361 lines
11 KiB
Python
361 lines
11 KiB
Python
import copy
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import math
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from collections import OrderedDict
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from functools import partial
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from typing import Callable, Optional
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import torch
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import torch.nn as nn
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from torch import Tensor
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from torch.nn import functional as F
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def _make_divisible(ch, divisor=8, min_ch=None):
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if min_ch is None:
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min_ch = divisor
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new_ch = max(min_ch, int(ch + divisor / 2) // divisor * divisor)
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if new_ch < 0.9 * ch:
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new_ch += divisor
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return new_ch
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def drop_path(x, drop_prob: float = 0.0, training: bool = False):
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if drop_prob == 0.0 or not training:
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return x
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keep_prob = 1 - drop_prob
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shape = (x.shape[0],) + (1,) * (
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x.ndim - 1
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) # work with diff dim tensors, not just 2D ConvNets
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random_tensor = keep_prob + torch.rand(shape, dtype=x.dtype, device=x.device)
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random_tensor.floor_() # binarize
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output = x.div(keep_prob) * random_tensor
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return output
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class DropPath(nn.Module):
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def __init__(self, drop_prob=None):
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super(DropPath, self).__init__()
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self.drop_prob = drop_prob
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def forward(self, x):
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return drop_path(x, self.drop_prob, self.training)
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class ConvBNActivation(nn.Sequential):
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def __init__(
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self,
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in_planes: int,
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out_planes: int,
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kernel_size: int = 3,
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stride: int = 1,
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groups: int = 1,
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norm_layer: Optional[Callable[..., nn.Module]] = None,
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activation_layer: Optional[Callable[..., nn.Module]] = None,
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):
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padding = (kernel_size - 1) // 2
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if norm_layer is None:
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norm_layer = nn.BatchNorm2d
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if activation_layer is None:
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activation_layer = nn.SiLU # alias Swish (torch>=1.7)
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super(ConvBNActivation, self).__init__(
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nn.Conv2d(
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in_channels=in_planes,
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out_channels=out_planes,
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kernel_size=kernel_size,
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stride=stride,
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padding=padding,
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groups=groups,
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bias=False,
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),
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norm_layer(out_planes),
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activation_layer(),
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)
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class SqueezeExcitation(nn.Module):
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def __init__(self, input_c: int, expand_c: int, squeeze_factor: int = 4):
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super(SqueezeExcitation, self).__init__()
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squeeze_c = input_c // squeeze_factor
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self.fc1 = nn.Conv2d(expand_c, squeeze_c, 1)
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self.ac1 = nn.SiLU()
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self.fc2 = nn.Conv2d(squeeze_c, expand_c, 1)
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self.ac2 = nn.Sigmoid()
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def forward(self, x: Tensor) -> Tensor:
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scale = F.adaptive_avg_pool2d(x, output_size=(1, 1))
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scale = self.fc1(scale)
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scale = self.ac1(scale)
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scale = self.fc2(scale)
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scale = self.ac2(scale)
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return scale * x
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class InvertedResidualConfig:
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def __init__(
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self,
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kernel: int,
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input_c: int,
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out_c: int,
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expanded_ratio: int,
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stride: int,
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use_se: bool,
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drop_rate: float,
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index: str,
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width_coefficient: float,
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):
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self.input_c = self.adjust_channels(input_c, width_coefficient)
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self.kernel = kernel
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self.expanded_c = self.input_c * expanded_ratio
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self.out_c = self.adjust_channels(out_c, width_coefficient)
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self.use_se = use_se
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self.stride = stride
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self.drop_rate = drop_rate
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self.index = index
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@staticmethod
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def adjust_channels(channels: int, width_coefficient: float):
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return _make_divisible(channels * width_coefficient, 8)
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class InvertedResidual(nn.Module):
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def __init__(
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self, cnf: InvertedResidualConfig, norm_layer: Callable[..., nn.Module]
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):
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super(InvertedResidual, self).__init__()
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if cnf.stride not in [1, 2]:
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raise ValueError("illegal stride value.")
