cs-mixer / timm /models /tpmlp.py
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import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.utils.checkpoint as checkpoint
from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
from timm.models.helpers import load_pretrained
from timm.models.layers import DropPath, to_2tuple, trunc_normal_
from timm.models.registry import register_model
from einops import rearrange
from einops.layers.torch import Rearrange
from einops._torch_specific import allow_ops_in_compiled_graph # requires einops>=0.6.1
allow_ops_in_compiled_graph()
def _cfg(url='', **kwargs):
return {
'url': url,
'num_classes': 1000, 'input_size': (3, 224, 224), 'pool_size': None,
'crop_pct': .9, 'interpolation': 'bicubic',
'mean': IMAGENET_DEFAULT_MEAN, 'std': IMAGENET_DEFAULT_STD, 'classifier': 'head',
**kwargs
}
class Mlp(nn.Module):
def __init__(self, in_features, hidden_features=None, out_features=None, act_layer=nn.GELU, drop=0.):
super().__init__()
out_features = out_features or in_features
hidden_features = hidden_features or in_features
self.fc1 = nn.Linear(in_features, hidden_features)
self.act = act_layer()
self.fc2 = nn.Linear(hidden_features, out_features)
self.drop = nn.Dropout(drop)
def forward(self, x):
x = self.fc1(x)
x = self.act(x)
x = self.drop(x)
x = self.fc2(x)
x = self.drop(x)
return x
class Attention(nn.Module):
r""" Multi-head self attention module with dynamic position bias.
Args:
dim (int): Number of input channels.
group_size (tuple[int]): The height and width of the group.
num_heads (int): Number of attention heads.
qkv_bias (bool, optional): If True, add a learnable bias to query, key, value. Default: True
qk_scale (float | None, optional): Override default qk scale of head_dim ** -0.5 if set
attn_drop (float, optional): Dropout ratio of attention weight. Default: 0.0
proj_drop (float, optional): Dropout ratio of output. Default: 0.0
"""
def __init__(self, seq_len, dim, group_size, num_heads, qkv_bias=True, qk_scale=None, attn_drop=0., proj_drop=0.,
reduced_dim=2):
super().__init__()
self.dim = dim
self.group_size = group_size # Wh, Ww
self.num_heads = num_heads
self.reduced_dim = reduced_dim
self.to_u = nn.Linear(dim, dim, bias=qkv_bias)
self.to_v = nn.Linear(dim, num_heads * reduced_dim)
self.weight = nn.Parameter(torch.empty(num_heads, seq_len * reduced_dim, seq_len * reduced_dim))
trunc_normal_(self.weight, std=.02)
self.bias = nn.Parameter(torch.zeros(num_heads, seq_len * reduced_dim))
self.v_proj = nn.Linear(num_heads * reduced_dim, dim); self.v_proj.seq_len = seq_len; self.v_proj.stable=True
self.attn_drop = nn.Dropout(attn_drop)
self.proj = nn.Linear(dim, dim)
self.proj_drop = nn.Dropout(proj_drop)
def forward(self, x):
"""
Args:
x: input features with shape of (num_groups*B, N, C)
"""
B_, N, C = x.shape
u, v = self.to_u(x), self.to_v(x)
# x = x.reshape(B, L, self.num_head, C//self.num_head).permute(0, 2, 3, 1)
# x = torch.matmul(x, weights)
# x: b m c//m, L
# weight: (b, m, L, L)
v = torch.matmul(rearrange(v, "b n (m d) -> b m () (n d)", m=self.num_heads, d=self.reduced_dim),
self.weight).squeeze(2) + self.bias
v = rearrange(v, "b m (n d) -> b n (m d)", n=N)
v = self.v_proj(v)
x = u * v
x = self.attn_drop(x)
# x = (attn @ v).transpose(1, 2).reshape(B_, N, C)
x = self.proj(x)
x = self.proj_drop(x)
return x
def extra_repr(self) -> str:
return f'dim={self.dim}, group_size={self.group_size}, num_heads={self.num_heads}'
def flops(self, N):
# calculate flops for 1 group with token length of N
flops = 0
# to_u, to_v
flops += N * self.dim * self.dim
flops += N * self.dim * (self.num_heads * self.reduced_dim)
# weight
flops += self.num_heads * (N * self.reduced_dim) * (N * self.reduced_dim)
# v_proj
flops += N * (self.num_heads * self.reduced_dim) * self.dim
# u * v
flops += N * self.dim
# proj
flops += N * self.dim * self.dim
return flops
class CrossFormerBlock(nn.Module):
r""" CrossFormer Block.
