean_elbo / total_num_batch,
mean_nll / total_num_batch, mean_mse / total_num_batch,
mean_kld / total_num_batch, optimizer.learning_rate,
scheduler.pixel_variance, current_training_step,
elapsed_time / 60))
model.serialize(args.snapshot_directory)