2021-12-30 10:24:47 +08:00

216 lines
6.5 KiB
Python

#!/usr/bin/env python3
# Copyright 2021 Xiaomi Corp. (authors: Fangjun Kuang
# Mingshuang Luo)
#
# See ../../../../LICENSE for clarification regarding multiple authors
#
# 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.
import math
import torch.nn as nn
def conv3x3(in_planes, out_planes, stride=1):
return nn.Conv2d(
in_planes,
out_planes,
kernel_size=3,
stride=stride,
padding=1,
bias=False,
)
class BasicBlock(nn.Module):
expansion = 1
def __init__(self, inplanes, planes, stride=1, downsample=None):
super(BasicBlock, self).__init__()
self.conv1 = conv3x3(inplanes, planes, stride)
self.bn1 = nn.BatchNorm2d(planes)
self.relu = nn.ReLU(inplace=True)
self.conv2 = conv3x3(planes, planes)
self.bn2 = nn.BatchNorm2d(planes)
self.downsample = downsample
self.stride = stride
def forward(self, x):
residual = x
out = self.conv1(x)
out = self.bn1(out)
out = self.relu(out)
out = self.conv2(out)
out = self.bn2(out)
if self.downsample is not None:
residual = self.downsample(x)
out += residual
out = self.relu(out)
return out
class ResNet(nn.Module):
def __init__(self, block, layers):
self.inplanes = 64
super(ResNet, self).__init__()
self.layer1 = self._make_layer(block, 64, layers[0])
self.layer2 = self._make_layer(block, 128, layers[1], stride=2)
self.layer3 = self._make_layer(block, 256, layers[2], stride=2)
self.layer4 = self._make_layer(block, 512, layers[3], stride=2)
self.avgpool = nn.AdaptiveAvgPool2d(1)
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(2.0 / n))
elif isinstance(m, nn.BatchNorm2d):
m.weight.data.fill_(1)
m.bias.data.zero_()
elif isinstance(m, nn.BatchNorm1d):
m.weight.data.fill_(1)
m.bias.data.zero_()
def _make_layer(self, block, planes, blocks, stride=1):
downsample = None
if stride != 1 or self.inplanes != planes * block.expansion:
downsample = nn.Sequential(
nn.Conv2d(
self.inplanes,
planes * block.expansion,
kernel_size=1,
stride=stride,
bias=False,
),
nn.BatchNorm2d(planes * block.expansion),
)
layers = []
layers.append(block(self.inplanes, planes, stride, downsample))
self.inplanes = planes * block.expansion
for i in range(1, blocks):
layers.append(block(self.inplanes, planes))
return nn.Sequential(*layers)
def forward(self, x):
x = self.layer1(x)
x = self.layer2(x)
x = self.layer3(x)
x = self.layer4(x)
x = self.avgpool(x)
x = x.view(x.size(0), -1)
return x
class VisualNet2(nn.Module):
def __init__(self, num_classes):
"""
Args:
num_classes:
The output dimension of the visualnet2 model.
"""
super().__init__()
self.num_classes = num_classes
self.inputDim = 512
self.conv3d = nn.Conv3d(
3,
64,
kernel_size=(5, 7, 7),
stride=(1, 2, 2),
padding=(2, 3, 3),
bias=False,
)
self.bn = nn.BatchNorm3d(64, track_running_stats=True)
self.relu = nn.ReLU(True)
self.maxpool = nn.MaxPool3d(
kernel_size=(1, 3, 3), stride=(1, 2, 2), padding=(0, 1, 1)
)
# resnet
self.resnet18 = ResNet(BasicBlock, [2, 2, 2, 2])
# grus
self.gru1 = nn.GRU(512, 512, 1, bidirectional=True)
self.gru2 = nn.GRU(1024, 512, 1, bidirectional=True)
# dropout
self.dropout = nn.Dropout(p=0.5)
# fc
self.linear = nn.Linear(1024, self.num_classes)
# initialize
self._initialize_weights()
def forward(self, x):
frameLen = x.size(2)
x = self.conv3d(x)
x = self.bn(x)
x = self.relu(x)
x = self.maxpool(x)
x = x.transpose(1, 2)
x = x.contiguous()
x = x.view(-1, 64, x.size(3), x.size(4))
x = self.resnet18(x)
x = self.dropout(x)
x = x.view(-1, frameLen, self.inputDim)
x = x.permute(1, 0, 2)
x, h = self.gru1(x)
x, h = self.gru2(self.dropout(x))
x = self.linear(x)
x = x.permute(1, 0, 2)
x = nn.functional.log_softmax(x, dim=-1)
return x
def _initialize_weights(self):
for m in self.modules():
if isinstance(m, nn.Conv3d):
n = (
m.kernel_size[0]
* m.kernel_size[1]
* m.kernel_size[2]
* m.out_channels
)
m.weight.data.normal_(0, math.sqrt(2.0 / n))
if m.bias is not None:
m.bias.data.zero_()
elif isinstance(m, nn.Conv2d):
n = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
m.weight.data.normal_(0, math.sqrt(2.0 / n))
if m.bias is not None:
m.bias.data.zero_()
elif isinstance(m, nn.Conv1d):
n = m.kernel_size[0] * m.out_channels
m.weight.data.normal_(0, math.sqrt(2.0 / n))
if m.bias is not None:
m.bias.data.zero_()
elif isinstance(m, nn.BatchNorm3d):
m.weight.data.fill_(1)
m.bias.data.zero_()
elif isinstance(m, nn.BatchNorm2d):
m.weight.data.fill_(1)
m.bias.data.zero_()
elif isinstance(m, nn.BatchNorm1d):
m.weight.data.fill_(1)
m.bias.data.zero_()