Args:
dim (int): Number of input channels.
input_resolution (tuple[int]): Input resulotion.
num_heads (int): Number of attention heads.
group_size (int): Group size.
lsda_flag (int): use SDA or LDA, 0 for SDA and 1 for LDA.
mlp_ratio (float): Ratio of mlp hidden dim to embedding dim.
qkv_bias (bool, optional): If True, add a learnable bias to query, key, value. Default: True
qk_scale (float | None, optional): Override default qk scale of head_dim ** -0.5 if set.
drop (float, optional): Dropout rate. Default: 0.0
attn_drop (float, optional): Attention dropout rate. Default: 0.0
drop_path (float, optional): Stochastic depth rate. Default: 0.0
act_layer (nn.Module, optional): Activation layer. Default: nn.GELU
norm_layer (nn.Module, optional): Normalization layer. Default: nn.LayerNorm
"""
def __init__(self, dim, input_resolution, num_heads, group_size=7, lsda_flag=0,
mlp_ratio=4., qkv_bias=True, qk_scale=None, drop=0., attn_drop=0., drop_path=0.,
act_layer=nn.GELU, norm_layer=nn.LayerNorm, num_patch_size=1, reduced_dim=2):
super().__init__()
self.dim = dim
self.input_resolution = input_resolution
self.num_heads = num_heads
self.group_size = group_size
self.lsda_flag = lsda_flag
self.mlp_ratio = mlp_ratio
self.num_patch_size = num_patch_size
if min(self.input_resolution) <= self.group_size:
# if group size is larger than input resolution, we don't partition groups
self.lsda_flag = 0
self.group_size = min(self.input_resolution)
self.norm1 = norm_layer(dim)
self.attn = Attention(
seq_len=self.group_size ** 2, dim=dim, group_size=to_2tuple(self.group_size),
num_heads=num_heads, qkv_bias=qkv_bias, qk_scale=qk_scale, attn_drop=attn_drop,
proj_drop=drop, reduced_dim=reduced_dim)
self.drop_path = DropPath(drop_path) if drop_path > 0. else nn.Identity()
self.norm2 = norm_layer(dim)
mlp_hidden_dim = int(dim * mlp_ratio)
self.mlp = Mlp(in_features=dim, hidden_features=mlp_hidden_dim, act_layer=act_layer, drop=drop)
def forward(self, x):
H, W = self.input_resolution
B, L, C = x.shape
assert L == H * W, "input feature has wrong size %d, %d, %d" % (L, H, W)
shortcut = x
x = self.norm1(x)
x = x.view(B, H, W, C)
# group embeddings
G = self.group_size
if self.lsda_flag == 0: # 0 for SDA
x = x.reshape(B, H // G, G, W // G, G, C).permute(0, 1, 3, 2, 4, 5)
else: # 1 for LDA
x = x.reshape(B, G, H // G, G, W // G, C).permute(0, 2, 4, 1, 3, 5)
x = x.reshape(B * H * W // G**2, G**2, C)
# multi-head self-attention
x = self.attn(x) # nW*B, G*G, C
# ungroup embeddings
x = x.reshape(B, H // G, W // G, G, G, C)
if self.lsda_flag == 0:
x = x.permute(0, 1, 3, 2, 4, 5).reshape(B, H, W, C)
else:
x = x.permute(0, 3, 1, 4, 2, 5).reshape(B, H, W, C)
x = x.view(B, H * W, C)
# FFN
x = shortcut + self.drop_path(x)
x = x + self.drop_path(self.mlp(self.norm2(x)))
return x
def extra_repr(self) -> str:
return f"dim={self.dim}, input_resolution={self.input_resolution}, num_heads={self.num_heads}, " \
f"group_size={self.group_size}, lsda_flag={self.lsda_flag}, mlp_ratio={self.mlp_ratio}"
def flops(self):
flops = 0
H, W = self.input_resolution
# norm1
flops += self.dim * H * W
# LSDA
nW = H * W / self.group_size / self.group_size
flops += nW * self.attn.flops(self.group_size * self.group_size)
# mlp
flops += 2 * H * W * self.dim * self.dim * self.mlp_ratio
# norm2
flops += self.dim * H * W
return flops
class PatchMerging(nn.Module):
r""" Patch Merging Layer.
