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import torch
import torch.nn as nn
import torch.nn.functional as F
import torch
import torch.nn as nn
import xformers.ops as xops
from einops import rearrange
from torch.nn import functional as F
import numbers
class RMSNorm(nn.Module):
def __init__(self, dim, eps=1e-6):
super(RMSNorm, self).__init__()
self.eps = eps
self.scale = nn.Parameter(torch.ones(dim))
def forward(self, x):
rms = torch.sqrt(torch.mean(x**2, dim=-1, keepdim=True) + self.eps)
return self.scale * x / rms
class ResidualBlock(nn.Module):
def __init__(self, in_planes, planes, norm_fn='group', stride=1):
super(ResidualBlock, self).__init__()
self.conv1 = nn.Conv2d(in_planes, planes, kernel_size=3, padding=1, stride=stride)
self.conv2 = nn.Conv2d(planes, planes, kernel_size=3, padding=1)
self.relu = nn.ReLU(inplace=True)
num_groups = planes // 8
if norm_fn == 'group':
self.norm1 = nn.GroupNorm(num_groups=num_groups, num_channels=planes)
self.norm2 = nn.GroupNorm(num_groups=num_groups, num_channels=planes)
if not (stride == 1 and in_planes == planes):
self.norm3 = nn.GroupNorm(num_groups=num_groups, num_channels=planes)
elif norm_fn == 'batch':
self.norm1 = nn.BatchNorm2d(planes)
self.norm2 = nn.BatchNorm2d(planes)
if not (stride == 1 and in_planes == planes):
self.norm3 = nn.BatchNorm2d(planes)
elif norm_fn == 'instance':
self.norm1 = nn.InstanceNorm2d(planes)
self.norm2 = nn.InstanceNorm2d(planes)
if not (stride == 1 and in_planes == planes):
self.norm3 = nn.InstanceNorm2d(planes)
elif norm_fn == 'none':
self.norm1 = nn.Sequential()
self.norm2 = nn.Sequential()
if not (stride == 1 and in_planes == planes):
self.norm3 = nn.Sequential()
if stride == 1 and in_planes == planes:
self.downsample = None
else:
self.downsample = nn.Sequential(
nn.Conv2d(in_planes, planes, kernel_size=1, stride=stride), self.norm3)
def forward(self, x):
y = x
y = self.conv1(y)
y = self.norm1(y)
y = self.relu(y)
y = self.conv2(y)
y = self.norm2(y)
y = self.relu(y)
if self.downsample is not None:
x = self.downsample(x)
return self.relu(x + y)
class UnetExtractor(nn.Module):
def __init__(self, in_channel=3, encoder_dim=[256, 256, 256], norm_fn='group'):
super().__init__()
self.in_ds = nn.Sequential(
nn.Conv2d(in_channel, 64, kernel_size=7, stride=2, padding=3),
nn.GroupNorm(num_groups=8, num_channels=64),
nn.ReLU(inplace=True)
)
self.res1 = nn.Sequential(
ResidualBlock(64, encoder_dim[0], stride=2, norm_fn=norm_fn),
ResidualBlock(encoder_dim[0], encoder_dim[0], norm_fn=norm_fn)
)
self.res2 = nn.Sequential(
ResidualBlock(encoder_dim[0], encoder_dim[1], stride=2, norm_fn=norm_fn),
ResidualBlock(encoder_dim[1], encoder_dim[1], norm_fn=norm_fn)
)
self.res3 = nn.Sequential(
ResidualBlock(encoder_dim[1], encoder_dim[2], stride=2, norm_fn=norm_fn),
ResidualBlock(encoder_dim[2], encoder_dim[2], norm_fn=norm_fn),
)
def forward(self, x):
x = self.in_ds(x)
x1 = self.res1(x)
x2 = self.res2(x1)
x3 = self.res3(x2)
return x1, x2, x3
class MultiBasicEncoder(nn.Module):
def __init__(self, output_dim=[128], encoder_dim=[64, 96, 128]):
super(MultiBasicEncoder, self).__init__()
# output convolution for feature
self.conv2 = nn.Sequential(
ResidualBlock(encoder_dim[2], encoder_dim[2], stride=1),
