Implement Eca modules

implement ECA module by
1. adopting original eca_module.py into models folder
2. adding use_eca layer besides every instance of SE layer

.gitignore

@@ -105,3 +105,4 @@ venv.bak/
 *.pth
 *.gz
 Untitled.ipynb
+Testing notebook.ipynb

timm/models/eca_module.py

@@ -0,0 +1,110 @@
+'''
+ECA module from ECAnet 
+original paper: ECA-Net: Efficient Channel Attention for Deep Convolutional Neural Networks
+https://arxiv.org/abs/1910.03151
+
+https://github.com/BangguWu/ECANet
+original ECA model borrowed from original github
+modified circular ECA implementation and 
+adoptation for use in pytorch image models package
+by Chris Ha https://github.com/VRandme
+
+MIT License
+
+Copyright (c) 2019 BangguWu, Qilong Wang 
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+'''
+import torch
+from torch import nn
+from torch.nn.parameter import Parameter
+
+
+class eca_layer(nn.Module):
+    """Constructs a ECA module.
+
+    Args:
+        channel: Number of channels of the input feature map
+        k_size: Adaptive selection of kernel size
+    """
+    def __init__(self, channel, k_size=3):
+        super(eca_layer, self).__init__()
+        assert k_size % 2 == 1
+        self.avg_pool = nn.AdaptiveAvgPool2d(1)
+        self.conv = nn.Conv1d(1, 1, kernel_size=k_size, padding=(k_size - 1) // 2, bias=False) 
+        self.sigmoid = nn.Sigmoid()
+
+    def forward(self, x):
+        # x: input features with shape [b, c, h, w]
+        b, c, h, w = x.size()
+
+        # feature descriptor on the global spatial information
+        y = self.avg_pool(x)
+
+        # Two different branches of ECA module
+        y = self.conv(y.squeeze(-1).transpose(-1, -2)).transpose(-1, -2).unsqueeze(-1)
+
+        # Multi-scale information fusion
+        y = self.sigmoid(y)
+
+        return x * y.expand_as(x)
+
+class ceca_layer(nn.Module):
+    """Constructs a circular ECA module.
+    the primary difference is that the conv uses a circular padding rather than zero padding.
+    This is because unlike images, the channels themselves do not have inherent ordering nor 
+    locality. Although this module in essence, applies such an assumption, it is unnecessary
+    to limit the channels on either "edge" from being circularly adapted to each other.
+    This will fundamentally increase connectivity and possibly increase performance metrics
+    (accuracy, robustness), without signficantly impacting resource metrics 
+    (parameter size, throughput,latency, etc)
+
+
+    Args:
+        channel: Number of channels of the input feature map
+        k_size: Adaptive selection of kernel size
+    """
+    def __init__(self, channel, k_size=3):
+        super(ceca_layer, self).__init__()
+        assert k_size % 2 == 1
+        self.avg_pool = nn.AdaptiveAvgPool2d(1)
+        #pytorch circular padding mode is bugged as of pytorch 1.4
+        # see https://github.com/pytorch/pytorch/pull/17240
+        #implement manual circular padding
+        self.conv = nn.Conv1d(1, 1, kernel_size=k_size, padding = 0, bias=False)
+        self.padding = (k_size - 1) // 2
+        self.sigmoid = nn.Sigmoid()
+
+    def forward(self, x):
+        # x: input features with shape [b, c, h, w]
+        b, c, h, w = x.size()
+        # feature descriptor on the global spatial information
+        y = self.avg_pool(x)
+        
+        #manually implement circular padding
+        y = torch.cat((y[:,:self.padding,:,:], y, y[:,-self.padding:,:,:]),dim=1)
+        
+
+        # Two different branches of ECA module
+        y = self.conv(y.squeeze(-1).transpose(-1, -2)).transpose(-1, -2).unsqueeze(-1)
+
+        # Multi-scale information fusion
+        y = self.sigmoid(y)
+
+        return x * y.expand_as(x)

timm/models/resnet.py

@@ -14,6 +14,7 @@ import torch.nn.functional as F
 from .registry import register_model
 from .helpers import load_pretrained
 from .adaptive_avgmax_pool import SelectAdaptivePool2d
+from .eca_module import eca_layer
 from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
 
 
@@ -100,6 +101,10 @@ default_cfgs = {
     'seresnext26tn_32x4d': _cfg(
         url='https://github.com/rwightman/pytorch-image-models/releases/download/v0.1-weights/seresnext26tn_32x4d-569cb627.pth',
         interpolation='bicubic'),
+    'ecaresnext26tn_32x4d': _cfg(
+        url='',
+        interpolation='bicubic'),
+    
 }
 
 
@@ -132,7 +137,7 @@ class BasicBlock(nn.Module):
     expansion = 1
 
     def __init__(self, inplanes, planes, stride=1, downsample=None,
-                 cardinality=1, base_width=64, use_se=False,
+                 cardinality=1, base_width=64, use_se=False, use_eca = False,
                  reduce_first=1, dilation=1, previous_dilation=1, act_layer=nn.ReLU, norm_layer=nn.BatchNorm2d):
         super(BasicBlock, self).__init__()
 
