Fixup byoanet configs to pass unit tests. Add swin_attn and swinnet26t model for testing.

timm/models/byoanet.py

@@ -35,7 +35,7 @@ __all__ = ['ByoaNet']
 def _cfg(url='', **kwargs):
     return {
         'url': url, 'num_classes': 1000, 'input_size': (3, 224, 224), 'pool_size': (7, 7),
-        'crop_pct': 0.875, 'interpolation': 'bilinear',
+        'crop_pct': 0.875, 'interpolation': 'bicubic',
         'mean': IMAGENET_DEFAULT_MEAN, 'std': IMAGENET_DEFAULT_STD,
         'first_conv': 'stem.conv1.conv', 'classifier': 'head.fc',
         'fixed_input_size': False, 'min_input_size': (3, 224, 224),
@@ -45,17 +45,19 @@ def _cfg(url='', **kwargs):
 
 default_cfgs = {
     # GPU-Efficient (ResNet) weights
-    'botnet26t_256': _cfg(url='', fixed_input_size=True, input_size=(3, 256, 256)),
+    'botnet26t_256': _cfg(url='', fixed_input_size=True, input_size=(3, 256, 256), pool_size=(8, 8)),
     'botnet50t_224': _cfg(url='', fixed_input_size=True),
     'botnet50t_c4c5_224': _cfg(url='', fixed_input_size=True),
 
     'halonet_h1': _cfg(url='', input_size=(3, 256, 256), pool_size=(8, 8), min_input_size=(3, 256, 256)),
     'halonet_h1_c4c5': _cfg(url='', input_size=(3, 256, 256), pool_size=(8, 8), min_input_size=(3, 256, 256)),
-    'halonet26t': _cfg(url='', input_size=(3, 256, 256)),
+    'halonet26t': _cfg(url='', input_size=(3, 256, 256), pool_size=(8, 8), min_input_size=(3, 256, 256)),
-    'halonet50t': _cfg(url=''),
+    'halonet50t': _cfg(url='', min_input_size=(3, 224, 224)),
 
-    'lambda_resnet26t': _cfg(url='', min_input_size=(3, 128, 128), input_size=(3, 256, 256)),
+    'lambda_resnet26t': _cfg(url='', min_input_size=(3, 128, 128), input_size=(3, 256, 256), pool_size=(8, 8)),
     'lambda_resnet50t': _cfg(url='', min_input_size=(3, 128, 128)),
+
+    'swinnet26t_256': _cfg(url='', fixed_input_size=True, input_size=(3, 256, 256), pool_size=(8, 8)),
 }
 
 
@@ -95,10 +97,10 @@ model_cfgs = dict(
 
     botnet26t=ByoaCfg(
         blocks=(
-            ByoaBlocksCfg(type='bottle', d=3, c=256, s=2, gs=0, br=0.25),
+            ByoaBlocksCfg(type='bottle', d=3, c=256, s=1, gs=0, br=0.25),
             ByoaBlocksCfg(type='bottle', d=4, c=512, s=2, gs=0, br=0.25),
             interleave_attn(types=('bottle', 'self_attn'), every=1, d=2, c=1024, s=2, gs=0, br=0.25),
-            ByoaBlocksCfg(type='self_attn', d=3, c=2048, s=1, gs=0, br=0.25),
+            ByoaBlocksCfg(type='self_attn', d=3, c=2048, s=2, gs=0, br=0.25),
         ),
         stem_chs=64,
         stem_type='tiered',
@@ -230,6 +232,22 @@ model_cfgs = dict(
         self_attn_layer='lambda',
         self_attn_kwargs=dict()
     ),
+
+    swinnet26t=ByoaCfg(
+        blocks=(
+            ByoaBlocksCfg(type='bottle', d=3, c=256, s=1, gs=0, br=0.25),
+            ByoaBlocksCfg(type='bottle', d=4, c=512, s=2, gs=0, br=0.25),
+            interleave_attn(types=('bottle', 'self_attn'), every=1, d=2, c=1024, s=2, gs=0, br=0.25),
+            ByoaBlocksCfg(type='self_attn', d=3, c=2048, s=2, gs=0, br=0.25),
+        ),
+        stem_chs=64,
+        stem_type='tiered',
+        stem_pool='maxpool',
+        num_features=0,
+        self_attn_layer='swin',
+        self_attn_fixed_size=True,
+        self_attn_kwargs=dict(win_size=8)
+    ),
 )
 
