fast-reid/fastreid/modeling/backbones/resnest.py

366 lines
15 KiB
Python

# encoding: utf-8
# based on:
# https://github.com/zhanghang1989/ResNeSt/blob/master/resnest/torch/resnest.py
"""ResNeSt models"""
import logging
import math
import torch
from torch import nn
from fastreid.layers import SplAtConv2d, get_norm, DropBlock2D
from fastreid.utils.checkpoint import get_unexpected_parameters_message, get_missing_parameters_message
from .build import BACKBONE_REGISTRY
logger = logging.getLogger(__name__)
_url_format = 'https://s3.us-west-1.wasabisys.com/resnest/torch/{}-{}.pth'
_model_sha256 = {name: checksum for checksum, name in [
('528c19ca', 'resnest50'),
('22405ba7', 'resnest101'),
('75117900', 'resnest200'),
('0cc87c48', 'resnest269'),
]}
def short_hash(name):
if name not in _model_sha256:
raise ValueError('Pretrained model for {name} is not available.'.format(name=name))
return _model_sha256[name][:8]
model_urls = {name: _url_format.format(name, short_hash(name)) for
name in _model_sha256.keys()
}
class Bottleneck(nn.Module):
"""ResNet Bottleneck
"""
# pylint: disable=unused-argument
expansion = 4
def __init__(self, inplanes, planes, stride=1, downsample=None,
radix=1, cardinality=1, bottleneck_width=64,
avd=False, avd_first=False, dilation=1, is_first=False,
rectified_conv=False, rectify_avg=False,
norm_layer=None, dropblock_prob=0.0, last_gamma=False):
super(Bottleneck, self).__init__()
group_width = int(planes * (bottleneck_width / 64.)) * cardinality
self.conv1 = nn.Conv2d(inplanes, group_width, kernel_size=1, bias=False)
self.bn1 = get_norm(norm_layer, group_width)
self.dropblock_prob = dropblock_prob
self.radix = radix
self.avd = avd and (stride > 1 or is_first)
self.avd_first = avd_first
if self.avd:
self.avd_layer = nn.AvgPool2d(3, stride, padding=1)
stride = 1
if dropblock_prob > 0.0:
self.dropblock1 = DropBlock2D(dropblock_prob, 3)
if radix == 1:
self.dropblock2 = DropBlock2D(dropblock_prob, 3)
self.dropblock3 = DropBlock2D(dropblock_prob, 3)
if radix >= 1:
self.conv2 = SplAtConv2d(
group_width, group_width, kernel_size=3,
stride=stride, padding=dilation,
dilation=dilation, groups=cardinality, bias=False,
radix=radix, rectify=rectified_conv,
rectify_avg=rectify_avg,
norm_layer=norm_layer,
dropblock_prob=dropblock_prob)
elif rectified_conv:
from rfconv import RFConv2d
self.conv2 = RFConv2d(
group_width, group_width, kernel_size=3, stride=stride,
padding=dilation, dilation=dilation,
groups=cardinality, bias=False,
average_mode=rectify_avg)
self.bn2 = get_norm(norm_layer, group_width)
else:
self.conv2 = nn.Conv2d(
group_width, group_width, kernel_size=3, stride=stride,
padding=dilation, dilation=dilation,
groups=cardinality, bias=False)
self.bn2 = get_norm(norm_layer, group_width)
self.conv3 = nn.Conv2d(
group_width, planes * 4, kernel_size=1, bias=False)
self.bn3 = get_norm(norm_layer, planes * 4)
if last_gamma:
from torch.nn.init import zeros_
zeros_(self.bn3.weight)
self.relu = nn.ReLU(inplace=True)
self.downsample = downsample
self.dilation = dilation
self.stride = stride
def forward(self, x):
residual = x
out = self.conv1(x)
out = self.bn1(out)
if self.dropblock_prob > 0.0:
out = self.dropblock1(out)
out = self.relu(out)
if self.avd and self.avd_first:
out = self.avd_layer(out)
out = self.conv2(out)
if self.radix == 0:
out = self.bn2(out)
if self.dropblock_prob > 0.0:
out = self.dropblock2(out)
out = self.relu(out)
if self.avd and not self.avd_first:
out = self.avd_layer(out)
out = self.conv3(out)
out = self.bn3(out)
if self.dropblock_prob > 0.0:
out = self.dropblock3(out)
if self.downsample is not None:
residual = self.downsample(x)
out += residual
out = self.relu(out)
return out
class ResNeSt(nn.Module):
"""ResNet Variants
Parameters
----------
block : Block
Class for the residual block. Options are BasicBlockV1, BottleneckV1.
layers : list of int
Numbers of layers in each block
classes : int, default 1000
Number of classification classes.
dilated : bool, default False
Applying dilation strategy to pretrained ResNet yielding a stride-8 model,
typically used in Semantic Segmentation.
norm_layer : object
Normalization layer used in backbone network (default: :class:`mxnet.gluon.nn.BatchNorm`;
for Synchronized Cross-GPU BachNormalization).