Args:
input_resolution (tuple[int]): Resolution of input feature.
dim (int): Number of input channels.
norm_layer (nn.Module, optional): Normalization layer. Default: nn.LayerNorm
"""
def __init__(self, input_resolution, dim, norm_layer=nn.LayerNorm, patch_size=[2], num_input_patch_size=1):
super().__init__()
self.input_resolution = input_resolution
self.dim = dim
self.reductions = nn.ModuleList()
self.patch_size = patch_size
self.norm = norm_layer(dim)
for i, ps in enumerate(patch_size):
if i == len(patch_size) - 1:
out_dim = 2 * dim // 2 ** i
else:
out_dim = 2 * dim // 2 ** (i + 1)
stride = 2
padding = (ps - stride) // 2
self.reductions.append(nn.Conv2d(dim, out_dim, kernel_size=ps,
stride=stride, padding=padding))
def forward(self, x):
"""
x: B, H*W, C
"""
H, W = self.input_resolution
B, L, C = x.shape
assert L == H * W, "input feature has wrong size"
assert H % 2 == 0 and W % 2 == 0, f"x size ({H}*{W}) are not even."
x = self.norm(x)
x = x.view(B, H, W, C).permute(0, 3, 1, 2)
xs = []
for i in range(len(self.reductions)):
tmp_x = self.reductions[i](x).flatten(2).transpose(1, 2)
xs.append(tmp_x)
x = torch.cat(xs, dim=2)
return x
def extra_repr(self) -> str:
return f"input_resolution={self.input_resolution}, dim={self.dim}"
def flops(self):
H, W = self.input_resolution
flops = H * W * self.dim
for i, ps in enumerate(self.patch_size):
if i == len(self.patch_size) - 1:
out_dim = 2 * self.dim // 2 ** i
else:
out_dim = 2 * self.dim // 2 ** (i + 1)
flops += (H // 2) * (W // 2) * ps * ps * out_dim * self.dim
return flops
class Stage(nn.Module):
""" CrossFormer blocks for one stage.
Args:
dim (int): Number of input channels.
input_resolution (tuple[int]): Input resolution.
depth (int): Number of blocks.
num_heads (int): Number of attention heads.
group_size (int): variable G in the paper, one group has GxG embeddings
mlp_ratio (float): Ratio of mlp hidden dim to embedding dim.
qkv_bias (bool, optional): If True, add a learnable bias to query, key, value. Default: True
qk_scale (float | None, optional): Override default qk scale of head_dim ** -0.5 if set.
drop (float, optional): Dropout rate. Default: 0.0
attn_drop (float, optional): Attention dropout rate. Default: 0.0
drop_path (float | tuple[float], optional): Stochastic depth rate. Default: 0.0
norm_layer (nn.Module, optional): Normalization layer. Default: nn.LayerNorm
downsample (nn.Module | None, optional): Downsample layer at the end of the layer. Default: None
use_checkpoint (bool): Whether to use checkpointing to save memory. Default: False.
