PulseFocusPlatform/static/ppdet/modeling/backbones/res2net.py

221 lines
7.6 KiB
Python

# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from paddle import fluid
from ppdet.core.workspace import register, serializable
from .nonlocal_helper import add_space_nonlocal
from .resnet import ResNet
__all__ = ['Res2Net', 'Res2NetC5']
@register
@serializable
class Res2Net(ResNet):
"""
Res2Net, see https://arxiv.org/abs/1904.01169
Args:
depth (int): Res2Net depth, should be 50, 101, 152, 200.
width (int): Res2Net width
scales (int): Res2Net scale
freeze_at (int): freeze the backbone at which stage
norm_type (str): normalization type, 'bn'/'sync_bn'/'affine_channel'
freeze_norm (bool): freeze normalization layers
norm_decay (float): weight decay for normalization layer weights
variant (str): Res2Net variant, supports 'a', 'b', 'c', 'd' currently
feature_maps (list): index of stages whose feature maps are returned
dcn_v2_stages (list): index of stages who select deformable conv v2
nonlocal_stages (list): index of stages who select nonlocal networks
"""
__shared__ = ['norm_type', 'freeze_norm', 'weight_prefix_name']
def __init__(
self,
depth=50,
width=26,
scales=4,
freeze_at=2,
norm_type='bn',
freeze_norm=True,
norm_decay=0.,
variant='b',
feature_maps=[2, 3, 4, 5],
dcn_v2_stages=[],
weight_prefix_name='',
nonlocal_stages=[], ):
super(Res2Net, self).__init__(
depth=depth,
freeze_at=freeze_at,
norm_type=norm_type,
freeze_norm=freeze_norm,
norm_decay=norm_decay,
variant=variant,
feature_maps=feature_maps,
dcn_v2_stages=dcn_v2_stages,
weight_prefix_name=weight_prefix_name,
nonlocal_stages=nonlocal_stages)
assert depth >= 50, "just support depth>=50 in res2net, but got depth=".format(
depth)
# res2net config
self.scales = scales
self.width = width
basic_width = self.width * self.scales
self.num_filters1 = [basic_width * t for t in [1, 2, 4, 8]]
self.num_filters2 = [256 * t for t in [1, 2, 4, 8]]
self.num_filters = [64, 128, 384, 768]
def bottleneck(self,
input,
num_filters1,
num_filters2,
stride,
is_first,
name,
dcn_v2=False):
conv0 = self._conv_norm(
input=input,
num_filters=num_filters1,
filter_size=1,
stride=1,
act='relu',
name=name + '_branch2a')
xs = fluid.layers.split(conv0, self.scales, 1)
ys = []
for s in range(self.scales - 1):
if s == 0 or stride == 2:
ys.append(
self._conv_norm(
input=xs[s],
num_filters=num_filters1 // self.scales,
stride=stride,
filter_size=3,
act='relu',
name=name + '_branch2b_' + str(s + 1),
dcn_v2=dcn_v2))
else:
ys.append(
self._conv_norm(
input=xs[s] + ys[-1],
num_filters=num_filters1 // self.scales,
stride=stride,
filter_size=3,
act='relu',
name=name + '_branch2b_' + str(s + 1),
dcn_v2=dcn_v2))
if stride == 1:
ys.append(xs[-1])
else:
ys.append(
fluid.layers.pool2d(
input=xs[-1],
pool_size=3,
pool_stride=stride,
pool_padding=1,
pool_type='avg'))
conv1 = fluid.layers.concat(ys, axis=1)
conv2 = self._conv_norm(
input=conv1,
num_filters=num_filters2,
filter_size=1,
act=None,
name=name + "_branch2c")
short = self._shortcut(
input, num_filters2, stride, is_first, name=name + "_branch1")
return fluid.layers.elementwise_add(
x=short, y=conv2, act='relu', name=name + ".add.output.5")
def layer_warp(self, input, stage_num):
"""
Args:
input (Variable): input variable.
stage_num (int): the stage number, should be 2, 3, 4, 5
Returns:
The last variable in endpoint-th stage.
"""
assert stage_num in [2, 3, 4, 5]
stages, block_func = self.depth_cfg[self.depth]
count = stages[stage_num - 2]
ch_out = self.stage_filters[stage_num - 2]
is_first = False if stage_num != 2 else True
dcn_v2 = True if stage_num in self.dcn_v2_stages else False
num_filters1 = self.num_filters1[stage_num - 2]
num_filters2 = self.num_filters2[stage_num - 2]
nonlocal_mod = 1000
if stage_num in self.nonlocal_stages:
nonlocal_mod = self.nonlocal_mod_cfg[
self.depth] if stage_num == 4 else 2
# Make the layer name and parameter name consistent
# with ImageNet pre-trained model
conv = input
for i in range(count):
conv_name = self.na.fix_layer_warp_name(stage_num, count, i)
if self.depth < 50:
is_first = True if i == 0 and stage_num == 2 else False
conv = block_func(
input=conv,
num_filters1=num_filters1,
num_filters2=num_filters2,
stride=2 if i == 0 and stage_num != 2 else 1,
is_first=is_first,
name=conv_name,
dcn_v2=dcn_v2)
# add non local model
dim_in = conv.shape[1]
nonlocal_name = "nonlocal_conv{}".format(stage_num)
if i % nonlocal_mod == nonlocal_mod - 1:
conv = add_space_nonlocal(conv, dim_in, dim_in,
nonlocal_name + '_{}'.format(i),
int(dim_in / 2))
return conv
@register
@serializable
class Res2NetC5(Res2Net):
__doc__ = Res2Net.__doc__
def __init__(self,
depth=50,
width=26,
scales=4,
freeze_at=2,
norm_type='bn',
freeze_norm=True,
norm_decay=0.,
variant='b',
feature_maps=[5],
weight_prefix_name=''):
super(Res2NetC5, self).__init__(depth, width, scales, freeze_at,
norm_type, freeze_norm, norm_decay,
variant, feature_maps)
self.severed_head = True