Reference:
- He, Kaiming, et al. "Deep residual learning for image recognition." Proceedings of the IEEE conference on computer vision and pattern recognition. 2016.
- Yu, Fisher, and Vladlen Koltun. "Multi-scale context aggregation by dilated convolutions."
"""
# pylint: disable=unused-variable
def __init__(self, last_stride, block, layers, radix=1, groups=1, bottleneck_width=64,
dilated=False, dilation=1,
deep_stem=False, stem_width=64, avg_down=False,
rectified_conv=False, rectify_avg=False,
avd=False, avd_first=False,
final_drop=0.0, dropblock_prob=0,
last_gamma=False, norm_layer="BN"):
if last_stride == 1: dilation = 2
self.cardinality = groups
self.bottleneck_width = bottleneck_width
# ResNet-D params
self.inplanes = stem_width * 2 if deep_stem else 64
self.avg_down = avg_down
self.last_gamma = last_gamma
# ResNeSt params
self.radix = radix
self.avd = avd
self.avd_first = avd_first
super().__init__()
self.rectified_conv = rectified_conv
self.rectify_avg = rectify_avg
if rectified_conv:
from rfconv import RFConv2d
conv_layer = RFConv2d
else:
conv_layer = nn.Conv2d
conv_kwargs = {'average_mode': rectify_avg} if rectified_conv else {}
if deep_stem:
self.conv1 = nn.Sequential(
conv_layer(3, stem_width, kernel_size=3, stride=2, padding=1, bias=False, **conv_kwargs),
get_norm(norm_layer, stem_width),
nn.ReLU(inplace=True),
conv_layer(stem_width, stem_width, kernel_size=3, stride=1, padding=1, bias=False, **conv_kwargs),
get_norm(norm_layer, stem_width),
nn.ReLU(inplace=True),
conv_layer(stem_width, stem_width * 2, kernel_size=3, stride=1, padding=1, bias=False, **conv_kwargs),
)
else:
self.conv1 = conv_layer(3, 64, kernel_size=7, stride=2, padding=3,
bias=False, **conv_kwargs)
self.bn1 = get_norm(norm_layer, self.inplanes)
self.relu = nn.ReLU(inplace=True)
self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1)
self.layer1 = self._make_layer(block, 64, layers[0], norm_layer=norm_layer, is_first=False)
self.layer2 = self._make_layer(block, 128, layers[1], stride=2, norm_layer=norm_layer)
if dilated or dilation == 4:
self.layer3 = self._make_layer(block, 256, layers[2], stride=1,
dilation=2, norm_layer=norm_layer,
dropblock_prob=dropblock_prob)
self.layer4 = self._make_layer(block, 512, layers[3], stride=1,
dilation=4, norm_layer=norm_layer,
dropblock_prob=dropblock_prob)
elif dilation == 2:
self.layer3 = self._make_layer(block, 256, layers[2], stride=2,
dilation=1, norm_layer=norm_layer,
dropblock_prob=dropblock_prob)
self.layer4 = self._make_layer(block, 512, layers[3], stride=1,
dilation=2, norm_layer=norm_layer,
dropblock_prob=dropblock_prob)
else:
self.layer3 = self._make_layer(block, 256, layers[2], stride=2,
norm_layer=norm_layer,
dropblock_prob=dropblock_prob)
self.layer4 = self._make_layer(block, 512, layers[3], stride=2,
norm_layer=norm_layer,
dropblock_prob=dropblock_prob)
self.drop = nn.Dropout(final_drop) if final_drop > 0.0 else None
for m in self.modules():
if isinstance(m, nn.Conv2d):
n = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
m.weight.data.normal_(0, math.sqrt(2. / n))
def _make_layer(self, block, planes, blocks, stride=1, dilation=1, norm_layer=None,
dropblock_prob=0.0, is_first=True):
downsample = None
if stride != 1 or self.inplanes != planes * block.expansion:
down_layers = []
if self.avg_down:
if dilation == 1:
down_layers.append(nn.AvgPool2d(kernel_size=stride, stride=stride,
ceil_mode=True, count_include_pad=False))
else:
down_layers.append(nn.AvgPool2d(kernel_size=1, stride=1,
ceil_mode=True, count_include_pad=False))