 
@@ -452,3 +470,11 @@ def lambda_resnet50t(pretrained=False, **kwargs):
     """ Lambda-ResNet-50T. Lambda layers in one C4 stage and all C5.
     """
     return _create_byoanet('lambda_resnet50t', pretrained=pretrained, **kwargs)
+
+
+@register_model
+def swinnet26t_256(pretrained=False, **kwargs):
+    """
+    """
+    kwargs.setdefault('img_size', 256)
+    return _create_byoanet('swinnet26t_256', 'swinnet26t', pretrained=pretrained, **kwargs)

timm/models/layers/create_self_attn.py

@@ -1,6 +1,7 @@
 from .bottleneck_attn import BottleneckAttn
 from .halo_attn import HaloAttn
 from .lambda_layer import LambdaLayer
+from .swin_attn import WindowAttention
 
 
 def get_self_attn(attn_type):
@@ -10,6 +11,10 @@ def get_self_attn(attn_type):
         return HaloAttn
     elif attn_type == 'lambda':
         return LambdaLayer
+    elif attn_type == 'swin':
+        return WindowAttention
+    else:
+        assert False, f"Unknown attn type ({attn_type})"
 
 
 def create_self_attn(attn_type, dim, stride=1, **kwargs):

timm/models/layers/swin_attn.py

@@ -0,0 +1,178 @@
+""" Shifted Window Attn
+
+This is a WIP experiment to apply windowed attention from the Swin Transformer
+to a stand-alone module for use as an attn block in conv nets.
+
+Based on original swin window code at https://github.com/microsoft/Swin-Transformer
+Swin Transformer paper: https://arxiv.org/pdf/2103.14030.pdf
+"""
+from typing import Optional
+
+import torch
+import torch.nn as nn
+
+from .drop import DropPath
+from .helpers import to_2tuple
+from .weight_init import trunc_normal_
+
+
+def window_partition(x, win_size: int):
+    """
+    Args:
+        x: (B, H, W, C)
+        win_size (int): window size
+
+    Returns:
+        windows: (num_windows*B, window_size, window_size, C)
+    """
+    B, H, W, C = x.shape
+    x = x.view(B, H // win_size, win_size, W // win_size, win_size, C)
+    windows = x.permute(0, 1, 3, 2, 4, 5).contiguous().view(-1, win_size, win_size, C)
+    return windows
+
+
+def window_reverse(windows, win_size: int, H: int, W: int):
+    """
+    Args:
+        windows: (num_windows*B, window_size, window_size, C)
+        win_size (int): Window size
+        H (int): Height of image
+        W (int): Width of image
+
+    Returns:
+        x: (B, H, W, C)
+    """
+    B = int(windows.shape[0] / (H * W / win_size / win_size))
+    x = windows.view(B, H // win_size, W // win_size, win_size, win_size, -1)
+    x = x.permute(0, 1, 3, 2, 4, 5).contiguous().view(B, H, W, -1)
+    return x
+
+
+class WindowAttention(nn.Module):
+    r""" Window based multi-head self attention (W-MSA) module with relative position bias.
+    It supports both of shifted and non-shifted window.
+
+    Args:
+        dim (int): Number of input channels.
+        win_size (int): The height and width of the window.
+        num_heads (int): Number of attention heads.
+        qkv_bias (bool, optional):  If True, add a learnable bias to query, key, value. Default: True
+        attn_drop (float, optional): Dropout ratio of attention weight. Default: 0.0
+    """
+
+    def __init__(
+            self, dim, dim_out=None, feat_size=None, stride=1, win_size=8, shift_size=None, num_heads=8,
+            qkv_bias=True, attn_drop=0.):
+
+        super().__init__()
+        self.dim_out = dim_out or dim
+        self.feat_size = to_2tuple(feat_size)
+        self.win_size = win_size
+        self.shift_size = shift_size or win_size // 2
+        if min(self.feat_size) <= win_size:
+            # if window size is larger than input resolution, we don't partition windows
+            self.shift_size = 0
+            self.win_size = min(self.feat_size)
+        assert 0 <= self.shift_size < self.win_size, "shift_size must in 0-window_size"
+        self.num_heads = num_heads
+        head_dim = self.dim_out // num_heads
+        self.scale = head_dim ** -0.5
+
+        if self.shift_size > 0:
+            # calculate attention mask for SW-MSA
+            H, W = self.feat_size
+            img_mask = torch.zeros((1, H, W, 1))  # 1 H W 1
+            h_slices = (
+                slice(0, -self.win_size),
+                slice(-self.win_size, -self.shift_size),
+                slice(-self.shift_size, None))
+            w_slices = (
