import torch.nn as nn
from mmcv.cnn import constant_init, kaiming_init
from mmcv.runner import load_checkpoint
from mmdet.core import auto_fp16
from mmdet.models.backbones import ResNet
from mmdet.models.builder import SHARED_HEADS
from mmdet.models.utils import ResLayer as _ResLayer
from mmdet.utils import get_root_logger
@SHARED_HEADS.register_module()
class ResLayer(nn.Module):
def __init__(self,
depth,
stage=3,
stride=2,
dilation=1,
style='pytorch',
norm_cfg=dict(type='BN', requires_grad=True),
norm_eval=True,
with_cp=False,
dcn=None):
super(ResLayer, self).__init__()
self.norm_eval = norm_eval
self.norm_cfg = norm_cfg
self.stage = stage
self.fp16_enabled = False
block, stage_blocks = ResNet.arch_settings[depth]
stage_block = stage_blocks[stage]
planes = 64 * 2**stage
inplanes = 64 * 2**(stage - 1) * block.expansion
res_layer = _ResLayer(
block,
inplanes,
planes,
stage_block,
stride=stride,
dilation=dilation,
style=style,
with_cp=with_cp,
norm_cfg=self.norm_cfg,
dcn=dcn)
self.add_module(f'layer{stage + 1}', res_layer)
def init_weights(self, pretrained=None):
"""Initialize the weights in the module.
Args:
pretrained (str, optional): Path to pre-trained weights.
Defaults to None.
"""
if isinstance(pretrained, str):
logger = get_root_logger()
load_checkpoint(self, pretrained, strict=False, logger=logger)
elif pretrained is None:
for m in self.modules():
if isinstance(m, nn.Conv2d):
kaiming_init(m)
elif isinstance(m, nn.BatchNorm2d):
constant_init(m, 1)
else:
raise TypeError('pretrained must be a str or None')
@auto_fp16()
def forward(self, x):
res_layer = getattr(self, f'layer{self.stage + 1}')
out = res_layer(x)
return out
def train(self, mode=True):
super(ResLayer, self).train(mode)
if self.norm_eval:
for m in self.modules():
if isinstance(m, nn.BatchNorm2d):
m.eval()
