def _create_vector_base_transform(
i,
base_transform_type,
features,
hidden_features,
num_transform_blocks,
dropout_probability,
use_batch_norm,
num_bins,
tail_bound,
apply_unconditional_transform,
context_features,
):
transform_net_create_fn = lambda in_features, out_features: nn_.ResidualNet(
in_features=in_features,
out_features=out_features,
hidden_features=hidden_features,
context_features=context_features,
num_blocks=num_transform_blocks,
activation=F.relu,
dropout_probability=dropout_probability,
use_batch_norm=use_batch_norm,
)
if base_transform_type == "affine-coupling":
return transforms.AffineCouplingTransform(
mask=various.create_alternating_binary_mask(features,
even=(i % 2 == 0)),
transform_net_create_fn=transform_net_create_fn)
elif base_transform_type == "quadratic-coupling":
return transforms.PiecewiseQuadraticCouplingTransform(
mask=various.create_alternating_binary_mask(features,
even=(i % 2 == 0)),
transform_net_create_fn=transform_net_create_fn,
num_bins=num_bins,
tails="linear",
tail_bound=tail_bound,
apply_unconditional_transform=apply_unconditional_transform,
)
elif base_transform_type == "rq-coupling":
return transforms.PiecewiseRationalQuadraticCouplingTransform(
mask=various.create_alternating_binary_mask(features,
even=(i % 2 == 0)),
transform_net_create_fn=transform_net_create_fn,
num_bins=num_bins,
tails="linear",
tail_bound=tail_bound,
apply_unconditional_transform=apply_unconditional_transform,
)
elif base_transform_type == "affine-autoregressive":
return transforms.MaskedAffineAutoregressiveTransform(
features=features,
hidden_features=hidden_features,
context_features=context_features,
num_blocks=num_transform_blocks,
use_residual_blocks=True,
random_mask=False,
activation=F.relu,
dropout_probability=dropout_probability,
use_batch_norm=use_batch_norm,
)
elif base_transform_type == "quadratic-autoregressive":
return transforms.MaskedPiecewiseQuadraticAutoregressiveTransform(
features=features,
hidden_features=hidden_features,
context_features=context_features,
num_bins=num_bins,
tails="linear",
tail_bound=tail_bound,
num_blocks=num_transform_blocks,
use_residual_blocks=True,
random_mask=False,
activation=F.relu,
dropout_probability=dropout_probability,
use_batch_norm=use_batch_norm,
)
elif base_transform_type == "rq-autoregressive":
return transforms.MaskedPiecewiseRationalQuadraticAutoregressiveTransform(
features=features,
hidden_features=hidden_features,
context_features=context_features,
num_bins=num_bins,
tails="linear",
tail_bound=tail_bound,
num_blocks=num_transform_blocks,
use_residual_blocks=True,
random_mask=False,
activation=F.relu,
dropout_probability=dropout_probability,
use_batch_norm=use_batch_norm,
)
else:
raise ValueError
def _create_image_transform_step(
num_channels,
hidden_channels=96,
context_channels=None,
actnorm=True,
coupling_layer_type="rational_quadratic_spline",
num_res_blocks=3,
resnet_batchnorm=True,
dropout_prob=0.0,
num_bins=8,
tail_bound=3.0,
):
def create_convnet(in_channels, out_channels):
net = nn_.ConvResidualNet(
in_channels=in_channels,
out_channels=out_channels,
hidden_channels=hidden_channels,
context_channels=context_channels,
num_blocks=num_res_blocks,
use_batch_norm=resnet_batchnorm,
dropout_probability=dropout_prob,
)
return net
mask = various.create_mid_split_binary_mask(num_channels)
if coupling_layer_type == "cubic_spline":
coupling_layer = transforms.PiecewiseCubicCouplingTransform(
mask=mask,
transform_net_create_fn=create_convnet,
tails="linear",
tail_bound=tail_bound,
num_bins=num_bins,
apply_unconditional_transform=False,
min_bin_width=0.001,
min_bin_height=0.001,
)
elif coupling_layer_type == "quadratic_spline":
coupling_layer = transforms.PiecewiseQuadraticCouplingTransform(
mask=mask,
transform_net_create_fn=create_convnet,
tails="linear",
tail_bound=tail_bound,
num_bins=num_bins,
apply_unconditional_transform=False,
min_bin_width=0.001,
