# Copyright 2024 The HuggingFace Team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from dataclasses import dataclass
from typing import Optional, Tuple
import numpy as np
import torch
import torch.nn as nn
from ...utils import BaseOutput, is_torch_version
from ...utils.torch_utils import randn_tensor
from ..activations import get_activation
from ..attention_processor import SpatialNorm
from ..unets.unet_2d_blocks import (
AutoencoderTinyBlock,
UNetMidBlock2D,
get_down_block,
get_up_block,
)
@dataclass
class DecoderOutput(BaseOutput):
r"""
Output of decoding method.
Args:
sample (`torch.Tensor` of shape `(batch_size, num_channels, height, width)`):
The decoded output sample from the last layer of the model.
"""
sample: torch.Tensor
commit_loss: Optional[torch.FloatTensor] = None
class Encoder(nn.Module):
r"""
The `Encoder` layer of a variational autoencoder that encodes its input into a latent representation.
Args:
in_channels (`int`, *optional*, defaults to 3):
The number of input channels.
out_channels (`int`, *optional*, defaults to 3):
The number of output channels.
down_block_types (`Tuple[str, ...]`, *optional*, defaults to `("DownEncoderBlock2D",)`):
The types of down blocks to use. See `~diffusers.models.unet_2d_blocks.get_down_block` for available
options.
block_out_channels (`Tuple[int, ...]`, *optional*, defaults to `(64,)`):
The number of output channels for each block.
layers_per_block (`int`, *optional*, defaults to 2):
The number of layers per block.
norm_num_groups (`int`, *optional*, defaults to 32):
The number of groups for normalization.
act_fn (`str`, *optional*, defaults to `"silu"`):
The activation function to use. See `~diffusers.models.activations.get_activation` for available options.
double_z (`bool`, *optional*, defaults to `True`):
Whether to double the number of output channels for the last block.
"""
def __init__(
self,
in_channels: int = 3,
out_channels: int = 3,
down_block_types: Tuple[str, ...] = ("DownEncoderBlock2D",),
block_out_channels: Tuple[int, ...] = (64,),
layers_per_block: int = 2,
norm_num_groups: int = 32,
act_fn: str = "silu",
double_z: bool = True,
mid_block_add_attention=True,
):
super().__init__()
self.layers_per_block = layers_per_block
self.conv_in = nn.Conv2d(
in_channels,
block_out_channels[0],
kernel_size=3,
stride=1,
padding=1,
)
self.down_blocks = nn.ModuleList([])
# down
output_channel = block_out_channels[0]
for i, down_block_type in enumerate(down_block_types):
input_channel = output_channel
output_channel = block_out_channels[i]
is_final_block = i == len(block_out_channels) - 1
down_block = get_down_block(
down_block_type,
num_layers=self.layers_per_block,
in_channels=input_channel,
out_channels=output_channel,
add_downsample=not is_final_block,
resnet_eps=1e-6,
downsample_padding=0,
resnet_act_fn=act_fn,
resnet_groups=norm_num_groups,
attention_head_dim=output_channel,
temb_channels=None,
)
self.down_blocks.append(down_block)
# mid
self.mid_block = UNetMidBlock2D(
in_channels=block_out_channels[-1],
resnet_eps=1e-6,
resnet_act_fn=act_fn,
output_scale_factor=1,
resnet_time_scale_shift="default",
attention_head_dim=block_out_channels[-1],
resnet_groups=norm_num_groups,
temb_channels=None,
add_attention=mid_block_add_attention,
)
# out
self.conv_norm_out = nn.GroupNorm(num_channels=block_out_channels[-1], num_groups=norm_num_groups, eps=1e-6)
self.conv_act = nn.SiLU()
conv_out_channels = 2 * out_channels if double_z else out_channels
self.conv_out = nn.Conv2d(block_out_channels[-1], conv_out_channels, 3, padding=1)
self.gradient_checkpointing = False
def forward(self, sample: torch.Tensor) -> torch.Tensor:
r"""The forward method of the `Encoder` class."""
