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import torch.nn as nn |
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import torch.utils.checkpoint as cp |
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from mmcv.cnn import ConvModule |
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from mmcv.cnn.bricks import DropPath |
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from mmengine.model import BaseModule |
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from .se_layer import SELayer |
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class InvertedResidual(BaseModule): |
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"""Inverted Residual Block. |
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Args: |
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in_channels (int): The input channels of this Module. |
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out_channels (int): The output channels of this Module. |
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mid_channels (int): The input channels of the depthwise convolution. |
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kernel_size (int): The kernel size of the depthwise convolution. |
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Default: 3. |
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stride (int): The stride of the depthwise convolution. Default: 1. |
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se_cfg (dict): Config dict for se layer. Default: None, which means no |
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se layer. |
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with_expand_conv (bool): Use expand conv or not. If set False, |
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mid_channels must be the same with in_channels. |
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Default: True. |
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conv_cfg (dict): Config dict for convolution layer. Default: None, |
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which means using conv2d. |
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norm_cfg (dict): Config dict for normalization layer. |
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Default: dict(type='BN'). |
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act_cfg (dict): Config dict for activation layer. |
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Default: dict(type='ReLU'). |
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drop_path_rate (float): stochastic depth rate. Defaults to 0. |
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with_cp (bool): Use checkpoint or not. Using checkpoint will save some |
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memory while slowing down the training speed. Default: False. |
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init_cfg (dict or list[dict], optional): Initialization config dict. |
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Default: None |
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Returns: |
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Tensor: The output tensor. |
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""" |
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def __init__(self, |
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in_channels, |
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out_channels, |
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mid_channels, |
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kernel_size=3, |
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stride=1, |
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se_cfg=None, |
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with_expand_conv=True, |
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conv_cfg=None, |
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norm_cfg=dict(type='BN'), |
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act_cfg=dict(type='ReLU'), |
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drop_path_rate=0., |
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with_cp=False, |
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init_cfg=None): |
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super(InvertedResidual, self).__init__(init_cfg) |
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self.with_res_shortcut = (stride == 1 and in_channels == out_channels) |
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self.with_cp = with_cp |
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self.drop_path = DropPath( |
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drop_path_rate) if drop_path_rate > 0 else nn.Identity() |
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self.with_se = se_cfg is not None |
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self.with_expand_conv = with_expand_conv |
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if self.with_se: |
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assert isinstance(se_cfg, dict) |
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if not self.with_expand_conv: |
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assert mid_channels == in_channels |
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if self.with_expand_conv: |
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self.expand_conv = ConvModule( |
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in_channels=in_channels, |
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out_channels=mid_channels, |
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kernel_size=1, |
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stride=1, |
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padding=0, |
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conv_cfg=conv_cfg, |
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norm_cfg=norm_cfg, |
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act_cfg=act_cfg) |
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self.depthwise_conv = ConvModule( |
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in_channels=mid_channels, |
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out_channels=mid_channels, |
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kernel_size=kernel_size, |
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stride=stride, |
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padding=kernel_size // 2, |
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groups=mid_channels, |
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conv_cfg=conv_cfg, |
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norm_cfg=norm_cfg, |
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act_cfg=act_cfg) |
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if self.with_se: |
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self.se = SELayer(**se_cfg) |
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self.linear_conv = ConvModule( |
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in_channels=mid_channels, |
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out_channels=out_channels, |
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kernel_size=1, |
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stride=1, |
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padding=0, |
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conv_cfg=conv_cfg, |
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norm_cfg=norm_cfg, |
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act_cfg=None) |
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def forward(self, x): |
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def _inner_forward(x): |
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out = x |
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if self.with_expand_conv: |
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out = self.expand_conv(out) |
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out = self.depthwise_conv(out) |
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if self.with_se: |
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out = self.se(out) |
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out = self.linear_conv(out) |
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if self.with_res_shortcut: |
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return x + self.drop_path(out) |
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else: |
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return out |
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if self.with_cp and x.requires_grad: |
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out = cp.checkpoint(_inner_forward, x) |
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else: |
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out = _inner_forward(x) |
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return out |
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