nn.Conv2d(encoder_dim[2], encoder_dim[2] * 2, 3, padding=1))
# output convolution for context
output_list = []
for dim in output_dim:
conv_out = nn.Sequential(
ResidualBlock(encoder_dim[2], encoder_dim[2], stride=1),
nn.Conv2d(encoder_dim[2], dim[2], 3, padding=1))
output_list.append(conv_out)
self.outputs08 = nn.ModuleList(output_list)
def forward(self, x):
feat1, feat2 = self.conv2(x).split(dim=0, split_size=x.shape[0] // 2)
outputs08 = [f(x) for f in self.outputs08]
return outputs08, feat1, feat2
# attention processor for appreaance head
def _init_weights(m):
if isinstance(m, nn.Linear):
nn.init.normal_(m.weight, std=.02)
if m.bias is not None:
nn.init.constant_(m.bias, 0)
class Mlp(nn.Module):
def __init__(self, in_features, mlp_ratio=4., mlp_bias=False, out_features=None, act_layer=nn.GELU, drop=0.):
super().__init__()
out_features = out_features or in_features
hidden_features = int(in_features * mlp_ratio)
self.fc1 = nn.Linear(in_features, hidden_features, bias=mlp_bias)
self.act = act_layer()
self.fc2 = nn.Linear(hidden_features, out_features, bias=mlp_bias)
self.drop = nn.Dropout(drop)
def forward(self, x):
"""
x: (B, L, D)
Returns: same shape as input
"""
x = self.fc1(x)
x = self.act(x)
x = self.drop(x)
x = self.fc2(x)
x = self.drop(x)
return x
class SelfAttention(nn.Module):
def __init__(self, dim, head_dim=64, qkv_bias=False, qk_scale=None, attn_drop=0., proj_drop=0., use_flashatt_v2=True):
super().__init__()
assert dim % head_dim == 0, 'dim must be divisible by head_dim'
self.num_heads = dim // head_dim
self.scale = qk_scale or head_dim ** -0.5
self.qkv = nn.Linear(dim, dim * 3, bias=qkv_bias)
self.attn_drop_p = attn_drop
self.attn_drop = nn.Dropout(attn_drop)
self.proj = nn.Linear(dim, dim, bias=False)
self.proj_drop = nn.Dropout(proj_drop)
self.norm_q = RMSNorm(head_dim, eps=1e-5)
self.norm_k = RMSNorm(head_dim, eps=1e-5)
self.use_flashatt_v2 = use_flashatt_v2
def forward(self, x):
"""
x: (B, L, D)
Returns: same shape as input
"""
B, N, C = x.shape
qkv = self.qkv(x).reshape(B, N, 3, self.num_heads, C // self.num_heads)
if self.use_flashatt_v2:
qkv = qkv.permute(2, 0, 1, 3, 4)
q, k, v = qkv[0], qkv[1], qkv[2] # (B, N, H, C)
q, k = self.norm_q(q).to(v.dtype), self.norm_k(k).to(v.dtype)
x = xops.memory_efficient_attention(q, k, v, op=(xops.fmha.flash.FwOp, xops.fmha.flash.BwOp), p=self.attn_drop_p)
x = rearrange(x, 'b n h d -> b n (h d)')
x = self.proj(x)
x = self.proj_drop(x)
return x
class CrossAttention(nn.Module):
def __init__(self, dim, head_dim=64, qkv_bias=False, qk_scale=None, attn_drop=0., proj_drop=0., use_flashatt_v2=True):
super().__init__()
assert dim % head_dim == 0, 'dim must be divisible by head_dim'
self.num_heads = dim // head_dim
self.scale = qk_scale or head_dim ** -0.5
self.q = nn.Linear(dim, dim, bias=qkv_bias)
self.k = nn.Linear(dim, dim, bias=qkv_bias)
self.v = nn.Linear(dim, dim, bias=qkv_bias)
self.attn_drop_p = attn_drop
self.attn_drop = nn.Dropout(attn_drop)
self.proj = nn.Linear(dim, dim, bias=False)
self.proj_drop = nn.Dropout(proj_drop)
self.norm_q = RMSNorm(head_dim, eps=1e-5)
self.norm_k = RMSNorm(head_dim, eps=1e-5)
self.use_flashatt_v2 = use_flashatt_v2
def forward(self, x_q, x_kv):
"""