sample = self.conv_in(sample)
if self.training and self.gradient_checkpointing:
def create_custom_forward(module):
def custom_forward(*inputs):
return module(*inputs)
return custom_forward
# down
if is_torch_version(">=", "1.11.0"):
for down_block in self.down_blocks:
sample = torch.utils.checkpoint.checkpoint(
create_custom_forward(down_block), sample, use_reentrant=False
)
# middle
sample = torch.utils.checkpoint.checkpoint(
create_custom_forward(self.mid_block), sample, use_reentrant=False
)
else:
for down_block in self.down_blocks:
sample = torch.utils.checkpoint.checkpoint(create_custom_forward(down_block), sample)
# middle
sample = torch.utils.checkpoint.checkpoint(create_custom_forward(self.mid_block), sample)
else:
# down
for down_block in self.down_blocks:
sample = down_block(sample)
# middle
sample = self.mid_block(sample)
# post-process
sample = self.conv_norm_out(sample)
sample = self.conv_act(sample)
sample = self.conv_out(sample)
return sample
class Decoder(nn.Module):
r"""
The `Decoder` layer of a variational autoencoder that decodes its latent representation into an output sample.
Args:
in_channels (`int`, *optional*, defaults to 3):
The number of input channels.
out_channels (`int`, *optional*, defaults to 3):
The number of output channels.
up_block_types (`Tuple[str, ...]`, *optional*, defaults to `("UpDecoderBlock2D",)`):
The types of up blocks to use. See `~diffusers.models.unet_2d_blocks.get_up_block` for available options.
block_out_channels (`Tuple[int, ...]`, *optional*, defaults to `(64,)`):
The number of output channels for each block.
layers_per_block (`int`, *optional*, defaults to 2):
The number of layers per block.
norm_num_groups (`int`, *optional*, defaults to 32):
The number of groups for normalization.
act_fn (`str`, *optional*, defaults to `"silu"`):
The activation function to use. See `~diffusers.models.activations.get_activation` for available options.
norm_type (`str`, *optional*, defaults to `"group"`):
The normalization type to use. Can be either `"group"` or `"spatial"`.
"""
def __init__(
self,
in_channels: int = 3,
out_channels: int = 3,
up_block_types: Tuple[str, ...] = ("UpDecoderBlock2D",),
block_out_channels: Tuple[int, ...] = (64,),
layers_per_block: int = 2,
norm_num_groups: int = 32,
act_fn: str = "silu",
norm_type: str = "group", # group, spatial
mid_block_add_attention=True,
):
super().__init__()
self.layers_per_block = layers_per_block
self.conv_in = nn.Conv2d(
in_channels,
block_out_channels[-1],
kernel_size=3,
stride=1,
padding=1,
)
self.up_blocks = nn.ModuleList([])
temb_channels = in_channels if norm_type == "spatial" else None
# mid
self.mid_block = UNetMidBlock2D(
in_channels=block_out_channels[-1],
resnet_eps=1e-6,
resnet_act_fn=act_fn,
output_scale_factor=1,
resnet_time_scale_shift="default" if norm_type == "group" else norm_type,
attention_head_dim=block_out_channels[-1],
resnet_groups=norm_num_groups,
temb_channels=temb_channels,
add_attention=mid_block_add_attention,
)
# up
reversed_block_out_channels = list(reversed(block_out_channels))
output_channel = reversed_block_out_channels[0]
for i, up_block_type in enumerate(up_block_types):
prev_output_channel = output_channel
output_channel = reversed_block_out_channels[i]
is_final_block = i == len(block_out_channels) - 1
up_block = get_up_block(
up_block_type,
num_layers=self.layers_per_block + 1,
in_channels=prev_output_channel,
out_channels=output_channel,
prev_output_channel=None,
add_upsample=not is_final_block,
resnet_eps=1e-6,
resnet_act_fn=act_fn,
resnet_groups=norm_num_groups,
attention_head_dim=output_channel,
temb_channels=temb_channels,
resnet_time_scale_shift=norm_type,
)
self.up_blocks.append(up_block)
prev_output_channel = output_channel
# out
if norm_type == "spatial":
self.conv_norm_out = SpatialNorm(block_out_channels[0], temb_channels)
else:
self.conv_norm_out = nn.GroupNorm(num_channels=block_out_channels[0], num_groups=norm_num_groups, eps=1e-6)
self.conv_act = nn.SiLU()
self.conv_out = nn.Conv2d(block_out_channels[0], out_channels, 3, padding=1)
self.gradient_checkpointing = False
def forward(
self,
sample: torch.Tensor,
latent_embeds: Optional[torch.Tensor] = None,
) -> torch.Tensor:
r"""The forward method of the `Decoder` class."""