down_layers.append(nn.Conv2d(self.inplanes, planes * block.expansion,
kernel_size=1, stride=1, bias=False))
else:
down_layers.append(nn.Conv2d(self.inplanes, planes * block.expansion,
kernel_size=1, stride=stride, bias=False))
down_layers.append(get_norm(norm_layer, planes * block.expansion))
downsample = nn.Sequential(*down_layers)
layers = []
if dilation == 1 or dilation == 2:
layers.append(block(self.inplanes, planes, stride, downsample=downsample,
radix=self.radix, cardinality=self.cardinality,
bottleneck_width=self.bottleneck_width,
avd=self.avd, avd_first=self.avd_first,
dilation=1, is_first=is_first, rectified_conv=self.rectified_conv,
rectify_avg=self.rectify_avg,
norm_layer=norm_layer, dropblock_prob=dropblock_prob,
last_gamma=self.last_gamma))
elif dilation == 4:
layers.append(block(self.inplanes, planes, stride, downsample=downsample,
radix=self.radix, cardinality=self.cardinality,
bottleneck_width=self.bottleneck_width,
avd=self.avd, avd_first=self.avd_first,
dilation=2, is_first=is_first, rectified_conv=self.rectified_conv,
rectify_avg=self.rectify_avg,
norm_layer=norm_layer, dropblock_prob=dropblock_prob,
last_gamma=self.last_gamma))
else:
raise RuntimeError("=> unknown dilation size: {}".format(dilation))
self.inplanes = planes * block.expansion
for i in range(1, blocks):
layers.append(block(self.inplanes, planes,
radix=self.radix, cardinality=self.cardinality,
bottleneck_width=self.bottleneck_width,
avd=self.avd, avd_first=self.avd_first,
dilation=dilation, rectified_conv=self.rectified_conv,
rectify_avg=self.rectify_avg,
norm_layer=norm_layer, dropblock_prob=dropblock_prob,
last_gamma=self.last_gamma))
return nn.Sequential(*layers)
def forward(self, x):
x = self.conv1(x)
x = self.bn1(x)
x = self.relu(x)
x = self.maxpool(x)
x = self.layer1(x)
x = self.layer2(x)
x = self.layer3(x)
x = self.layer4(x)
return x
@BACKBONE_REGISTRY.register()
def build_resnest_backbone(cfg):
"""
Create a ResNest instance from config.
Returns:
ResNet: a :class:`ResNet` instance.
"""
# fmt: off
pretrain = cfg.MODEL.BACKBONE.PRETRAIN
pretrain_path = cfg.MODEL.BACKBONE.PRETRAIN_PATH
last_stride = cfg.MODEL.BACKBONE.LAST_STRIDE
bn_norm = cfg.MODEL.BACKBONE.NORM
depth = cfg.MODEL.BACKBONE.DEPTH
# fmt: on
num_blocks_per_stage = {
"50x": [3, 4, 6, 3],
"101x": [3, 4, 23, 3],
"200x": [3, 24, 36, 3],
"269x": [3, 30, 48, 8],
}[depth]
stem_width = {
"50x": 32,
"101x": 64,
"200x": 64,
"269x": 64,
}[depth]
model = ResNeSt(last_stride, Bottleneck, num_blocks_per_stage,
radix=2, groups=1, bottleneck_width=64,
deep_stem=True, stem_width=stem_width, avg_down=True,
avd=True, avd_first=False, norm_layer=bn_norm)
if pretrain:
# Load pretrain path if specifically
if pretrain_path:
try:
state_dict = torch.load(pretrain_path, map_location=torch.device('cpu'))
logger.info(f"Loading pretrained model from {pretrain_path}")
except FileNotFoundError as e:
logger.info(f'{pretrain_path} is not found! Please check this path.')
raise e
except KeyError as e:
logger.info("State dict keys error! Please check the state dict.")
raise e
else:
state_dict = torch.hub.load_state_dict_from_url(
model_urls['resnest' + depth[:-1]], progress=True, check_hash=True, map_location=torch.device('cpu'))
incompatible = model.load_state_dict(state_dict, strict=False)
if incompatible.missing_keys:
logger.info(
get_missing_parameters_message(incompatible.missing_keys)
)
if incompatible.unexpected_keys:
logger.info(
get_unexpected_parameters_message(incompatible.unexpected_keys)
)
return model