@@ -150,7 +155,10 @@ class BasicBlock(nn.Module):
             first_planes, outplanes, kernel_size=3, padding=previous_dilation,
             dilation=previous_dilation, bias=False)
         self.bn2 = norm_layer(outplanes)
+
         self.se = SEModule(outplanes, planes // 4) if use_se else None
+        self.eca = eca_layer(outplanes) if use_eca else None
+
         self.act2 = act_layer(inplace=True)
         self.downsample = downsample
         self.stride = stride
@@ -167,6 +175,8 @@ class BasicBlock(nn.Module):
 
         if self.se is not None:
             out = self.se(out)
+        if self.eca is not None:
+            out = self.eca(out)
 
         if self.downsample is not None:
             residual = self.downsample(x)
@@ -182,7 +192,7 @@ class Bottleneck(nn.Module):
     expansion = 4
 
     def __init__(self, inplanes, planes, stride=1, downsample=None,
-                 cardinality=1, base_width=64, use_se=False,
+                 cardinality=1, base_width=64, use_se=False, use_eca=False,
                  reduce_first=1, dilation=1, previous_dilation=1, act_layer=nn.ReLU, norm_layer=nn.BatchNorm2d):
         super(Bottleneck, self).__init__()
 
@@ -200,7 +210,10 @@ class Bottleneck(nn.Module):
         self.act2 = act_layer(inplace=True)
         self.conv3 = nn.Conv2d(width, outplanes, kernel_size=1, bias=False)
         self.bn3 = norm_layer(outplanes)
+
         self.se = SEModule(outplanes, planes // 4) if use_se else None
+        self.eca = eca_layer(outplanes) if use_eca else None
+    
         self.act3 = act_layer(inplace=True)
         self.downsample = downsample
         self.stride = stride
@@ -222,6 +235,8 @@ class Bottleneck(nn.Module):
 
         if self.se is not None:
             out = self.se(out)
+        if self.eca is not None:
+            out = self.eca(out)
 
         if self.downsample is not None:
             residual = self.downsample(x)
@@ -275,6 +290,8 @@ class ResNet(nn.Module):
         Number of input (color) channels.
     use_se : bool, default False
         Enable Squeeze-Excitation module in blocks
+    use_eca : bool, default False
+        Enable ECA module in blocks
     cardinality : int, default 1
         Number of convolution groups for 3x3 conv in Bottleneck.
     base_width : int, default 64
@@ -303,7 +320,7 @@ class ResNet(nn.Module):
     global_pool : str, default 'avg'
         Global pooling type. One of 'avg', 'max', 'avgmax', 'catavgmax'
     """
-    def __init__(self, block, layers, num_classes=1000, in_chans=3, use_se=False,
+    def __init__(self, block, layers, num_classes=1000, in_chans=3, use_se=False, use_eca=False,
                  cardinality=1, base_width=64, stem_width=64, stem_type='',
                  block_reduce_first=1, down_kernel_size=1, avg_down=False, output_stride=32,
                  act_layer=nn.ReLU, norm_layer=nn.BatchNorm2d, drop_rate=0.0, global_pool='avg',
@@ -350,7 +367,7 @@ class ResNet(nn.Module):
             assert output_stride == 32
         llargs = list(zip(channels, layers, strides, dilations))
         lkwargs = dict(
-            use_se=use_se, reduce_first=block_reduce_first, act_layer=act_layer, norm_layer=norm_layer,
+            use_se=use_se, use_eca=use_eca, reduce_first=block_reduce_first, act_layer=act_layer, norm_layer=norm_layer,
             avg_down=avg_down, down_kernel_size=down_kernel_size, **block_args)
         self.layer1 = self._make_layer(block, *llargs[0], **lkwargs)
         self.layer2 = self._make_layer(block, *llargs[1], **lkwargs)
@@ -375,7 +392,7 @@ class ResNet(nn.Module):
                 nn.init.constant_(m.bias, 0.)
 
     def _make_layer(self, block, planes, blocks, stride=1, dilation=1, reduce_first=1,
-                    use_se=False, avg_down=False, down_kernel_size=1, **kwargs):
+                    use_se=False, use_eca=False,avg_down=False, down_kernel_size=1, **kwargs):
         norm_layer = kwargs.get('norm_layer')
         downsample = None
         down_kernel_size = 1 if stride == 1 and dilation == 1 else down_kernel_size
@@ -396,7 +413,7 @@ class ResNet(nn.Module):
         first_dilation = 1 if dilation in (1, 2) else 2
         bkwargs = dict(
             cardinality=self.cardinality, base_width=self.base_width, reduce_first=reduce_first,
-            use_se=use_se, **kwargs)
+            use_se=use_se, use_eca=use_eca, **kwargs)
         layers = [block(
             self.inplanes, planes, stride, downsample, dilation=first_dilation, previous_dilation=dilation, **bkwargs)]
         self.inplanes = planes * block.expansion
@@ -944,3 +961,20 @@ def seresnext26tn_32x4d(pretrained=False, num_classes=1000, in_chans=3, **kwargs
     if pretrained:
         load_pretrained(model, default_cfg, num_classes, in_chans)
     return model
+
+@register_model
+def ecaresnext26tn_32x4d(pretrained=False, num_classes=1000, in_chans=3, **kwargs):
+    """Constructs a eca-ResNeXt-26-TN model.
+    This is technically a 28 layer ResNet, like a 'D' bag-of-tricks model but with tiered 24, 32, 64 channels
+    in the deep stem. The channel number of the middle stem conv is narrower than the 'T' variant.
+    this model replaces SE module with the ECA module
+    """
+    default_cfg = default_cfgs['ecaresnext26tn_32x4d']
+    model = ResNet(
+        Bottleneck, [2, 2, 2, 2], cardinality=32, base_width=4,
+        stem_width=32, stem_type='deep_tiered_narrow', avg_down=True, use_eca=True,
+        num_classes=num_classes, in_chans=in_chans, **kwargs)
+    model.default_cfg = default_cfg
+    if pretrained:
+        load_pretrained(model, default_cfg, num_classes, in_chans)
+    return model