sample = self.conv_in(sample)
upscale_dtype = next(iter(self.up_blocks.parameters())).dtype
if self.training and self.gradient_checkpointing:
def create_custom_forward(module):
def custom_forward(*inputs):
return module(*inputs)
return custom_forward
if is_torch_version(">=", "1.11.0"):
# middle
sample = torch.utils.checkpoint.checkpoint(
create_custom_forward(self.mid_block),
sample,
latent_embeds,
use_reentrant=False,
)
sample = sample.to(upscale_dtype)
# up
for up_block in self.up_blocks:
sample = torch.utils.checkpoint.checkpoint(
create_custom_forward(up_block),
sample,
latent_embeds,
use_reentrant=False,
)
else:
# middle
sample = torch.utils.checkpoint.checkpoint(
create_custom_forward(self.mid_block), sample, latent_embeds
)
sample = sample.to(upscale_dtype)
# up
for up_block in self.up_blocks:
sample = torch.utils.checkpoint.checkpoint(create_custom_forward(up_block), sample, latent_embeds)
else:
# middle
sample = self.mid_block(sample, latent_embeds)
sample = sample.to(upscale_dtype)
# up
for up_block in self.up_blocks:
sample = up_block(sample, latent_embeds)
# post-process
if latent_embeds is None:
sample = self.conv_norm_out(sample)
else:
sample = self.conv_norm_out(sample, latent_embeds)
sample = self.conv_act(sample)
sample = self.conv_out(sample)
return sample
class UpSample(nn.Module):
r"""
The `UpSample` layer of a variational autoencoder that upsamples its input.
Args:
in_channels (`int`, *optional*, defaults to 3):
The number of input channels.
out_channels (`int`, *optional*, defaults to 3):
The number of output channels.
"""
def __init__(
self,
in_channels: int,
out_channels: int,
) -> None:
super().__init__()
self.in_channels = in_channels
self.out_channels = out_channels
self.deconv = nn.ConvTranspose2d(in_channels, out_channels, kernel_size=4, stride=2, padding=1)
def forward(self, x: torch.Tensor) -> torch.Tensor:
r"""The forward method of the `UpSample` class."""
x = torch.relu(x)
x = self.deconv(x)
return x
class MaskConditionEncoder(nn.Module):
"""
used in AsymmetricAutoencoderKL
"""
def __init__(
self,
in_ch: int,
out_ch: int = 192,
res_ch: int = 768,
stride: int = 16,
) -> None:
super().__init__()
channels = []
while stride > 1:
stride = stride // 2
in_ch_ = out_ch * 2
if out_ch > res_ch:
out_ch = res_ch
if stride == 1:
in_ch_ = res_ch
channels.append((in_ch_, out_ch))
out_ch *= 2
out_channels = []
for _in_ch, _out_ch in channels:
out_channels.append(_out_ch)
out_channels.append(channels[-1][0])
layers = []
in_ch_ = in_ch
for l in range(len(out_channels)):
out_ch_ = out_channels[l]
if l == 0 or l == 1:
layers.append(nn.Conv2d(in_ch_, out_ch_, kernel_size=3, stride=1, padding=1))
else:
layers.append(nn.Conv2d(in_ch_, out_ch_, kernel_size=4, stride=2, padding=1))
in_ch_ = out_ch_
self.layers = nn.Sequential(*layers)
def forward(self, x: torch.Tensor, mask=None) -> torch.Tensor:
r"""The forward method of the `MaskConditionEncoder` class."""
out = {}
for l in range(len(self.layers)):
layer = self.layers[l]
x = layer(x)
out[str(tuple(x.shape))] = x
x = torch.relu(x)
return out
class MaskConditionDecoder(nn.Module):
r"""The `MaskConditionDecoder` should be used in combination with [`AsymmetricAutoencoderKL`] to enhance the model's
decoder with a conditioner on the mask and masked image.
Args:
in_channels (`int`, *optional*, defaults to 3):
The number of input channels.
out_channels (`int`, *optional*, defaults to 3):
The number of output channels.
up_block_types (`Tuple[str, ...]`, *optional*, defaults to `("UpDecoderBlock2D",)`):
The types of up blocks to use. See `~diffusers.models.unet_2d_blocks.get_up_block` for available options.
block_out_channels (`Tuple[int, ...]`, *optional*, defaults to `(64,)`):
The number of output channels for each block.
layers_per_block (`int`, *optional*, defaults to 2):
The number of layers per block.
norm_num_groups (`int`, *optional*, defaults to 32):
The number of groups for normalization.
act_fn (`str`, *optional*, defaults to `"silu"`):
The activation function to use. See `~diffusers.models.activations.get_activation` for available options.
norm_type (`str`, *optional*, defaults to `"group"`):
The normalization type to use. Can be either `"group"` or `"spatial"`.
