commit
1b0c8e7b01
@ -0,0 +1,276 @@
|
||||
"""
|
||||
An implementation of GhostNet Model as defined in:
|
||||
GhostNet: More Features from Cheap Operations. https://arxiv.org/abs/1911.11907
|
||||
The train script of the model is similar to that of MobileNetV3
|
||||
Original model: https://github.com/huawei-noah/CV-backbones/tree/master/ghostnet_pytorch
|
||||
"""
|
||||
import math
|
||||
from functools import partial
|
||||
|
||||
import torch
|
||||
import torch.nn as nn
|
||||
import torch.nn.functional as F
|
||||
|
||||
|
||||
from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
|
||||
from .layers import SelectAdaptivePool2d, Linear, hard_sigmoid
|
||||
from .efficientnet_blocks import SqueezeExcite, ConvBnAct, make_divisible
|
||||
from .helpers import build_model_with_cfg
|
||||
from .registry import register_model
|
||||
|
||||
|
||||
__all__ = ['GhostNet']
|
||||
|
||||
|
||||
def _cfg(url='', **kwargs):
|
||||
return {
|
||||
'url': url, 'num_classes': 1000, 'input_size': (3, 224, 224), 'pool_size': (1, 1),
|
||||
'crop_pct': 0.875, 'interpolation': 'bilinear',
|
||||
'mean': IMAGENET_DEFAULT_MEAN, 'std': IMAGENET_DEFAULT_STD,
|
||||
'first_conv': 'conv_stem', 'classifier': 'classifier',
|
||||
**kwargs
|
||||
}
|
||||
|
||||
|
||||
default_cfgs = {
|
||||
'ghostnet_050': _cfg(url=''),
|
||||
'ghostnet_100': _cfg(
|
||||
url='https://github.com/huawei-noah/CV-backbones/releases/download/ghostnet_pth/ghostnet_1x.pth'),
|
||||
'ghostnet_130': _cfg(url=''),
|
||||
}
|
||||
|
||||
|
||||
_SE_LAYER = partial(SqueezeExcite, gate_fn=hard_sigmoid, divisor=4)
|
||||
|
||||
|
||||
class GhostModule(nn.Module):
|
||||
def __init__(self, inp, oup, kernel_size=1, ratio=2, dw_size=3, stride=1, relu=True):
|
||||
super(GhostModule, self).__init__()
|
||||
self.oup = oup
|
||||
init_channels = math.ceil(oup / ratio)
|
||||
new_channels = init_channels * (ratio - 1)
|
||||
|
||||
self.primary_conv = nn.Sequential(
|
||||
nn.Conv2d(inp, init_channels, kernel_size, stride, kernel_size//2, bias=False),
|
||||
nn.BatchNorm2d(init_channels),
|
||||
nn.ReLU(inplace=True) if relu else nn.Sequential(),
|
||||
)
|
||||
|
||||
self.cheap_operation = nn.Sequential(
|
||||
nn.Conv2d(init_channels, new_channels, dw_size, 1, dw_size//2, groups=init_channels, bias=False),
|
||||
nn.BatchNorm2d(new_channels),
|
||||
nn.ReLU(inplace=True) if relu else nn.Sequential(),
|
||||
)
|
||||
|
||||
def forward(self, x):
|
||||
x1 = self.primary_conv(x)
|
||||
x2 = self.cheap_operation(x1)
|
||||
out = torch.cat([x1, x2], dim=1)
|
||||
return out[:, :self.oup, :, :]
|
||||
|
||||
|
||||
class GhostBottleneck(nn.Module):
|
||||
""" Ghost bottleneck w/ optional SE"""
|
||||
|
||||
def __init__(self, in_chs, mid_chs, out_chs, dw_kernel_size=3,
|
||||
stride=1, act_layer=nn.ReLU, se_ratio=0.):
|
||||
super(GhostBottleneck, self).__init__()
|
||||
has_se = se_ratio is not None and se_ratio > 0.
