%2C%20Positive%20Samples%20(Green%2C%20Left%20Bottom)%2C%20Negative%20Samples%20(Red%2C%20Right%20Bottom).png){kind=link}
%20-%20Architecture.png){kind=link}
%2C%20Efficient%20Grid%20Size%20Reduction%20(Bottom%20Left)%2C%20Detailed%20Architecture%20of%20Efficient%20Grid%20Size%20Reduction%20(Right).png){kind=link}
%2C%20Efficient%20Grid%20Size%20Reduction%20(Bottom%20Left)%2C%20Detailed%20Architecture%20of%20Efficient%20Grid%20Size%20Reduction%20(Right).png){kind=link}
.png){kind=link}
%20and%20FSRCNN%20(Bottom).png){kind=link}
Papers about algorithms related to the field of AI, Machine Learning, Deep Learning and Neural Networks. In this repository there dozens of technical articles describing algorithms related to Artificial Intelligence, and also with Code
In deep learning, a convolutional neural network (CNN, or ConvNet) is a class of deep neural networks, most commonly applied to analyzing visual imagery. They are also known as shift invariant or space invariant artificial neural networks (SIANN), based on their shared-weights architecture and translation invariance characteristics. They have applications in image and video recognition, recommender systems, image classification, medical image analysis, natural language processing, brain-computer interfaces,[6] and financial time series.
CNNs are regularized versions of multilayer perceptrons. Multilayer perceptrons usually mean fully connected networks, that is, each neuron in one layer is connected to all neurons in the next layer. The "fully-connectedness" of these networks makes them prone to overfitting data. Typical ways of regularization include adding some form of magnitude measurement of weights to the loss function. CNNs take a different approach towards regularization: they take advantage of the hierarchical pattern in data and assemble more complex patterns using smaller and simpler patterns. Therefore, on the scale of connectedness and complexity, CNNs are on the lower extreme.
Convolutional networks were inspired by biological processes in that the connectivity pattern between neurons resembles the organization of the animal visual cortex. Individual cortical neurons respond to stimuli only in a restricted region of the visual field known as the receptive field. The receptive fields of different neurons partially overlap such that they cover the entire visual field.
There are various architectures of CNNs available which have been key in building algorithms which power and shall power AI as a whole in the foreseeable future. Some of them have been listed below:
(https://paperswithcode.com/methods/category/convolutional-neural-networks)
Convolutional Neural Networks are used to extract features from images, employing convolutions as their primary operator. Below you can find a continuously updating list of convolutional neural networks.
The methods are listed (by the gretest for the lowest order) of the number of articles found describing them:
- ResNet
- AlexNet
- VGG
- DenseNet
- MobileNetV2
- GoogLeNet
- ResNeXt
- Darknet-53
- EfficientNet
- Xception
- SqueezeNet
- Inception-v3
- LeNet
- MobileNetV1
- Darknet-19
- WideResNet
- ShuffleNet
- MobileNetV3
- SENet
- CSPDarknet53
- MnasNet
- HRNet
- Inception-ResNet-v2
- PCB
- DPN
- ShuffleNet v2
- Inception v2
- Inception-v4
- OverFeat
- CheXNet
- PyramidNet
- AmoebaNet
- FractalNet
- RevNet
- SimpleNet
- FBNet
- DetNet
- SpineNet
- SNet
- ResNet-D
- ZFNet
- Single-path NAS
- SqueezeNeXt
- MixNet
- PeleeNet
- CSPResNeXt
- GhostNet
- ResNeSt
- DenseNet-Elastic
- RegNetY
- ScaleNet
- VoVNet
- ProxylessNet-GPU
- ProxylessNet-Mobile
- Assemble-ResNet
- McKernel
- ProxylessNet-CPU
- Big-Little Net
- TResNet
- DenseNAS-B
- DetNASNet
- GreedyNAS-C
- RandWire
- CSPDenseNet-Elastic
- PReLU-Net
- DiCENet
- Deep-CAPTCHA
- CSPDenseNet
- CornerNet-Squeeze Hourglass
- RegNetX
- SPP-Net
- DenseNAS-A
- ResNeXt-Elastic
- VoVNetV2
- MultiGrain
- DenseNAS-C
- ESPNetv2
- MoGA-C
- Harm-Net
- CSPPeleeNet
- uNetXST
- GreedyNAS-B
- MoGA-B
- ECA-Net
- SCARLET
- MoGA-A
- GreedyNAS-A
- SKNet
Introduced by He et al. in Deep Residual Learning for Image Recognition
Residual Networks, or ResNets, learn residual functions with reference to the layer inputs, instead of learning unreferenced functions. Instead of hoping each few stacked layers directly fit a desired underlying mapping, residual nets let these layers fit a residual mapping. They stack residual blocks on top of each other to form network: e.g. a ResNet-50 has fifty layers using these blocks.