"""
def __init__(self, dim, input_resolution, depth, num_heads, group_size,
mlp_ratio=4., qkv_bias=True, qk_scale=None, drop=0., attn_drop=0.,
drop_path=0., norm_layer=nn.LayerNorm, downsample=None, use_checkpoint=False,
patch_size_end=[4], num_patch_size=None, reduced_dim=2):
super().__init__()
self.dim = dim
self.input_resolution = input_resolution
self.depth = depth
self.use_checkpoint = use_checkpoint
# build blocks
self.blocks = nn.ModuleList()
for i in range(depth):
lsda_flag = 0 if (i % 2 == 0) else 1
self.blocks.append(CrossFormerBlock(dim=dim, input_resolution=input_resolution,
num_heads=num_heads, group_size=group_size,
lsda_flag=lsda_flag,
mlp_ratio=mlp_ratio,
qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop, attn_drop=attn_drop,
drop_path=drop_path[i] if isinstance(drop_path, list) else drop_path,
norm_layer=norm_layer,
num_patch_size=num_patch_size,
reduced_dim=reduced_dim))
# patch merging layer
if downsample is not None:
self.downsample = downsample(input_resolution, dim=dim, norm_layer=norm_layer,
patch_size=patch_size_end, num_input_patch_size=num_patch_size)
else:
self.downsample = None
def forward(self, x):
for blk in self.blocks:
if self.use_checkpoint:
x = checkpoint.checkpoint(blk, x)
else:
x = blk(x)
if self.downsample is not None:
x = self.downsample(x)
return x
def extra_repr(self) -> str:
return f"dim={self.dim}, input_resolution={self.input_resolution}, depth={self.depth}"
def flops(self):
flops = 0
for blk in self.blocks:
flops += blk.flops()
if self.downsample is not None:
flops += self.downsample.flops()
return flops
class PatchEmbed(nn.Module):
r""" Image to Patch Embedding
Args:
img_size (int): Image size. Default: 224.
patch_size (int): Patch token size. Default: [4].
in_chans (int): Number of input image channels. Default: 3.
embed_dim (int): Number of linear projection output channels. Default: 96.
norm_layer (nn.Module, optional): Normalization layer. Default: None
"""
def __init__(self, img_size=224, patch_size=[4], in_chans=3, embed_dim=96, norm_layer=None):
super().__init__()
img_size = to_2tuple(img_size)
# patch_size = to_2tuple(patch_size)
patches_resolution = [img_size[0] // patch_size[0], img_size[0] // patch_size[0]]
self.img_size = img_size
self.patch_size = patch_size
self.patches_resolution = patches_resolution
self.num_patches = patches_resolution[0] * patches_resolution[1]
self.in_chans = in_chans
self.embed_dim = embed_dim
self.projs = nn.ModuleList()
for i, ps in enumerate(patch_size):
if i == len(patch_size) - 1:
dim = embed_dim // 2 ** i
else:
dim = embed_dim // 2 ** (i + 1)
stride = patch_size[0]
padding = (ps - patch_size[0]) // 2
self.projs.append(nn.Conv2d(in_chans, dim, kernel_size=ps, stride=stride, padding=padding))
if norm_layer is not None:
self.norm = norm_layer(embed_dim)
else:
self.norm = None
def forward(self, x):
B, C, H, W = x.shape
# FIXME look at relaxing size constraints
assert H == self.img_size[0] and W == self.img_size[1], \
f"Input image size ({H}*{W}) doesn't match model ({self.img_size[0]}*{self.img_size[1]})."
xs = []
for i in range(len(self.projs)):
tx = self.projs[i](x).flatten(2).transpose(1, 2)
xs.append(tx) # B Ph*Pw C
x = torch.cat(xs, dim=2)
if self.norm is not None:
x = self.norm(x)
return x
def flops(self):
Ho, Wo = self.patches_resolution
flops = 0
for i, ps in enumerate(self.patch_size):
if i == len(self.patch_size) - 1:
dim = self.embed_dim // 2 ** i
else:
dim = self.embed_dim // 2 ** (i + 1)
flops += Ho * Wo * dim * self.in_chans * (self.patch_size[i] * self.patch_size[i])
if self.norm is not None:
flops += Ho * Wo * self.embed_dim
return flops
class CrossFormer(nn.Module):
r""" CrossFormer
A PyTorch impl of : `CrossFormer: A Versatile Vision Transformer Based on Cross-scale Attention` -
Args:
img_size (int | tuple(int)): Input image size. Default 224
patch_size (int | tuple(int)): Patch size. Default: 4
in_chans (int): Number of input image channels. Default: 3
num_classes (int): Number of classes for classification head. Default: 1000
embed_dim (int): Patch embedding dimension. Default: 96
depths (tuple(int)): Depth of each stage.
