Create uniformer.py

uniformer.py

@@ -0,0 +1,366 @@
+from collections import OrderedDict
+import torch
+import torch.nn as nn
+from functools import partial
+from timm.models.vision_transformer import _cfg
+from timm.models.registry import register_model
+from timm.models.layers import trunc_normal_, DropPath, to_2tuple
+
+layer_scale = False
+init_value = 1e-6
+
+
+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 CMlp(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.Conv2d(in_features, hidden_features, 1)
+        self.act = act_layer()
+        self.fc2 = nn.Conv2d(hidden_features, out_features, 1)
+        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):
+    def __init__(self, dim, num_heads=8, qkv_bias=False, qk_scale=None, attn_drop=0., proj_drop=0.):
+        super().__init__()
+        self.num_heads = num_heads
+        head_dim = dim // num_heads
+        # NOTE scale factor was wrong in my original version, can set manually to be compat with prev weights
+        self.scale = qk_scale or head_dim ** -0.5
+
+        self.qkv = nn.Linear(dim, dim * 3, bias=qkv_bias)
+        self.attn_drop = nn.Dropout(attn_drop)
+        self.proj = nn.Linear(dim, dim)
+        self.proj_drop = nn.Dropout(proj_drop)
+
+    def forward(self, x):
+        B, N, C = x.shape
+        qkv = self.qkv(x).reshape(B, N, 3, self.num_heads, C // self.num_heads).permute(2, 0, 3, 1, 4)
+        q, k, v = qkv[0], qkv[1], qkv[2]   # make torchscript happy (cannot use tensor as tuple)
+
+        attn = (q @ k.transpose(-2, -1)) * self.scale
+        attn = attn.softmax(dim=-1)
+        attn = self.attn_drop(attn)
+
+        x = (attn @ v).transpose(1, 2).reshape(B, N, C)
+        x = self.proj(x)
+        x = self.proj_drop(x)
+        return x
+
+
+class CBlock(nn.Module):
+    def __init__(self, dim, num_heads, mlp_ratio=4., qkv_bias=False, qk_scale=None, drop=0., attn_drop=0.,
+                 drop_path=0., act_layer=nn.GELU, norm_layer=nn.LayerNorm):
+        super().__init__()
+        self.pos_embed = nn.Conv2d(dim, dim, 3, padding=1, groups=dim)
+        self.norm1 = nn.BatchNorm2d(dim)
+        self.conv1 = nn.Conv2d(dim, dim, 1)
+        self.conv2 = nn.Conv2d(dim, dim, 1)
+        self.attn = nn.Conv2d(dim, dim, 5, padding=2, groups=dim)
+        # NOTE: drop path for stochastic depth, we shall see if this is better than dropout here
+        self.drop_path = DropPath(drop_path) if drop_path > 0. else nn.Identity()
+        self.norm2 = nn.BatchNorm2d(dim)
+        mlp_hidden_dim = int(dim * mlp_ratio)
+        self.mlp = CMlp(in_features=dim, hidden_features=mlp_hidden_dim, act_layer=act_layer, drop=drop)
+
+    def forward(self, x):
+        x = x + self.pos_embed(x)
+        x = x + self.drop_path(self.conv2(self.attn(self.conv1(self.norm1(x)))))
+        x = x + self.drop_path(self.mlp(self.norm2(x)))
+        return x
+
+
+class SABlock(nn.Module):
+    def __init__(self, dim, num_heads, mlp_ratio=4., qkv_bias=False, qk_scale=None, drop=0., attn_drop=0.,
+                 drop_path=0., act_layer=nn.GELU, norm_layer=nn.LayerNorm):
+        super().__init__()
+        self.pos_embed = nn.Conv2d(dim, dim, 3, padding=1, groups=dim)
+        self.norm1 = norm_layer(dim)
+        self.attn = Attention(
+            dim,
+            num_heads=num_heads, qkv_bias=qkv_bias, qk_scale=qk_scale,
+            attn_drop=attn_drop, proj_drop=drop)
+        # NOTE: drop path for stochastic depth, we shall see if this is better than dropout here
+        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)
+        global layer_scale
+        self.ls = layer_scale
+        if self.ls:
+            global init_value
+            print(f"Use layer_scale: {layer_scale}, init_values: {init_value}")
+            self.gamma_1 = nn.Parameter(init_value * torch.ones((dim)),requires_grad=True)
+            self.gamma_2 = nn.Parameter(init_value * torch.ones((dim)),requires_grad=True)
+
+    def forward(self, x):
+        x = x + self.pos_embed(x)
+        B, N, H, W = x.shape
+        x = x.flatten(2).transpose(1, 2)
+        if self.ls:
+            x = x + self.drop_path(self.gamma_1 * self.attn(self.norm1(x)))
+            x = x + self.drop_path(self.gamma_2 * self.mlp(self.norm2(x)))
+        else:
+            x = x + self.drop_path(self.attn(self.norm1(x)))
+            x = x + self.drop_path(self.mlp(self.norm2(x)))
+        x = x.transpose(1, 2).reshape(B, N, H, W)
+        return x        
+   
+
+class head_embedding(nn.Module):
+    def __init__(self, in_channels, out_channels):
+        super(head_embedding, self).__init__()