Formally, denoting the desired underlying mapping as H(x), we let the stacked nonlinear layers fit another mapping of f(x) := H(s) - x . The original mapping is recast into f(x) + x.
There is empirical evidence that these types of network are easier to optimize, and can gain accuracy from considerably increased depth.
After the celebrated victory of AlexNet [1] at the LSVRC2012 classification contest, deep Residual Network [2] was arguably the most groundbreaking work in the computer vision/deep learning community in the last few years. ResNet makes it possible to train up to hundreds or even thousands of layers and still achieves compelling performance.
Taking advantage of its powerful representational ability, the performance of many computer vision applications other than image classification have been boosted, such as object detection and face recognition.
Since ResNet blew people’s mind in 2015, many in the research community have dived into the secrets of its success, many refinements have been made in the architecture. This article is divided into two parts, in the first part I am going to give a little bit of background knowledge for those who are unfamiliar with ResNet, in the second I will review some of the papers I read recently regarding different variants and interpretations of the ResNet architecture.
source - Deep Residual Learning for Image Recognition
import torch
import torch.nn as nn
from .utils import load_state_dict_from_url
__all__ = ['ResNet', 'resnet18', 'resnet34', 'resnet50', 'resnet101',
'resnet152', 'resnext50_32x4d', 'resnext101_32x8d',
'wide_resnet50_2', 'wide_resnet101_2']
model_urls = {
'resnet18': 'https://download.pytorch.org/models/resnet18-5c106cde.pth',
'resnet34': 'https://download.pytorch.org/models/resnet34-333f7ec4.pth',
'resnet50': 'https://download.pytorch.org/models/resnet50-19c8e357.pth',
'resnet101': 'https://download.pytorch.org/models/resnet101-5d3b4d8f.pth',
'resnet152': 'https://download.pytorch.org/models/resnet152-b121ed2d.pth',
'resnext50_32x4d': 'https://download.pytorch.org/models/resnext50_32x4d-7cdf4587.pth',
'resnext101_32x8d': 'https://download.pytorch.org/models/resnext101_32x8d-8ba56ff5.pth',
'wide_resnet50_2': 'https://download.pytorch.org/models/wide_resnet50_2-95faca4d.pth',
'wide_resnet101_2': 'https://download.pytorch.org/models/wide_resnet101_2-32ee1156.pth',
}
def conv3x3(in_planes, out_planes, stride=1, groups=1, dilation=1):
"""3x3 convolution with padding"""
return nn.Conv2d(in_planes, out_planes, kernel_size=3, stride=stride,
padding=dilation, groups=groups, bias=False, dilation=dilation)
def conv1x1(in_planes, out_planes, stride=1):
"""1x1 convolution"""
return nn.Conv2d(in_planes, out_planes, kernel_size=1, stride=stride, bias=False)
class BasicBlock(nn.Module):
expansion = 1
def __init__(self, inplanes, planes, stride=1, downsample=None, groups=1,
base_width=64, dilation=1, norm_layer=None):
super(BasicBlock, self).__init__()
if norm_layer is None:
norm_layer = nn.BatchNorm2d
if groups != 1 or base_width != 64:
raise ValueError('BasicBlock only supports groups=1 and base_width=64')
if dilation > 1:
raise NotImplementedError("Dilation > 1 not supported in BasicBlock")
# Both self.conv1 and self.downsample layers downsample the input when stride != 1
self.conv1 = conv3x3(inplanes, planes, stride)
self.bn1 = norm_layer(planes)
self.relu = nn.ReLU(inplace=True)
self.conv2 = conv3x3(planes, planes)
self.bn2 = norm_layer(planes)
self.downsample = downsample
self.stride = stride
def forward(self, x):
identity = 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:
identity = self.downsample(x)
out += identity
out = self.relu(out)
return out
class Bottleneck(nn.Module):