|
||||
self.stride = stride
|
||||
|
||||
# Point-wise expansion
|
||||
self.ghost1 = GhostModule(in_chs, mid_chs, relu=True)
|
||||
|
||||
# Depth-wise convolution
|
||||
if self.stride > 1:
|
||||
self.conv_dw = nn.Conv2d(
|
||||
mid_chs, mid_chs, dw_kernel_size, stride=stride,
|
||||
padding=(dw_kernel_size-1)//2, groups=mid_chs, bias=False)
|
||||
self.bn_dw = nn.BatchNorm2d(mid_chs)
|
||||
else:
|
||||
self.conv_dw = None
|
||||
self.bn_dw = None
|
||||
|
||||
# Squeeze-and-excitation
|
||||
self.se = _SE_LAYER(mid_chs, se_ratio=se_ratio) if has_se else None
|
||||
|
||||
# Point-wise linear projection
|
||||
self.ghost2 = GhostModule(mid_chs, out_chs, relu=False)
|
||||
|
||||
# shortcut
|
||||
if in_chs == out_chs and self.stride == 1:
|
||||
self.shortcut = nn.Sequential()
|
||||
else:
|
||||
self.shortcut = nn.Sequential(
|
||||
nn.Conv2d(
|
||||
in_chs, in_chs, dw_kernel_size, stride=stride,
|
||||
padding=(dw_kernel_size-1)//2, groups=in_chs, bias=False),
|
||||
nn.BatchNorm2d(in_chs),
|
||||
nn.Conv2d(in_chs, out_chs, 1, stride=1, padding=0, bias=False),
|
||||
nn.BatchNorm2d(out_chs),
|
||||
)
|
||||
|
||||
|
||||
def forward(self, x):
|
||||
residual = x
|
||||
|
||||
# 1st ghost bottleneck
|
||||
x = self.ghost1(x)
|
||||
|
||||
# Depth-wise convolution
|
||||
if self.conv_dw is not None:
|
||||
x = self.conv_dw(x)
|
||||
x = self.bn_dw(x)
|
||||
|
||||
# Squeeze-and-excitation
|
||||
if self.se is not None:
|
||||
x = self.se(x)
|
||||
|
||||
# 2nd ghost bottleneck
|
||||
x = self.ghost2(x)
|
||||
|
||||
x += self.shortcut(residual)
|
||||
return x
|
||||
|
||||
|
||||
class GhostNet(nn.Module):
|
||||
def __init__(self, cfgs, num_classes=1000, width=1.0, dropout=0.2, in_chans=3, output_stride=32):
|
||||
super(GhostNet, self).__init__()
|
||||
# setting of inverted residual blocks
|
||||
assert output_stride == 32, 'only output_stride==32 is valid, dilation not supported'
|
||||
self.cfgs = cfgs
|
||||
self.num_classes = num_classes
|
||||
self.dropout = dropout
|
||||
self.feature_info = []
|
||||
|
||||
# building first layer
|
||||
stem_chs = make_divisible(16 * width, 4)
|
||||
self.conv_stem = nn.Conv2d(in_chans, stem_chs, 3, 2, 1, bias=False)
|
||||
self.feature_info.append(dict(num_chs=stem_chs, reduction=2, module=f'conv_stem'))
|
||||
self.bn1 = nn.BatchNorm2d(stem_chs)
|
||||
self.act1 = nn.ReLU(inplace=True)
|
||||
prev_chs = stem_chs
|
||||
|
||||
# building inverted residual blocks
|
||||
stages = nn.ModuleList([])
|
||||
block = GhostBottleneck
|
||||
stage_idx = 0
|
||||
net_stride = 2
|
||||
for cfg in self.cfgs:
|
||||
layers = []
|
||||
s = 1
|
||||
for k, exp_size, c, se_ratio, s in cfg:
|
||||
out_chs = make_divisible(c * width, 4)
|
||||
mid_chs = make_divisible(exp_size * width, 4)
|
||||
layers.append(block(prev_chs, mid_chs, out_chs, k, s, se_ratio=se_ratio))
|
||||
prev_chs = out_chs
|
||||
if s > 1:
|
||||
net_stride *= 2
|
||||
self.feature_info.append(dict(
|
||||
num_chs=prev_chs, reduction=net_stride, module=f'blocks.{stage_idx}'))
|
||||
stages.append(nn.Sequential(*layers))
|
||||
stage_idx += 1
|
||||
|
||||
out_chs = make_divisible(exp_size * width, 4)
|
||||