num_heads (tuple(int)): Number of attention heads in different layers.
group_size (int): Group size. Default: 7
mlp_ratio (float): Ratio of mlp hidden dim to embedding dim. Default: 4
qkv_bias (bool): If True, add a learnable bias to query, key, value. Default: True
qk_scale (float): Override default qk scale of head_dim ** -0.5 if set. Default: None
drop_rate (float): Dropout rate. Default: 0
attn_drop_rate (float): Attention dropout rate. Default: 0
drop_path_rate (float): Stochastic depth rate. Default: 0.1
norm_layer (nn.Module): Normalization layer. Default: nn.LayerNorm.
ape (bool): If True, add absolute position embedding to the patch embedding. Default: False
patch_norm (bool): If True, add normalization after patch embedding. Default: True
use_checkpoint (bool): Whether to use checkpointing to save memory. Default: False
"""
def __init__(self, img_size=224, patch_size=[4], in_chans=3, num_classes=1000,
embed_dim=96, depths=[2, 2, 6, 2], num_heads=[3, 6, 12, 24],
group_size=7, mlp_ratio=4., qkv_bias=True, qk_scale=None,
drop_rate=0., attn_drop_rate=0., drop_path_rate=0.1,
norm_layer=nn.LayerNorm, ape=False, patch_norm=True,
use_checkpoint=False, merge_size=[[2], [2], [2]],
reduced_dims=[2, 2, 2, 2], **kwargs):
super().__init__()
self.num_classes = num_classes
self.num_layers = len(depths)
self.embed_dim = embed_dim
self.ape = ape
self.patch_norm = patch_norm
self.num_features = int(embed_dim * 2 ** (self.num_layers - 1))
self.mlp_ratio = mlp_ratio
# split image into non-overlapping patches
self.patch_embed = PatchEmbed(
img_size=img_size, patch_size=patch_size, in_chans=in_chans, embed_dim=embed_dim,
norm_layer=norm_layer if self.patch_norm else None)
num_patches = self.patch_embed.num_patches
patches_resolution = self.patch_embed.patches_resolution
self.patches_resolution = patches_resolution
# absolute position embedding
if self.ape:
self.absolute_pos_embed = nn.Parameter(torch.zeros(1, num_patches, embed_dim))
trunc_normal_(self.absolute_pos_embed, std=.02)
self.pos_drop = nn.Dropout(p=drop_rate)
# stochastic depth
dpr = [x.item() for x in torch.linspace(0, drop_path_rate, sum(depths))] # stochastic depth decay rule
# build layers
self.layers = nn.ModuleList()
num_patch_sizes = [len(patch_size)] + [len(m) for m in merge_size]
for i_layer in range(self.num_layers):
patch_size_end = merge_size[i_layer] if i_layer < self.num_layers - 1 else None
num_patch_size = num_patch_sizes[i_layer]
layer = Stage(dim=int(embed_dim * 2 ** i_layer),
input_resolution=(patches_resolution[0] // (2 ** i_layer),
patches_resolution[1] // (2 ** i_layer)),
depth=depths[i_layer],
num_heads=num_heads[i_layer],
group_size=group_size[i_layer],
mlp_ratio=self.mlp_ratio,
qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop_rate, attn_drop=attn_drop_rate,
drop_path=dpr[sum(depths[:i_layer]):sum(depths[:i_layer + 1])],
norm_layer=norm_layer,
downsample=PatchMerging if (i_layer < self.num_layers - 1) else None,
use_checkpoint=use_checkpoint,
patch_size_end=patch_size_end,
num_patch_size=num_patch_size,
reduced_dim=reduced_dims[i_layer])
self.layers.append(layer)
self.norm = norm_layer(self.num_features)
self.avgpool = nn.AdaptiveAvgPool1d(1)
self.head = nn.Linear(self.num_features, num_classes) if num_classes > 0 else nn.Identity()
self.apply(self._init_weights)
def _init_weights(self, m, init_eps=1e-3):
if isinstance(m, nn.Linear):
if hasattr(m, "stable") and m.stable:
