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# Copyright (c) 2023 Dominic Rampas MIT License
# Copyright 2023 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.
import math
import numpy as np
import torch
import torch.nn as nn
from ...configuration_utils import ConfigMixin, register_to_config
from ...models.modeling_utils import ModelMixin
from .modeling_wuerstchen_common import AttnBlock, GlobalResponseNorm, TimestepBlock, WuerstchenLayerNorm
class WuerstchenDiffNeXt(ModelMixin, ConfigMixin):
@register_to_config
def __init__(
self,
c_in=4,
c_out=4,
c_r=64,
patch_size=2,
c_cond=1024,
c_hidden=[320, 640, 1280, 1280],
nhead=[-1, 10, 20, 20],
blocks=[4, 4, 14, 4],
level_config=["CT", "CTA", "CTA", "CTA"],
inject_effnet=[False, True, True, True],
effnet_embd=16,
clip_embd=1024,
kernel_size=3,
dropout=0.1,
):
super().__init__()
self.c_r = c_r
self.c_cond = c_cond
if not isinstance(dropout, list):
dropout = [dropout] * len(c_hidden)
# CONDITIONING
self.clip_mapper = nn.Linear(clip_embd, c_cond)
self.effnet_mappers = nn.ModuleList(
[
nn.Conv2d(effnet_embd, c_cond, kernel_size=1) if inject else None
for inject in inject_effnet + list(reversed(inject_effnet))
]
)
self.seq_norm = nn.LayerNorm(c_cond, elementwise_affine=False, eps=1e-6)
self.embedding = nn.Sequential(
nn.PixelUnshuffle(patch_size),
nn.Conv2d(c_in * (patch_size**2), c_hidden[0], kernel_size=1),
WuerstchenLayerNorm(c_hidden[0], elementwise_affine=False, eps=1e-6),
)
def get_block(block_type, c_hidden, nhead, c_skip=0, dropout=0):
if block_type == "C":
return ResBlockStageB(c_hidden, c_skip, kernel_size=kernel_size, dropout=dropout)
elif block_type == "A":
return AttnBlock(c_hidden, c_cond, nhead, self_attn=True, dropout=dropout)
elif block_type == "T":
return TimestepBlock(c_hidden, c_r)
else:
raise ValueError(f"Block type {block_type} not supported")
# BLOCKS
# -- down blocks
self.down_blocks = nn.ModuleList()
for i in range(len(c_hidden)):
down_block = nn.ModuleList()
if i > 0:
down_block.append(
nn.Sequential(
WuerstchenLayerNorm(c_hidden[i - 1], elementwise_affine=False, eps=1e-6),
nn.Conv2d(c_hidden[i - 1], c_hidden[i], kernel_size=2, stride=2),
)
)
for _ in range(blocks[i]):
for block_type in level_config[i]:
c_skip = c_cond if inject_effnet[i] else 0
down_block.append(get_block(block_type, c_hidden[i], nhead[i], c_skip=c_skip, dropout=dropout[i]))
self.down_blocks.append(down_block)
# -- up blocks
self.up_blocks = nn.ModuleList()
for i in reversed(range(len(c_hidden))):
up_block = nn.ModuleList()
for j in range(blocks[i]):
for k, block_type in enumerate(level_config[i]):
c_skip = c_hidden[i] if i < len(c_hidden) - 1 and j == k == 0 else 0
c_skip += c_cond if inject_effnet[i] else 0
up_block.append(get_block(block_type, c_hidden[i], nhead[i], c_skip=c_skip, dropout=dropout[i]))
if i > 0:
up_block.append(
nn.Sequential(
WuerstchenLayerNorm(c_hidden[i], elementwise_affine=False, eps=1e-6),
nn.ConvTranspose2d(c_hidden[i], c_hidden[i - 1], kernel_size=2, stride=2),
)
)
self.up_blocks.append(up_block)
# OUTPUT
self.clf = nn.Sequential(
WuerstchenLayerNorm(c_hidden[0], elementwise_affine=False, eps=1e-6),
nn.Conv2d(c_hidden[0], 2 * c_out * (patch_size**2), kernel_size=1),
nn.PixelShuffle(patch_size),
)
# --- WEIGHT INIT ---
self.apply(self._init_weights)
def _init_weights(self, m):
# General init
if isinstance(m, (nn.Conv2d, nn.Linear)):
nn.init.xavier_uniform_(m.weight)
if m.bias is not None:
nn.init.constant_(m.bias, 0)
for mapper in self.effnet_mappers:
if mapper is not None:
nn.init.normal_(mapper.weight, std=0.02) # conditionings
nn.init.normal_(self.clip_mapper.weight, std=0.02) # conditionings
nn.init.xavier_uniform_(self.embedding[1].weight, 0.02) # inputs