# Bottleneck in torchvision places the stride for downsampling at 3x3 convolution(self.conv2)
# while original implementation places the stride at the first 1x1 convolution(self.conv1)
# according to "Deep residual learning for image recognition"https://arxiv.org/abs/1512.03385.
# This variant is also known as ResNet V1.5 and improves accuracy according to
# https://ngc.nvidia.com/catalog/model-scripts/nvidia:resnet_50_v1_5_for_pytorch.
expansion = 4
def __init__(self, inplanes, planes, stride=1, downsample=None, groups=1,
base_width=64, dilation=1, norm_layer=None):
super(Bottleneck, self).__init__()
if norm_layer is None:
norm_layer = nn.BatchNorm2d
width = int(planes * (base_width / 64.)) * groups
# Both self.conv2 and self.downsample layers downsample the input when stride != 1
self.conv1 = conv1x1(inplanes, width)
self.bn1 = norm_layer(width)
self.conv2 = conv3x3(width, width, stride, groups, dilation)
self.bn2 = norm_layer(width)
self.conv3 = conv1x1(width, planes * self.expansion)
self.bn3 = norm_layer(planes * self.expansion)
self.relu = nn.ReLU(inplace=True)
self.downsample = downsample
self.stride = stride
def forward(self, x):
identity = x
out = self.conv1(x)
out = self.bn1(out)
out = self.relu(out)
out = self.conv2(out)
out = self.bn2(out)
out = self.relu(out)
out = self.conv3(out)
out = self.bn3(out)
if self.downsample is not None:
identity = self.downsample(x)
out += identity
out = self.relu(out)
return out
class ResNet(nn.Module):
def __init__(self, block, layers, num_classes=1000, zero_init_residual=False,
groups=1, width_per_group=64, replace_stride_with_dilation=None,
norm_layer=None):
super(ResNet, self).__init__()
if norm_layer is None:
norm_layer = nn.BatchNorm2d
self._norm_layer = norm_layer
self.inplanes = 64
self.dilation = 1
if replace_stride_with_dilation is None:
# each element in the tuple indicates if we should replace
# the 2x2 stride with a dilated convolution instead
replace_stride_with_dilation = [False, False, False]
if len(replace_stride_with_dilation) != 3:
raise ValueError("replace_stride_with_dilation should be None "
"or a 3-element tuple, got {}".format(replace_stride_with_dilation))
self.groups = groups
self.base_width = width_per_group
self.conv1 = nn.Conv2d(3, self.inplanes, kernel_size=7, stride=2, padding=3,
bias=False)
self.bn1 = 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])
self.layer2 = self._make_layer(block, 128, layers[1], stride=2,
dilate=replace_stride_with_dilation[0])
self.layer3 = self._make_layer(block, 256, layers[2], stride=2,
dilate=replace_stride_with_dilation[1])
self.layer4 = self._make_layer(block, 512, layers[3], stride=2,
dilate=replace_stride_with_dilation[2])
self.avgpool = nn.AdaptiveAvgPool2d((1, 1))
self.fc = nn.Linear(512 * block.expansion, num_classes)
for m in self.modules():
if isinstance(m, nn.Conv2d):
nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
elif isinstance(m, (nn.BatchNorm2d, nn.GroupNorm)):
nn.init.constant_(m.weight, 1)
nn.init.constant_(m.bias, 0)