# print("Stable init.")
nn.init.uniform_(m.weight, -init_eps/m.seq_len, init_eps/m.seq_len)
nn.init.constant_(m.bias, 1)
else:
trunc_normal_(m.weight, std=.02)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
@torch.jit.ignore
def no_weight_decay(self):
return {'absolute_pos_embed'}
@torch.jit.ignore
def no_weight_decay_keywords(self):
return {'relative_position_bias_table'}
def forward_features(self, x):
x = self.patch_embed(x)
if self.ape:
x = x + self.absolute_pos_embed
x = self.pos_drop(x)
for layer in self.layers:
x = layer(x)
x = self.norm(x) # B L C
x = self.avgpool(x.transpose(1, 2)) # B C 1
x = torch.flatten(x, 1)
return x
def forward(self, x):
x = self.forward_features(x)
x = self.head(x)
return x
def flops(self):
flops = 0
flops += self.patch_embed.flops()
for i, layer in enumerate(self.layers):
flops += layer.flops()
flops += self.num_features * self.patches_resolution[0] * self.patches_resolution[1] // (2 ** self.num_layers)
flops += self.num_features * self.num_classes
return flops
default_cfgs = {
'TpMLP_S': _cfg(crop_pct=0.9),
'TpMLP_M': _cfg(crop_pct=0.9),
'TpMLP_L': _cfg(crop_pct=0.875),
}
@register_model
def tpmlp_t(pretrained=False, **kwargs):
model = CrossFormer(embed_dim=64, depths=[1, 1, 8, 6], num_heads=[2, 4, 8, 16], group_size=[7, 7, 7, 7],
patch_size=[4, 8, 16, 32], merge_size=[[2, 4], [2, 4], [2, 4]], drop_path_rate=0.1,
reduced_dims=[2, 2, 2, 2], **kwargs)
model.default_cfg = default_cfgs['TpMLP_L']
return model
@register_model
def tpmlp_s(pretrained=False, **kwargs):
model = CrossFormer(embed_dim=96, depths=[2, 2, 6, 2], num_heads=[3, 6, 12, 24], group_size=[7, 7, 7, 7],
patch_size=[4, 8, 16, 32], merge_size=[[2, 4], [2, 4], [2, 4]], drop_path_rate=0.2,
reduced_dims=[4, 4, 4, 4], **kwargs)
model.default_cfg = default_cfgs['TpMLP_L']
return model
@register_model
def tpmlp_b(pretrained=False, **kwargs):
model = CrossFormer(embed_dim=96, depths=[2, 2, 18, 2], num_heads=[3, 6, 12, 24], group_size=[7, 7, 7, 7],
patch_size=[4, 8, 16, 32], merge_size=[[2, 4], [2, 4], [2, 4]], drop_path_rate=0.3,
reduced_dims=[4, 4, 4, 4], **kwargs)
model.default_cfg = default_cfgs['TpMLP_L']
return model
@register_model
def tpmlp_l(pretrained=False, **kwargs):
model = CrossFormer(embed_dim=128, depths=[2, 2, 18, 2], num_heads=[4, 8, 16, 32], group_size=[7, 7, 7, 7],
patch_size=[4, 8, 16, 32], merge_size=[[2, 4], [2, 4], [2, 4]], drop_path_rate=0.5,
reduced_dims=[4, 4, 4, 4], **kwargs)
model.default_cfg = default_cfgs['TpMLP_L']
return model