nn.init.constant_(self.clf[1].weight, 0) # outputs
# blocks
for level_block in self.down_blocks + self.up_blocks:
for block in level_block:
if isinstance(block, ResBlockStageB):
block.channelwise[-1].weight.data *= np.sqrt(1 / sum(self.config.blocks))
elif isinstance(block, TimestepBlock):
nn.init.constant_(block.mapper.weight, 0)
def gen_r_embedding(self, r, max_positions=10000):
r = r * max_positions
half_dim = self.c_r // 2
emb = math.log(max_positions) / (half_dim - 1)
emb = torch.arange(half_dim, device=r.device).float().mul(-emb).exp()
emb = r[:, None] * emb[None, :]
emb = torch.cat([emb.sin(), emb.cos()], dim=1)
if self.c_r % 2 == 1: # zero pad
emb = nn.functional.pad(emb, (0, 1), mode="constant")
return emb.to(dtype=r.dtype)
def gen_c_embeddings(self, clip):
clip = self.clip_mapper(clip)
clip = self.seq_norm(clip)
return clip
def _down_encode(self, x, r_embed, effnet, clip=None):
level_outputs = []
for i, down_block in enumerate(self.down_blocks):
effnet_c = None
for block in down_block:
if isinstance(block, ResBlockStageB):
if effnet_c is None and self.effnet_mappers[i] is not None:
dtype = effnet.dtype
effnet_c = self.effnet_mappers[i](
nn.functional.interpolate(
effnet.float(), size=x.shape[-2:], mode="bicubic", antialias=True, align_corners=True
).to(dtype)
)
skip = effnet_c if self.effnet_mappers[i] is not None else None
x = block(x, skip)
elif isinstance(block, AttnBlock):
x = block(x, clip)
elif isinstance(block, TimestepBlock):
x = block(x, r_embed)
else:
x = block(x)
level_outputs.insert(0, x)
return level_outputs
def _up_decode(self, level_outputs, r_embed, effnet, clip=None):
x = level_outputs[0]
for i, up_block in enumerate(self.up_blocks):
effnet_c = None
for j, block in enumerate(up_block):
if isinstance(block, ResBlockStageB):
if effnet_c is None and self.effnet_mappers[len(self.down_blocks) + i] is not None:
dtype = effnet.dtype
effnet_c = self.effnet_mappers[len(self.down_blocks) + i](
nn.functional.interpolate(
effnet.float(), size=x.shape[-2:], mode="bicubic", antialias=True, align_corners=True
).to(dtype)
)
skip = level_outputs[i] if j == 0 and i > 0 else None
if effnet_c is not None:
if skip is not None:
skip = torch.cat([skip, effnet_c], dim=1)
else:
skip = effnet_c
x = block(x, skip)
elif isinstance(block, AttnBlock):
x = block(x, clip)
elif isinstance(block, TimestepBlock):
x = block(x, r_embed)
else:
x = block(x)
return x
def forward(self, x, r, effnet, clip=None, x_cat=None, eps=1e-3, return_noise=True):
if x_cat is not None:
x = torch.cat([x, x_cat], dim=1)
# Process the conditioning embeddings
r_embed = self.gen_r_embedding(r)
if clip is not None:
clip = self.gen_c_embeddings(clip)
# Model Blocks
x_in = x
x = self.embedding(x)
level_outputs = self._down_encode(x, r_embed, effnet, clip)
x = self._up_decode(level_outputs, r_embed, effnet, clip)
a, b = self.clf(x).chunk(2, dim=1)
b = b.sigmoid() * (1 - eps * 2) + eps
if return_noise:
return (x_in - a) / b
else:
return a, b
class ResBlockStageB(nn.Module):
def __init__(self, c, c_skip=None, kernel_size=3, dropout=0.0):
super().__init__()
self.depthwise = nn.Conv2d(c, c, kernel_size=kernel_size, padding=kernel_size // 2, groups=c)
self.norm = WuerstchenLayerNorm(c, elementwise_affine=False, eps=1e-6)
self.channelwise = nn.Sequential(
nn.Linear(c + c_skip, c * 4),
nn.GELU(),
GlobalResponseNorm(c * 4),
nn.Dropout(dropout),
nn.Linear(c * 4, c),
)
def forward(self, x, x_skip=None):
x_res = x
x = self.norm(self.depthwise(x))
if x_skip is not None:
x = torch.cat([x, x_skip], dim=1)
x = self.channelwise(x.permute(0, 2, 3, 1)).permute(0, 3, 1, 2)
return x + x_res
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