+
+        self.proj = nn.Sequential(
+            nn.Conv2d(in_channels, out_channels // 2, kernel_size=(3, 3), stride=(2, 2), padding=(1, 1)),
+            nn.BatchNorm2d(out_channels // 2),
+            nn.GELU(),
+            nn.Conv2d(out_channels // 2, out_channels, kernel_size=(3, 3), stride=(2, 2), padding=(1, 1)),
+            nn.BatchNorm2d(out_channels),
+        )
+
+    def forward(self, x):
+        x = self.proj(x)
+        return x
+
+
+class middle_embedding(nn.Module):
+    def __init__(self, in_channels, out_channels):
+        super(middle_embedding, self).__init__()
+
+        self.proj = nn.Sequential(
+            nn.Conv2d(in_channels, out_channels, kernel_size=(3, 3), stride=(2, 2), padding=(1, 1)),
+            nn.BatchNorm2d(out_channels),
+        )
+
+    def forward(self, x):
+        x = self.proj(x)
+        return x
+
+
+class PatchEmbed(nn.Module):
+    """ Image to Patch Embedding
+    """
+    def __init__(self, img_size=224, patch_size=16, in_chans=3, embed_dim=768):
+        super().__init__()
+        img_size = to_2tuple(img_size)
+        patch_size = to_2tuple(patch_size)
+        num_patches = (img_size[1] // patch_size[1]) * (img_size[0] // patch_size[0])
+        self.img_size = img_size
+        self.patch_size = patch_size
+        self.num_patches = num_patches
+        self.norm = nn.LayerNorm(embed_dim)
+        self.proj = nn.Conv2d(in_chans, embed_dim, kernel_size=patch_size, stride=patch_size)
+
+    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]})."
+        x = self.proj(x)
+        B, C, H, W = x.shape
+        x = x.flatten(2).transpose(1, 2)
+        x = self.norm(x)
+        x = x.reshape(B, H, W, -1).permute(0, 3, 1, 2).contiguous()
+        return x
+    
+    
+class UniFormer(nn.Module):
+    """ Vision Transformer
+    A PyTorch impl of : `An Image is Worth 16x16 Words: Transformers for Image Recognition at Scale`  -
+        https://arxiv.org/abs/2010.11929
+    """
+    def __init__(self, depth=[3, 4, 8, 3], img_size=224, in_chans=3, num_classes=1000, embed_dim=[64, 128, 320, 512],
+                 head_dim=64, mlp_ratio=4., qkv_bias=True, qk_scale=None, representation_size=None,
+                 drop_rate=0., attn_drop_rate=0., drop_path_rate=0., norm_layer=None, conv_stem=False):
+        """
+        Args:
+            depth (list): depth of each stage
+            img_size (int, tuple): input image size
+            in_chans (int): number of input channels
+            num_classes (int): number of classes for classification head
+            embed_dim (list): embedding dimension of each stage
+            head_dim (int): head dimension
+            mlp_ratio (int): ratio of mlp hidden dim to embedding dim
+            qkv_bias (bool): enable bias for qkv if True
+            qk_scale (float): override default qk scale of head_dim ** -0.5 if set
+            representation_size (Optional[int]): enable and set representation layer (pre-logits) to this value if set
+            drop_rate (float): dropout rate
+            attn_drop_rate (float): attention dropout rate
+            drop_path_rate (float): stochastic depth rate
+            norm_layer: (nn.Module): normalization layer
+            conv_stem: (bool): whether use overlapped patch stem
+        """
+        super().__init__()
+        self.num_classes = num_classes
+        self.num_features = self.embed_dim = embed_dim  # num_features for consistency with other models
+        norm_layer = norm_layer or partial(nn.LayerNorm, eps=1e-6) 
+        if conv_stem:
+            self.patch_embed1 = head_embedding(in_channels=in_chans, out_channels=embed_dim[0])
+            self.patch_embed2 = middle_embedding(in_channels=embed_dim[0], out_channels=embed_dim[1])
+            self.patch_embed3 = middle_embedding(in_channels=embed_dim[1], out_channels=embed_dim[2])
+            self.patch_embed4 = middle_embedding(in_channels=embed_dim[2], out_channels=embed_dim[3])
+        else:
+            self.patch_embed1 = PatchEmbed(
+                img_size=img_size, patch_size=4, in_chans=in_chans, embed_dim=embed_dim[0])
+            self.patch_embed2 = PatchEmbed(
+                img_size=img_size // 4, patch_size=2, in_chans=embed_dim[0], embed_dim=embed_dim[1])
+            self.patch_embed3 = PatchEmbed(
+                img_size=img_size // 8, patch_size=2, in_chans=embed_dim[1], embed_dim=embed_dim[2])
+            self.patch_embed4 = PatchEmbed(
+                img_size=img_size // 16, patch_size=2, in_chans=embed_dim[2], embed_dim=embed_dim[3])
+