+                slice(0, -self.win_size),
+                slice(-self.win_size, -self.shift_size),
+                slice(-self.shift_size, None))
+            cnt = 0
+            for h in h_slices:
+                for w in w_slices:
+                    img_mask[:, h, w, :] = cnt
+                    cnt += 1
+            mask_windows = window_partition(img_mask, self.win_size)  # num_win, window_size, window_size, 1
+            mask_windows = mask_windows.view(-1, self.win_size * self.win_size)
+            attn_mask = mask_windows.unsqueeze(1) - mask_windows.unsqueeze(2)
+            attn_mask = attn_mask.masked_fill(attn_mask != 0, float(-100.0)).masked_fill(attn_mask == 0, float(0.0))
+        else:
+            attn_mask = None
+        self.register_buffer("attn_mask", attn_mask)
+
+        # define a parameter table of relative position bias
+        self.relative_position_bias_table = nn.Parameter(
+            # 2 * Wh - 1 * 2 * Ww - 1, nH
+            torch.zeros((2 * self.win_size - 1) * (2 * self.win_size - 1), num_heads))
+
+        # get pair-wise relative position index for each token inside the window
+        coords_h = torch.arange(self.win_size)
+        coords_w = torch.arange(self.win_size)
+        coords = torch.stack(torch.meshgrid([coords_h, coords_w]))  # 2, Wh, Ww
+        coords_flatten = torch.flatten(coords, 1)  # 2, Wh*Ww
+        relative_coords = coords_flatten[:, :, None] - coords_flatten[:, None, :]  # 2, Wh*Ww, Wh*Ww
+        relative_coords = relative_coords.permute(1, 2, 0).contiguous()  # Wh*Ww, Wh*Ww, 2
+        relative_coords[:, :, 0] += self.win_size - 1  # shift to start from 0
+        relative_coords[:, :, 1] += self.win_size - 1
+        relative_coords[:, :, 0] *= 2 * self.win_size - 1
+        relative_position_index = relative_coords.sum(-1)  # Wh*Ww, Wh*Ww
+        self.register_buffer("relative_position_index", relative_position_index)
+        trunc_normal_(self.relative_position_bias_table, std=.02)
+
+        self.qkv = nn.Linear(dim, self.dim_out * 3, bias=qkv_bias)
+        self.attn_drop = nn.Dropout(attn_drop)
+        self.softmax = nn.Softmax(dim=-1)
+        self.pool = nn.AvgPool2d(2, 2) if stride == 2 else nn.Identity()
+
+    def forward(self, x):
+        B, C, H, W = x.shape
+        x = x.permute(0, 2, 3, 1)
+
+        # cyclic shift
+        if self.shift_size > 0:
+            shifted_x = torch.roll(x, shifts=(-self.shift_size, -self.shift_size), dims=(1, 2))
+        else:
+            shifted_x = x
+
+        # partition windows
+        win_size_sq = self.win_size * self.win_size
+        x_windows = window_partition(shifted_x, self.win_size)  # num_win * B, window_size, window_size, C
+        x_windows = x_windows.view(-1, win_size_sq, C)  # num_win * B, window_size*window_size, C
+        BW, N, _ = x_windows.shape
+
+        qkv = self.qkv(x_windows)
+        qkv = qkv.reshape(BW, N, 3, self.num_heads, self.dim_out // self.num_heads).permute(2, 0, 3, 1, 4)
+        q, k, v = qkv[0], qkv[1], qkv[2]
+        q = q * self.scale
+        attn = (q @ k.transpose(-2, -1))
+
+        relative_position_bias = self.relative_position_bias_table[
+            self.relative_position_index.view(-1)].view(win_size_sq, win_size_sq, -1)
+        relative_position_bias = relative_position_bias.permute(2, 0, 1).contiguous()  # nH, Wh * Ww, Wh * Ww
+        attn = attn + relative_position_bias.unsqueeze(0)
+        if self.attn_mask is not None:
+            num_win = self.attn_mask.shape[0]
+            attn = attn.view(B, num_win, self.num_heads, N, N) + self.attn_mask.unsqueeze(1).unsqueeze(0)
+            attn = attn.view(-1, self.num_heads, N, N)
+        attn = self.softmax(attn)
+        attn = self.attn_drop(attn)
+
+        x = (attn @ v).transpose(1, 2).reshape(BW, N, self.dim_out)
+
+        # merge windows
+        x = x.view(-1, self.win_size, self.win_size, self.dim_out)
+        shifted_x = window_reverse(x, self.win_size, H, W)  # B H' W' C
+
+        # reverse cyclic shift
+        if self.shift_size > 0:
+            x = torch.roll(shifted_x, shifts=(self.shift_size, self.shift_size), dims=(1, 2))
+        else:
+            x = shifted_x
+        x = x.view(B, H, W, self.dim_out).permute(0, 3, 1, 2)
+        x = self.pool(x)
+        return x
+
+