"""
def __init__(
self,
in_channels: int = 3,
out_channels: int = 3,
up_block_types: Tuple[str, ...] = ("UpDecoderBlock2D",),
block_out_channels: Tuple[int, ...] = (64,),
layers_per_block: int = 2,
norm_num_groups: int = 32,
act_fn: str = "silu",
norm_type: str = "group", # group, spatial
):
super().__init__()
self.layers_per_block = layers_per_block
self.conv_in = nn.Conv2d(
in_channels,
block_out_channels[-1],
kernel_size=3,
stride=1,
padding=1,
)
self.up_blocks = nn.ModuleList([])
temb_channels = in_channels if norm_type == "spatial" else None
# mid
self.mid_block = UNetMidBlock2D(
in_channels=block_out_channels[-1],
resnet_eps=1e-6,
resnet_act_fn=act_fn,
output_scale_factor=1,
resnet_time_scale_shift="default" if norm_type == "group" else norm_type,
attention_head_dim=block_out_channels[-1],
resnet_groups=norm_num_groups,
temb_channels=temb_channels,
)
# up
reversed_block_out_channels = list(reversed(block_out_channels))
output_channel = reversed_block_out_channels[0]
for i, up_block_type in enumerate(up_block_types):
prev_output_channel = output_channel
output_channel = reversed_block_out_channels[i]
is_final_block = i == len(block_out_channels) - 1
up_block = get_up_block(
up_block_type,
num_layers=self.layers_per_block + 1,
in_channels=prev_output_channel,
out_channels=output_channel,
prev_output_channel=None,
add_upsample=not is_final_block,
resnet_eps=1e-6,
resnet_act_fn=act_fn,
resnet_groups=norm_num_groups,
attention_head_dim=output_channel,
temb_channels=temb_channels,
resnet_time_scale_shift=norm_type,
)
self.up_blocks.append(up_block)
prev_output_channel = output_channel
# condition encoder
self.condition_encoder = MaskConditionEncoder(
in_ch=out_channels,
out_ch=block_out_channels[0],
res_ch=block_out_channels[-1],
)
# out
if norm_type == "spatial":
self.conv_norm_out = SpatialNorm(block_out_channels[0], temb_channels)
else:
self.conv_norm_out = nn.GroupNorm(num_channels=block_out_channels[0], num_groups=norm_num_groups, eps=1e-6)
self.conv_act = nn.SiLU()
self.conv_out = nn.Conv2d(block_out_channels[0], out_channels, 3, padding=1)
self.gradient_checkpointing = False
def forward(
self,
z: torch.Tensor,
image: Optional[torch.Tensor] = None,
mask: Optional[torch.Tensor] = None,
latent_embeds: Optional[torch.Tensor] = None,
) -> torch.Tensor:
r"""The forward method of the `MaskConditionDecoder` class."""