+        self.pos_drop = nn.Dropout(p=drop_rate)
+        dpr = [x.item() for x in torch.linspace(0, drop_path_rate, sum(depth))]  # stochastic depth decay rule
+        num_heads = [dim // head_dim for dim in embed_dim]
+        self.blocks1 = nn.ModuleList([
+            CBlock(
+                dim=embed_dim[0], num_heads=num_heads[0], mlp_ratio=mlp_ratio, qkv_bias=qkv_bias, qk_scale=qk_scale,
+                drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[i], norm_layer=norm_layer)
+            for i in range(depth[0])])
+        self.blocks2 = nn.ModuleList([
+            CBlock(
+                dim=embed_dim[1], num_heads=num_heads[1], mlp_ratio=mlp_ratio, qkv_bias=qkv_bias, qk_scale=qk_scale,
+                drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[i+depth[0]], norm_layer=norm_layer)
+            for i in range(depth[1])])
+        self.blocks3 = nn.ModuleList([
+            SABlock(
+                dim=embed_dim[2], num_heads=num_heads[2], mlp_ratio=mlp_ratio, qkv_bias=qkv_bias, qk_scale=qk_scale,
+                drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[i+depth[0]+depth[1]], norm_layer=norm_layer)
+            for i in range(depth[2])])
+        self.blocks4 = nn.ModuleList([
+            SABlock(
+                dim=embed_dim[3], num_heads=num_heads[3], mlp_ratio=mlp_ratio, qkv_bias=qkv_bias, qk_scale=qk_scale,
+                drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[i+depth[0]+depth[1]+depth[2]], norm_layer=norm_layer)
+        for i in range(depth[3])])
+        self.norm = nn.BatchNorm2d(embed_dim[-1])
+        
+        # Representation layer
+        if representation_size:
+            self.num_features = representation_size
+            self.pre_logits = nn.Sequential(OrderedDict([
+                ('fc', nn.Linear(embed_dim, representation_size)),
+                ('act', nn.Tanh())
+            ]))
+        else:
+            self.pre_logits = nn.Identity()
+
+        # Classifier head
+        self.head = nn.Linear(embed_dim[-1], num_classes) if num_classes > 0 else nn.Identity()
+        
+        self.apply(self._init_weights)
+
+    def _init_weights(self, m):
+        if isinstance(m, nn.Linear):
+            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 {'pos_embed', 'cls_token'}
+
+    def get_classifier(self):
+        return self.head
+
+    def reset_classifier(self, num_classes, global_pool=''):
+        self.num_classes = num_classes
+        self.head = nn.Linear(self.embed_dim, num_classes) if num_classes > 0 else nn.Identity()
+
+    def forward_features(self, x):
+        B = x.shape[0]
+        x = self.patch_embed1(x)
+        x = self.pos_drop(x)
+        for blk in self.blocks1:
+            x = blk(x)
+        x = self.patch_embed2(x)
+        for blk in self.blocks2:
+            x = blk(x)
+        x = self.patch_embed3(x)
+        for blk in self.blocks3:
+            x = blk(x)
+        x = self.patch_embed4(x)
+        for blk in self.blocks4:
+            x = blk(x)
+        x = self.norm(x)
+        x = self.pre_logits(x)
+        return x
+
+    def forward(self, x):
+        x = self.forward_features(x)
+        x = x.flatten(2).mean(-1)
+        x = self.head(x)
+        return x
+
+
+@register_model
+def uniformer_small(pretrained=True, **kwargs):
+    model = UniFormer(
+        depth=[3, 4, 8, 3],
+        embed_dim=[64, 128, 320, 512], head_dim=64, mlp_ratio=4, qkv_bias=True,
+        norm_layer=partial(nn.LayerNorm, eps=1e-6), **kwargs)
+    model.default_cfg = _cfg()
+    return model
+
+
+@register_model
+def uniformer_small_plus(pretrained=True, **kwargs):
+    model = UniFormer(
+        depth=[3, 5, 9, 3], conv_stem=True,
+        embed_dim=[64, 128, 320, 512], head_dim=64, mlp_ratio=4, qkv_bias=True,
+        norm_layer=partial(nn.LayerNorm, eps=1e-6), **kwargs)
+    model.default_cfg = _cfg()
+    return model
+
+
+@register_model
+def uniformer_base(pretrained=True, **kwargs):
+    model = UniFormer(
+        depth=[5, 8, 20, 7],
+        embed_dim=[64, 128, 320, 512], head_dim=64, mlp_ratio=4, qkv_bias=True,
+        norm_layer=partial(nn.LayerNorm, eps=1e-6), **kwargs)
+    model.default_cfg = _cfg()
+    return model
+
+
+@register_model
+def uniformer_base_ls(pretrained=True, **kwargs):
+    global layer_scale
+    layer_scale = True
+    model = UniFormer(
+        depth=[5, 8, 20, 7],
+        embed_dim=[64, 128, 320, 512], head_dim=64, mlp_ratio=4, qkv_bias=True,
+        norm_layer=partial(nn.LayerNorm, eps=1e-6), **kwargs)
+    model.default_cfg = _cfg()
+    return model