min_bin_height=0.001,
)
elif coupling_layer_type == "rational_quadratic_spline":
coupling_layer = transforms.PiecewiseRationalQuadraticCouplingTransform(
mask=mask,
transform_net_create_fn=create_convnet,
tails="linear",
tail_bound=tail_bound,
num_bins=num_bins,
apply_unconditional_transform=False,
min_bin_width=0.001,
min_bin_height=0.001,
min_derivative=0.001,
)
elif coupling_layer_type == "affine":
coupling_layer = transforms.AffineCouplingTransform(
mask=mask, transform_net_create_fn=create_convnet)
elif coupling_layer_type == "additive":
coupling_layer = transforms.AdditiveCouplingTransform(
mask=mask, transform_net_create_fn=create_convnet)
else:
raise RuntimeError("Unknown coupling_layer_type")
step_transforms = []
if actnorm:
step_transforms.append(transforms.ActNorm(num_channels))
step_transforms.extend(
[transforms.OneByOneConvolution(num_channels), coupling_layer])
logger.debug(" Flow based on %s", coupling_layer_type)
return transforms.CompositeTransform(step_transforms)
def _create_image_transform_step(
num_channels,
hidden_channels=96,
actnorm=True,
coupling_layer_type="rational_quadratic_spline",
spline_params=None,
use_resnet=True,
num_res_blocks=3,
resnet_batchnorm=True,
dropout_prob=0.0,
):
if use_resnet:
def create_convnet(in_channels, out_channels):
net = nn_.ConvResidualNet(
in_channels=in_channels,
out_channels=out_channels,
hidden_channels=hidden_channels,
num_blocks=num_res_blocks,
use_batch_norm=resnet_batchnorm,
dropout_probability=dropout_prob,
)
return net
else:
if dropout_prob != 0.0:
raise ValueError()
def create_convnet(in_channels, out_channels):
return ConvNet(in_channels, hidden_channels, out_channels)
if spline_params is None:
spline_params = {
"apply_unconditional_transform": False,
"min_bin_height": 0.001,
"min_bin_width": 0.001,
"min_derivative": 0.001,
"num_bins": 4,
"tail_bound": 3.0,
}
mask = various.create_mid_split_binary_mask(num_channels)
if coupling_layer_type == "cubic_spline":
coupling_layer = transforms.PiecewiseCubicCouplingTransform(
mask=mask,
transform_net_create_fn=create_convnet,
tails="linear",
tail_bound=spline_params["tail_bound"],
num_bins=spline_params["num_bins"],
apply_unconditional_transform=spline_params[
"apply_unconditional_transform"],
min_bin_width=spline_params["min_bin_width"],
min_bin_height=spline_params["min_bin_height"],
)
elif coupling_layer_type == "quadratic_spline":
coupling_layer = transforms.PiecewiseQuadraticCouplingTransform(
mask=mask,
transform_net_create_fn=create_convnet,
tails="linear",
tail_bound=spline_params["tail_bound"],
num_bins=spline_params["num_bins"],
apply_unconditional_transform=spline_params[
"apply_unconditional_transform"],
min_bin_width=spline_params["min_bin_width"],
min_bin_height=spline_params["min_bin_height"],
)
elif coupling_layer_type == "rational_quadratic_spline":
coupling_layer = transforms.PiecewiseRationalQuadraticCouplingTransform(
mask=mask,
transform_net_create_fn=create_convnet,
tails="linear",
tail_bound=spline_params["tail_bound"],
num_bins=spline_params["num_bins"],
apply_unconditional_transform=spline_params[
"apply_unconditional_transform"],
min_bin_width=spline_params["min_bin_width"],
min_bin_height=spline_params["min_bin_height"],
min_derivative=spline_params["min_derivative"],
)
elif coupling_layer_type == "affine":
coupling_layer = transforms.AffineCouplingTransform(
mask=mask, transform_net_create_fn=create_convnet)
elif coupling_layer_type == "additive":
coupling_layer = transforms.AdditiveCouplingTransform(
mask=mask, transform_net_create_fn=create_convnet)
else:
raise RuntimeError("Unknown coupling_layer_type")
step_transforms = []
if actnorm:
step_transforms.append(transforms.ActNorm(num_channels))
step_transforms.extend(
[transforms.OneByOneConvolution(num_channels), coupling_layer])
logger.debug(" Flow based on %s", coupling_layer_type)
return transforms.CompositeTransform(step_transforms)