x_q: query input (B, L_q, D)
x_kv: key-value input (B, L_kv, D)
Returns: same shape as query input (B, L_q, D)
"""
B, N_q, C = x_q.shape
_, N_kv, _ = x_kv.shape
q = self.q(x_q).reshape(B, N_q, self.num_heads, C // self.num_heads)
k = self.k(x_kv).reshape(B, N_kv, self.num_heads, C // self.num_heads)
v = self.v(x_kv).reshape(B, N_kv, self.num_heads, C // self.num_heads)
if self.use_flashatt_v2:
q, k = self.norm_q(q).to(v.dtype), self.norm_k(k).to(v.dtype)
x = xops.memory_efficient_attention(
q, k, v,
op=(xops.fmha.flash.FwOp, xops.fmha.flash.BwOp),
p=self.attn_drop_p
)
x = rearrange(x, 'b n h d -> b n (h d)')
x = self.proj(x)
x = self.proj_drop(x)
return x
class TransformerBlockSelfAttn(nn.Module):
def __init__(self, dim, head_dim, mlp_ratio=4., mlp_bias=False, qkv_bias=False, qk_scale=None, drop=0., attn_drop=0.,
drop_path=0., act_layer=nn.GELU, norm_layer=nn.LayerNorm, use_flashatt_v2=True):
super().__init__()
self.norm1 = norm_layer(dim, bias=False)
self.attn = SelfAttention(
dim, head_dim=head_dim, qkv_bias=qkv_bias, qk_scale=qk_scale, attn_drop=attn_drop, proj_drop=drop, use_flashatt_v2=use_flashatt_v2)
self.norm2 = norm_layer(dim, bias=False)
self.mlp = Mlp(in_features=dim, mlp_ratio=mlp_ratio, mlp_bias=mlp_bias, act_layer=act_layer, drop=drop)
def forward(self, x):
"""
x: (B, L, D)
Returns: same shape as input
"""
y = self.attn(self.norm1(x))
x = x + y
x = x + self.mlp(self.norm2(x))
return x
class TransformerBlockCrossAttn(nn.Module):
def __init__(self, dim, head_dim, mlp_ratio=4., mlp_bias=False, qkv_bias=False, qk_scale=None, drop=0., attn_drop=0.,
drop_path=0., act_layer=nn.GELU, norm_layer=nn.LayerNorm, use_flashatt_v2=True):
super().__init__()
self.norm1 = norm_layer(dim, bias=False)
self.attn = CrossAttention(
dim, head_dim=head_dim, qkv_bias=qkv_bias, qk_scale=qk_scale, attn_drop=attn_drop, proj_drop=drop, use_flashatt_v2=use_flashatt_v2)
self.norm2 = norm_layer(dim, bias=False)
self.mlp = Mlp(in_features=dim, mlp_ratio=mlp_ratio, mlp_bias=mlp_bias, act_layer=act_layer, drop=drop)
def forward(self, x_list):
"""
x_q: (B, L_q, D)
x_kv: (B, L_kv, D)
Returns: same shape as input
"""
x_q, x_kv = x_list
y = self.attn(self.norm1(x_q), self.norm1(x_kv))
x = x_q + y
x = x + self.mlp(self.norm2(x))
return x
class AppearanceTransformer(nn.Module):
def __init__(self, num_layers, attn_dim, head_dim, ca_incides=[1, 3, 5, 7]):
super().__init__()
self.attn_dim = attn_dim
self.num_layers = num_layers
self.blocks = nn.ModuleList()
self.ca_incides = ca_incides
for attn_index in range(num_layers):
self.blocks.append(TransformerBlockSelfAttn(self.attn_dim, head_dim))
self.blocks[-1].apply(_init_weights)
def forward(self, x, use_checkpoint=True):
"""
input_tokens: (B, L, D)
aggregated_tokens: List of (B, L, D)
Returns: B and D remain the same, L might change if there are merge layers
"""
for block in self.blocks:
if use_checkpoint:
x = torch.utils.checkpoint.checkpoint(block, x, use_reentrant=False)
else:
x = block(x)
return x
if __name__ == '__main__':
data = torch.ones((1, 3, 1024, 1024))
model = UnetExtractor(in_channel=3, encoder_dim=[64, 96, 128])
x1, x2, x3 = model(data)
print(x1.shape, x2.shape, x3.shape)
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