sample = z
sample = self.conv_in(sample)
upscale_dtype = next(iter(self.up_blocks.parameters())).dtype
if self.training and self.gradient_checkpointing:
def create_custom_forward(module):
def custom_forward(*inputs):
return module(*inputs)
return custom_forward
if is_torch_version(">=", "1.11.0"):
# middle
sample = torch.utils.checkpoint.checkpoint(
create_custom_forward(self.mid_block),
sample,
latent_embeds,
use_reentrant=False,
)
sample = sample.to(upscale_dtype)
# condition encoder
if image is not None and mask is not None:
masked_image = (1 - mask) * image
im_x = torch.utils.checkpoint.checkpoint(
create_custom_forward(self.condition_encoder),
masked_image,
mask,
use_reentrant=False,
)
# up
for up_block in self.up_blocks:
if image is not None and mask is not None:
sample_ = im_x[str(tuple(sample.shape))]
mask_ = nn.functional.interpolate(mask, size=sample.shape[-2:], mode="nearest")
sample = sample * mask_ + sample_ * (1 - mask_)
sample = torch.utils.checkpoint.checkpoint(
create_custom_forward(up_block),
sample,
latent_embeds,
use_reentrant=False,
)
if image is not None and mask is not None:
sample = sample * mask + im_x[str(tuple(sample.shape))] * (1 - mask)
else:
# middle
sample = torch.utils.checkpoint.checkpoint(
create_custom_forward(self.mid_block), sample, latent_embeds
)
sample = sample.to(upscale_dtype)
# condition encoder
if image is not None and mask is not None:
masked_image = (1 - mask) * image
im_x = torch.utils.checkpoint.checkpoint(
create_custom_forward(self.condition_encoder),
masked_image,
mask,
)
# up
for up_block in self.up_blocks:
if image is not None and mask is not None:
sample_ = im_x[str(tuple(sample.shape))]
mask_ = nn.functional.interpolate(mask, size=sample.shape[-2:], mode="nearest")
sample = sample * mask_ + sample_ * (1 - mask_)
sample = torch.utils.checkpoint.checkpoint(create_custom_forward(up_block), sample, latent_embeds)
if image is not None and mask is not None:
sample = sample * mask + im_x[str(tuple(sample.shape))] * (1 - mask)
else:
# middle
sample = self.mid_block(sample, latent_embeds)
sample = sample.to(upscale_dtype)
# condition encoder
if image is not None and mask is not None:
masked_image = (1 - mask) * image
im_x = self.condition_encoder(masked_image, mask)
# up
for up_block in self.up_blocks:
if image is not None and mask is not None:
sample_ = im_x[str(tuple(sample.shape))]
mask_ = nn.functional.interpolate(mask, size=sample.shape[-2:], mode="nearest")
sample = sample * mask_ + sample_ * (1 - mask_)
sample = up_block(sample, latent_embeds)
if image is not None and mask is not None:
sample = sample * mask + im_x[str(tuple(sample.shape))] * (1 - mask)
# post-process
if latent_embeds is None:
sample = self.conv_norm_out(sample)
else:
sample = self.conv_norm_out(sample, latent_embeds)
sample = self.conv_act(sample)
sample = self.conv_out(sample)
return sample
class VectorQuantizer(nn.Module):
"""
Improved version over VectorQuantizer, can be used as a drop-in replacement. Mostly avoids costly matrix
multiplications and allows for post-hoc remapping of indices.
"""
# NOTE: due to a bug the beta term was applied to the wrong term. for
# backwards compatibility we use the buggy version by default, but you can
# specify legacy=False to fix it.
def __init__(
self,
n_e: int,
vq_embed_dim: int,
beta: float,
remap=None,
unknown_index: str = "random",
sane_index_shape: bool = False,
legacy: bool = True,
):
super().__init__()
self.n_e = n_e
self.vq_embed_dim = vq_embed_dim
self.beta = beta
self.legacy = legacy
self.embedding = nn.Embedding(self.n_e, self.vq_embed_dim)
self.embedding.weight.data.uniform_(-1.0 / self.n_e, 1.0 / self.n_e)
self.remap = remap
if self.remap is not None:
self.register_buffer("used", torch.tensor(np.load(self.remap)))
self.used: torch.Tensor
self.re_embed = self.used.shape[0]
self.unknown_index = unknown_index # "random" or "extra" or integer
if self.unknown_index == "extra":
self.unknown_index = self.re_embed
self.re_embed = self.re_embed + 1
print(
f"Remapping {self.n_e} indices to {self.re_embed} indices. "
f"Using {self.unknown_index} for unknown indices."
