File size: 13,760 Bytes
f08eddf |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 |
from dataclasses import dataclass
from typing import Optional, Tuple
import numpy as np
import torch
import torch.nn as nn
from diffusers.utils import BaseOutput, is_torch_version
from diffusers.utils.torch_utils import randn_tensor
from diffusers.models.attention_processor import SpatialNorm
from .unet_causal_3d_blocks import (
CausalConv3d,
UNetMidBlockCausal3D,
get_down_block3d,
get_up_block3d,
)
@dataclass
class DecoderOutput(BaseOutput):
r"""
Output of decoding method.
Args:
sample (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`):
The decoded output sample from the last layer of the model.
"""
sample: torch.FloatTensor
class EncoderCausal3D(nn.Module):
r"""
The `EncoderCausal3D` layer of a variational autoencoder that encodes its input into a latent representation.
"""
def __init__(
self,
in_channels: int = 3,
out_channels: int = 3,
down_block_types: Tuple[str, ...] = ("DownEncoderBlockCausal3D",),
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,
time_compression_ratio: int = 4,
spatial_compression_ratio: int = 8,
):
super().__init__()
self.layers_per_block = layers_per_block
self.conv_in = CausalConv3d(in_channels, block_out_channels[0], kernel_size=3, stride=1)
self.mid_block = None
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
num_spatial_downsample_layers = int(np.log2(spatial_compression_ratio))
num_time_downsample_layers = int(np.log2(time_compression_ratio))
if time_compression_ratio == 4:
add_spatial_downsample = bool(i < num_spatial_downsample_layers)
add_time_downsample = bool(
i >= (len(block_out_channels) - 1 - num_time_downsample_layers)
and not is_final_block
)
else:
raise ValueError(f"Unsupported time_compression_ratio: {time_compression_ratio}.")
downsample_stride_HW = (2, 2) if add_spatial_downsample else (1, 1)
downsample_stride_T = (2,) if add_time_downsample else (1,)
downsample_stride = tuple(downsample_stride_T + downsample_stride_HW)
down_block = get_down_block3d(
down_block_type,
num_layers=self.layers_per_block,
in_channels=input_channel,
out_channels=output_channel,
add_downsample=bool(add_spatial_downsample or add_time_downsample),
downsample_stride=downsample_stride,
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 = UNetMidBlockCausal3D(
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 = CausalConv3d(block_out_channels[-1], conv_out_channels, kernel_size=3)
def forward(self, sample: torch.FloatTensor) -> torch.FloatTensor:
r"""The forward method of the `EncoderCausal3D` class."""
assert len(sample.shape) == 5, "The input tensor should have 5 dimensions"
sample = self.conv_in(sample)
# 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 DecoderCausal3D(nn.Module):
r"""
The `DecoderCausal3D` layer of a variational autoencoder that decodes its latent representation into an output sample.
"""
def __init__(
self,
in_channels: int = 3,
out_channels: int = 3,
up_block_types: Tuple[str, ...] = ("UpDecoderBlockCausal3D",),
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,
time_compression_ratio: int = 4,
spatial_compression_ratio: int = 8,
):
super().__init__()
self.layers_per_block = layers_per_block
self.conv_in = CausalConv3d(in_channels, block_out_channels[-1], kernel_size=3, stride=1)
self.mid_block = None
self.up_blocks = nn.ModuleList([])
temb_channels = in_channels if norm_type == "spatial" else None
# mid
self.mid_block = UNetMidBlockCausal3D(
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
num_spatial_upsample_layers = int(np.log2(spatial_compression_ratio))
num_time_upsample_layers = int(np.log2(time_compression_ratio))
if time_compression_ratio == 4:
add_spatial_upsample = bool(i < num_spatial_upsample_layers)
add_time_upsample = bool(
i >= len(block_out_channels) - 1 - num_time_upsample_layers
and not is_final_block
)
else:
raise ValueError(f"Unsupported time_compression_ratio: {time_compression_ratio}.")
upsample_scale_factor_HW = (2, 2) if add_spatial_upsample else (1, 1)
upsample_scale_factor_T = (2,) if add_time_upsample else (1,)
upsample_scale_factor = tuple(upsample_scale_factor_T + upsample_scale_factor_HW)
up_block = get_up_block3d(
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=bool(add_spatial_upsample or add_time_upsample),
upsample_scale_factor=upsample_scale_factor,
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 = CausalConv3d(block_out_channels[0], out_channels, kernel_size=3)
self.gradient_checkpointing = False
def forward(
self,
sample: torch.FloatTensor,
latent_embeds: Optional[torch.FloatTensor] = None,
) -> torch.FloatTensor:
r"""The forward method of the `DecoderCausal3D` class."""
assert len(sample.shape) == 5, "The input tensor should have 5 dimensions."
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 DiagonalGaussianDistribution(object):
def __init__(self, parameters: torch.Tensor, deterministic: bool = False):
if parameters.ndim == 3:
dim = 2 # (B, L, C)
elif parameters.ndim == 5 or parameters.ndim == 4:
dim = 1 # (B, C, T, H ,W) / (B, C, H, W)
else:
raise NotImplementedError
self.parameters = parameters
self.mean, self.logvar = torch.chunk(parameters, 2, dim=dim)
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.FloatTensor:
# 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:
reduce_dim = list(range(1, self.mean.ndim))
if other is None:
return 0.5 * torch.sum(
torch.pow(self.mean, 2) + self.var - 1.0 - self.logvar,
dim=reduce_dim,
)
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=reduce_dim,
)
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
|