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self.use_res_connect = cnf.stride == 1 and cnf.input_c == cnf.out_c
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layers = OrderedDict()
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activation_layer = nn.SiLU
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if cnf.expanded_c != cnf.input_c:
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layers.update(
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{
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"expand_conv": ConvBNActivation(
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cnf.input_c,
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cnf.expanded_c,
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kernel_size=1,
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norm_layer=norm_layer,
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activation_layer=activation_layer,
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)
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}
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)
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layers.update(
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{
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"dwconv": ConvBNActivation(
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cnf.expanded_c,
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cnf.expanded_c,
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kernel_size=cnf.kernel,
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stride=cnf.stride,
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groups=cnf.expanded_c,
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norm_layer=norm_layer,
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activation_layer=activation_layer,
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)
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}
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)
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if cnf.use_se:
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layers.update({"se": SqueezeExcitation(cnf.input_c, cnf.expanded_c)})
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layers.update(
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{
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"project_conv": ConvBNActivation(
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cnf.expanded_c,
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cnf.out_c,
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kernel_size=1,
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norm_layer=norm_layer,
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activation_layer=nn.Identity,
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)
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}
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)
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self.block = nn.Sequential(layers)
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self.out_channels = cnf.out_c
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self.is_strided = cnf.stride > 1
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if self.use_res_connect and cnf.drop_rate > 0:
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self.dropout = DropPath(cnf.drop_rate)
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else:
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self.dropout = nn.Identity()
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def forward(self, x: Tensor) -> Tensor:
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result = self.block(x)
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result = self.dropout(result)
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if self.use_res_connect:
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result += x
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return result
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class EfficientNet(nn.Module):
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def __init__(
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self,
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width_coefficient: float,
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depth_coefficient: float,
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num_classes: int = 1000,
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dropout_rate: float = 0.2,
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drop_connect_rate: float = 0.2,
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block: Optional[Callable[..., nn.Module]] = None,
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norm_layer: Optional[Callable[..., nn.Module]] = None,
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):
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super(EfficientNet, self).__init__()
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default_cnf = [
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[3, 32, 16, 1, 1, True, drop_connect_rate, 1],
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[3, 16, 24, 6, 2, True, drop_connect_rate, 2],
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[5, 24, 40, 6, 2, True, drop_connect_rate, 2],
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[3, 40, 80, 6, 2, True, drop_connect_rate, 3],
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[5, 80, 112, 6, 1, True, drop_connect_rate, 3],
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[5, 112, 192, 6, 2, True, drop_connect_rate, 4],
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[3, 192, 320, 6, 1, True, drop_connect_rate, 1],
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]
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def round_repeats(repeats):
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return int(math.ceil(depth_coefficient * repeats))
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if block is None:
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block = InvertedResidual
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if norm_layer is None:
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norm_layer = partial(nn.BatchNorm2d, eps=1e-3, momentum=0.1)
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adjust_channels = partial(
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InvertedResidualConfig.adjust_channels, width_coefficient=width_coefficient
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)
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bneck_conf = partial(
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InvertedResidualConfig, width_coefficient=width_coefficient
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)
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b = 0
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num_blocks = float(sum(round_repeats(i[-1]) for i in default_cnf))
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inverted_residual_setting = []
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for stage, args in enumerate(default_cnf):
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cnf = copy.copy(args)
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for i in range(round_repeats(cnf.pop(-1))):
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if i > 0:
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cnf[-3] = 1
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cnf[1] = cnf[2]
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cnf[-1] = args[-2] * b / num_blocks
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index = str(stage + 1) + chr(i + 97)
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inverted_residual_setting.append(bneck_conf(*cnf, index))
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b += 1
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layers = OrderedDict()
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layers.update(
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{
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"stem_conv": ConvBNActivation(
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in_planes=3,
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out_planes=adjust_channels(32),
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kernel_size=3,
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stride=2,
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norm_layer=norm_layer,
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)
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}
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)
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for cnf in inverted_residual_setting:
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layers.update({cnf.index: block(cnf, norm_layer)})
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last_conv_input_c = inverted_residual_setting[-1].out_c
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last_conv_output_c = adjust_channels(1280)
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layers.update(
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{
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"top": ConvBNActivation(
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in_planes=last_conv_input_c,
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out_planes=last_conv_output_c,
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kernel_size=1,
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norm_layer=norm_layer,
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)
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}
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)
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self.features = nn.Sequential(layers)
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self.avgpool = nn.AdaptiveAvgPool2d(1)
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classifier = []
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if dropout_rate > 0:
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classifier.append(nn.Dropout(p=dropout_rate, inplace=True))
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classifier.append(nn.Linear(last_conv_output_c, num_classes))
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self.classifier = nn.Sequential(*classifier)
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for m in self.modules():
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if isinstance(m, nn.Conv2d):
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nn.init.kaiming_normal_(m.weight, mode="fan_out")
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if m.bias is not None:
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nn.init.zeros_(m.bias)
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elif isinstance(m, nn.BatchNorm2d):
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nn.init.ones_(m.weight)
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nn.init.zeros_(m.bias)
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elif isinstance(m, nn.Linear):
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nn.init.normal_(m.weight, 0, 0.01)
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nn.init.zeros_(m.bias)
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def _forward_impl(self, x: Tensor) -> Tensor:
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x = self.features(x)
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x = self.avgpool(x)
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x = torch.flatten(x, 1)
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x = self.classifier(x)
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return x
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def forward(self, x: Tensor) -> Tensor:
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return self._forward_impl(x)
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def efficientnet_b0(num_classes=1000):
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return EfficientNet(
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width_coefficient=1.0,
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depth_coefficient=1.0,
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dropout_rate=0.2,
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num_classes=num_classes,
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)
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def efficientnet_b1(num_classes=1000):
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return EfficientNet(
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width_coefficient=1.0,
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depth_coefficient=1.1,
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dropout_rate=0.2,
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num_classes=num_classes,
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)
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def efficientnet_b2(num_classes=1000):
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return EfficientNet(
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width_coefficient=1.1,
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depth_coefficient=1.2,
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dropout_rate=0.3,
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num_classes=num_classes,
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)
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def efficientnet_b3(num_classes=1000):
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return EfficientNet(
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width_coefficient=1.2,
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depth_coefficient=1.4,
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dropout_rate=0.3,
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num_classes=num_classes,
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)
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def efficientnet_b4(num_classes=1000):
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return EfficientNet(
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width_coefficient=1.4,
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depth_coefficient=1.8,
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dropout_rate=0.4,
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num_classes=num_classes,
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)
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def efficientnet_b5(num_classes=1000):
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return EfficientNet(
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width_coefficient=1.6,
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depth_coefficient=2.2,
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dropout_rate=0.4,
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num_classes=num_classes,
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)
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def efficientnet_b6(num_classes=1000):
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return EfficientNet(
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width_coefficient=1.8,
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depth_coefficient=2.6,
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dropout_rate=0.5,
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num_classes=num_classes,
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)
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def efficientnet_b7(num_classes=1000):
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return EfficientNet(
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width_coefficient=2.0,
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depth_coefficient=3.1,
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dropout_rate=0.5,
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num_classes=num_classes,
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)
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