stages.append(nn.Sequential(ConvBnAct(prev_chs, out_chs, 1)))
|
||||
self.pool_dim = prev_chs = out_chs
|
||||
|
||||
self.blocks = nn.Sequential(*stages)
|
||||
|
||||
# building last several layers
|
||||
self.num_features = out_chs = 1280
|
||||
self.global_pool = SelectAdaptivePool2d(pool_type='avg')
|
||||
self.conv_head = nn.Conv2d(prev_chs, out_chs, 1, 1, 0, bias=True)
|
||||
self.act2 = nn.ReLU(inplace=True)
|
||||
self.classifier = Linear(out_chs, num_classes)
|
||||
|
||||
def get_classifier(self):
|
||||
return self.classifier
|
||||
|
||||
def reset_classifier(self, num_classes, global_pool='avg'):
|
||||
self.num_classes = num_classes
|
||||
# cannot meaningfully change pooling of efficient head after creation
|
||||
self.global_pool = SelectAdaptivePool2d(pool_type=global_pool)
|
||||
self.classifier = Linear(self.pool_dim, num_classes) if num_classes > 0 else nn.Identity()
|
||||
|
||||
def forward_features(self, x):
|
||||
x = self.conv_stem(x)
|
||||
x = self.bn1(x)
|
||||
x = self.act1(x)
|
||||
x = self.blocks(x)
|
||||
x = self.global_pool(x)
|
||||
x = self.conv_head(x)
|
||||
x = self.act2(x)
|
||||
return x
|
||||
|
||||
def forward(self, x):
|
||||
x = self.forward_features(x)
|
||||
if not self.global_pool.is_identity():
|
||||
x = x.view(x.size(0), -1)
|
||||
if self.dropout > 0.:
|
||||
x = F.dropout(x, p=self.dropout, training=self.training)
|
||||
x = self.classifier(x)
|
||||
return x
|
||||
|
||||
|
||||
def _create_ghostnet(variant, width=1.0, pretrained=False, **kwargs):
|
||||
"""
|
||||
Constructs a GhostNet model
|
||||
"""
|
||||
cfgs = [
|
||||
# k, t, c, SE, s
|
||||
# stage1
|
||||
[[3, 16, 16, 0, 1]],
|
||||
# stage2
|
||||
[[3, 48, 24, 0, 2]],
|
||||
[[3, 72, 24, 0, 1]],
|
||||
# stage3
|
||||
[[5, 72, 40, 0.25, 2]],
|
||||
[[5, 120, 40, 0.25, 1]],
|
||||
# stage4
|
||||
[[3, 240, 80, 0, 2]],
|
||||
[[3, 200, 80, 0, 1],
|
||||
[3, 184, 80, 0, 1],
|
||||
[3, 184, 80, 0, 1],
|
||||
[3, 480, 112, 0.25, 1],
|
||||
[3, 672, 112, 0.25, 1]
|
||||
],
|
||||
# stage5
|
||||
[[5, 672, 160, 0.25, 2]],
|
||||
[[5, 960, 160, 0, 1],
|
||||
[5, 960, 160, 0.25, 1],
|
||||
[5, 960, 160, 0, 1],
|
||||
[5, 960, 160, 0.25, 1]
|
||||
]
|
||||
]
|
||||
model_kwargs = dict(
|
||||
cfgs=cfgs,
|
||||
width=width,
|
||||
**kwargs,
|
||||
)
|
||||
return build_model_with_cfg(
|
||||
GhostNet, variant, pretrained,
|
||||
default_cfg=default_cfgs[variant],
|
||||
feature_cfg=dict(flatten_sequential=True),
|
||||
**model_kwargs)
|
||||
|
||||
|
||||
@register_model
|
||||
def ghostnet_050(pretrained=False, **kwargs):
|
||||
""" GhostNet-0.5x """
|
||||
model = _create_ghostnet('ghostnet_050', width=0.5, pretrained=pretrained, **kwargs)
|
||||
return model
|
||||
|
||||
|
||||
@register_model
|
||||
def ghostnet_100(pretrained=False, **kwargs):
|
||||
""" GhostNet-1.0x """
|
||||
model = _create_ghostnet('ghostnet_100', width=1.0, pretrained=pretrained, **kwargs)
|
||||
return model
|
||||
|
||||
|
||||
@register_model
|
||||
def ghostnet_130(pretrained=False, **kwargs):
|
||||
""" GhostNet-1.3x """
|
||||
model = _create_ghostnet('ghostnet_130', width=1.3, pretrained=pretrained, **kwargs)
|
||||
return model
|
Loading…
Reference in new issue