)
else:
self.re_embed = n_e
self.sane_index_shape = sane_index_shape
def remap_to_used(self, inds: torch.LongTensor) -> torch.LongTensor:
ishape = inds.shape
assert len(ishape) > 1
inds = inds.reshape(ishape[0], -1)
used = self.used.to(inds)
match = (inds[:, :, None] == used[None, None, ...]).long()
new = match.argmax(-1)
unknown = match.sum(2) < 1
if self.unknown_index == "random":
new[unknown] = torch.randint(0, self.re_embed, size=new[unknown].shape).to(device=new.device)
else:
new[unknown] = self.unknown_index
return new.reshape(ishape)
def unmap_to_all(self, inds: torch.LongTensor) -> torch.LongTensor:
ishape = inds.shape
assert len(ishape) > 1
inds = inds.reshape(ishape[0], -1)
used = self.used.to(inds)
if self.re_embed > self.used.shape[0]: # extra token
inds[inds >= self.used.shape[0]] = 0 # simply set to zero
back = torch.gather(used[None, :][inds.shape[0] * [0], :], 1, inds)
return back.reshape(ishape)
def forward(self, z: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor, Tuple]:
# reshape z -> (batch, height, width, channel) and flatten
z = z.permute(0, 2, 3, 1).contiguous()
z_flattened = z.view(-1, self.vq_embed_dim)
# distances from z to embeddings e_j (z - e)^2 = z^2 + e^2 - 2 e * z
min_encoding_indices = torch.argmin(torch.cdist(z_flattened, self.embedding.weight), dim=1)
z_q = self.embedding(min_encoding_indices).view(z.shape)
perplexity = None
min_encodings = None
# compute loss for embedding
if not self.legacy:
loss = self.beta * torch.mean((z_q.detach() - z) ** 2) + torch.mean((z_q - z.detach()) ** 2)
else:
loss = torch.mean((z_q.detach() - z) ** 2) + self.beta * torch.mean((z_q - z.detach()) ** 2)
# preserve gradients
z_q: torch.Tensor = z + (z_q - z).detach()
# reshape back to match original input shape
z_q = z_q.permute(0, 3, 1, 2).contiguous()
if self.remap is not None:
min_encoding_indices = min_encoding_indices.reshape(z.shape[0], -1) # add batch axis
min_encoding_indices = self.remap_to_used(min_encoding_indices)
min_encoding_indices = min_encoding_indices.reshape(-1, 1) # flatten
if self.sane_index_shape:
min_encoding_indices = min_encoding_indices.reshape(z_q.shape[0], z_q.shape[2], z_q.shape[3])
return z_q, loss, (perplexity, min_encodings, min_encoding_indices)
def get_codebook_entry(self, indices: torch.LongTensor, shape: Tuple[int, ...]) -> torch.Tensor:
# shape specifying (batch, height, width, channel)
if self.remap is not None:
indices = indices.reshape(shape[0], -1) # add batch axis
indices = self.unmap_to_all(indices)
indices = indices.reshape(-1) # flatten again
# get quantized latent vectors
z_q: torch.Tensor = self.embedding(indices)
if shape is not None:
z_q = z_q.view(shape)
# reshape back to match original input shape
z_q = z_q.permute(0, 3, 1, 2).contiguous()
return z_q
class DiagonalGaussianDistribution(object):
def __init__(self, parameters: torch.Tensor, deterministic: bool = False):
self.parameters = parameters
self.mean, self.logvar = torch.chunk(parameters, 2, dim=1)
self.logvar = torch.clamp(self.logvar, -30.0, 20.0)
self.deterministic = deterministic
self.std = torch.exp(0.5 * self.logvar)
self.var = torch.exp(self.logvar)
if self.deterministic:
self.var = self.std = torch.zeros_like(
self.mean, device=self.parameters.device, dtype=self.parameters.dtype
)
def sample(self, generator: Optional[torch.Generator] = None) -> torch.Tensor:
# make sure sample is on the same device as the parameters and has same dtype
sample = randn_tensor(
self.mean.shape,
generator=generator,
device=self.parameters.device,
dtype=self.parameters.dtype,
)
x = self.mean + self.std * sample
return x
def kl(self, other: "DiagonalGaussianDistribution" = None) -> torch.Tensor:
if self.deterministic:
return torch.Tensor([0.0])
else:
if other is None:
return 0.5 * torch.sum(
torch.pow(self.mean, 2) + self.var - 1.0 - self.logvar,
dim=[1, 2, 3],
)
else:
return 0.5 * torch.sum(
torch.pow(self.mean - other.mean, 2) / other.var
+ self.var / other.var
- 1.0
- self.logvar
+ other.logvar,
dim=[1, 2, 3],
)
def nll(self, sample: torch.Tensor, dims: Tuple[int, ...] = [1, 2, 3]) -> torch.Tensor:
if self.deterministic:
return torch.Tensor([0.0])
logtwopi = np.log(2.0 * np.pi)
return 0.5 * torch.sum(
logtwopi + self.logvar + torch.pow(sample - self.mean, 2) / self.var,
dim=dims,
)
def mode(self) -> torch.Tensor:
return self.mean
class EncoderTiny(nn.Module):
r"""
The `EncoderTiny` layer is a simpler version of the `Encoder` layer.
Args:
in_channels (`int`):
The number of input channels.
out_channels (`int`):
The number of output channels.
num_blocks (`Tuple[int, ...]`):
Each value of the tuple represents a Conv2d layer followed by `value` number of `AutoencoderTinyBlock`'s to
use.
block_out_channels (`Tuple[int, ...]`):
The number of output channels for each block.
act_fn (`str`):
The activation function to use. See `~diffusers.models.activations.get_activation` for available options.
"""
def __init__(
self,
in_channels: int,
out_channels: int,
num_blocks: Tuple[int, ...],
block_out_channels: Tuple[int, ...],
act_fn: str,
):
super().__init__()
layers = []
for i, num_block in enumerate(num_blocks):
num_channels = block_out_channels[i]
if i == 0:
layers.append(nn.Conv2d(in_channels, num_channels, kernel_size=3, padding=1))
else:
layers.append(
nn.Conv2d(
num_channels,
num_channels,
kernel_size=3,
padding=1,
stride=2,
bias=False,
)
)
for _ in range(num_block):
layers.append(AutoencoderTinyBlock(num_channels, num_channels, act_fn))
layers.append(nn.Conv2d(block_out_channels[-1], out_channels, kernel_size=3, padding=1))
self.layers = nn.Sequential(*layers)
self.gradient_checkpointing = False
def forward(self, x: torch.Tensor) -> torch.Tensor:
r"""The forward method of the `EncoderTiny` class."""
if self.training and self.gradient_checkpointing:
def create_custom_forward(module):
def custom_forward(*inputs):
return module(*inputs)
return custom_forward
if is_torch_version(">=", "1.11.0"):
x = torch.utils.checkpoint.checkpoint(create_custom_forward(self.layers), x, use_reentrant=False)
else:
x = torch.utils.checkpoint.checkpoint(create_custom_forward(self.layers), x)
else:
# scale image from [-1, 1] to [0, 1] to match TAESD convention
x = self.layers(x.add(1).div(2))
return x
class DecoderTiny(nn.Module):
r"""
The `DecoderTiny` layer is a simpler version of the `Decoder` layer.
Args:
in_channels (`int`):
The number of input channels.
out_channels (`int`):
The number of output channels.
num_blocks (`Tuple[int, ...]`):
Each value of the tuple represents a Conv2d layer followed by `value` number of `AutoencoderTinyBlock`'s to
use.
block_out_channels (`Tuple[int, ...]`):
The number of output channels for each block.
upsampling_scaling_factor (`int`):
The scaling factor to use for upsampling.
act_fn (`str`):
The activation function to use. See `~diffusers.models.activations.get_activation` for available options.
"""
def __init__(
self,
in_channels: int,
out_channels: int,
num_blocks: Tuple[int, ...],
block_out_channels: Tuple[int, ...],
upsampling_scaling_factor: int,
act_fn: str,
upsample_fn: str,
):
super().__init__()
layers = [
nn.Conv2d(in_channels, block_out_channels[0], kernel_size=3, padding=1),
get_activation(act_fn),
]
for i, num_block in enumerate(num_blocks):
is_final_block = i == (len(num_blocks) - 1)
num_channels = block_out_channels[i]
for _ in range(num_block):
layers.append(AutoencoderTinyBlock(num_channels, num_channels, act_fn))
if not is_final_block:
layers.append(nn.Upsample(scale_factor=upsampling_scaling_factor, mode=upsample_fn))
conv_out_channel = num_channels if not is_final_block else out_channels
layers.append(
nn.Conv2d(
num_channels,
conv_out_channel,
kernel_size=3,
padding=1,
bias=is_final_block,
)
)
self.layers = nn.Sequential(*layers)
self.gradient_checkpointing = False
def forward(self, x: torch.Tensor) -> torch.Tensor:
r"""The forward method of the `DecoderTiny` class."""
# Clamp.
x = torch.tanh(x / 3) * 3
if self.training and self.gradient_checkpointing:
def create_custom_forward(module):
def custom_forward(*inputs):
return module(*inputs)
return custom_forward
if is_torch_version(">=", "1.11.0"):
x = torch.utils.checkpoint.checkpoint(create_custom_forward(self.layers), x, use_reentrant=False)
else:
x = torch.utils.checkpoint.checkpoint(create_custom_forward(self.layers), x)
else:
x = self.layers(x)
# scale image from [0, 1] to [-1, 1] to match diffusers convention
return x.mul(2).sub(1)