# Zero-initialize the last BN in each residual branch,
# so that the residual branch starts with zeros, and each residual block behaves like an identity.
# This improves the model by 0.2~0.3% according to https://arxiv.org/abs/1706.02677
if zero_init_residual:
for m in self.modules():
if isinstance(m, Bottleneck):
nn.init.constant_(m.bn3.weight, 0)
elif isinstance(m, BasicBlock):
nn.init.constant_(m.bn2.weight, 0)
def _make_layer(self, block, planes, blocks, stride=1, dilate=False):
norm_layer = self._norm_layer
downsample = None
previous_dilation = self.dilation
if dilate:
self.dilation *= stride
stride = 1
if stride != 1 or self.inplanes != planes * block.expansion:
downsample = nn.Sequential(
conv1x1(self.inplanes, planes * block.expansion, stride),
norm_layer(planes * block.expansion),
)
layers = []
layers.append(block(self.inplanes, planes, stride, downsample, self.groups,
self.base_width, previous_dilation, norm_layer))
self.inplanes = planes * block.expansion
for _ in range(1, blocks):
layers.append(block(self.inplanes, planes, groups=self.groups,
base_width=self.base_width, dilation=self.dilation,
norm_layer=norm_layer))
return nn.Sequential(*layers)
def _forward_impl(self, x):
# See note [TorchScript super()]
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)
x = self.avgpool(x)
x = torch.flatten(x, 1)
x = self.fc(x)
return x
def forward(self, x):
return self._forward_impl(x)
def _resnet(arch, block, layers, pretrained, progress, **kwargs):
model = ResNet(block, layers, **kwargs)
if pretrained:
state_dict = load_state_dict_from_url(model_urls[arch],
progress=progress)
model.load_state_dict(state_dict)
return model
def resnet18(pretrained=False, progress=True, **kwargs):
r"""ResNet-18 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet18', BasicBlock, [2, 2, 2, 2], pretrained, progress,
**kwargs)
def resnet34(pretrained=False, progress=True, **kwargs):
r"""ResNet-34 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet34', BasicBlock, [3, 4, 6, 3], pretrained, progress,
**kwargs)
def resnet50(pretrained=False, progress=True, **kwargs):
r"""ResNet-50 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet50', Bottleneck, [3, 4, 6, 3], pretrained, progress,
**kwargs)
def resnet101(pretrained=False, progress=True, **kwargs):
r"""ResNet-101 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet101', Bottleneck, [3, 4, 23, 3], pretrained, progress,
**kwargs)
def resnet152(pretrained=False, progress=True, **kwargs):
r"""ResNet-152 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet152', Bottleneck, [3, 8, 36, 3], pretrained, progress,
**kwargs)
def resnext50_32x4d(pretrained=False, progress=True, **kwargs):
r"""ResNeXt-50 32x4d model from
`"Aggregated Residual Transformation for Deep Neural Networks" <https://arxiv.org/pdf/1611.05431.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
kwargs['groups'] = 32
kwargs['width_per_group'] = 4
return _resnet('resnext50_32x4d', Bottleneck, [3, 4, 6, 3],
pretrained, progress, **kwargs)
def resnext101_32x8d(pretrained=False, progress=True, **kwargs):
r"""ResNeXt-101 32x8d model from
`"Aggregated Residual Transformation for Deep Neural Networks" <https://arxiv.org/pdf/1611.05431.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
kwargs['groups'] = 32
kwargs['width_per_group'] = 8
return _resnet('resnext101_32x8d', Bottleneck, [3, 4, 23, 3],
pretrained, progress, **kwargs)
def wide_resnet50_2(pretrained=False, progress=True, **kwargs):
r"""Wide ResNet-50-2 model from
`"Wide Residual Networks" <https://arxiv.org/pdf/1605.07146.pdf>`_
The model is the same as ResNet except for the bottleneck number of channels
which is twice larger in every block. The number of channels in outer 1x1
convolutions is the same, e.g. last block in ResNet-50 has 2048-512-2048
channels, and in Wide ResNet-50-2 has 2048-1024-2048.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
kwargs['width_per_group'] = 64 * 2
return _resnet('wide_resnet50_2', Bottleneck, [3, 4, 6, 3],
pretrained, progress, **kwargs)
def wide_resnet101_2(pretrained=False, progress=True, **kwargs):
r"""Wide ResNet-101-2 model from
`"Wide Residual Networks" <https://arxiv.org/pdf/1605.07146.pdf>`_
The model is the same as ResNet except for the bottleneck number of channels
which is twice larger in every block. The number of channels in outer 1x1
convolutions is the same, e.g. last block in ResNet-50 has 2048-512-2048
channels, and in Wide ResNet-50-2 has 2048-1024-2048.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
kwargs['width_per_group'] = 64 * 2
return _resnet('wide_resnet101_2', Bottleneck, [3, 4, 23, 3],
pretrained, progress, **kwargs)Introduced by Krizhevsky et al. in ImageNet Classification with Deep Convolutional Neural Networks
AlexNet is a classic convolutional neural network architecture. It consists of convolutions, max pooling and dense layers as the basic building blocks. Grouped convolutions are used in order to fit the model across two GPUs.
Source: Technical Paper - ImageNet Classification with Deep Convolutional Neural Networks
[AlexNet]{https://d2l.ai/chapter_convolutional-modern/alexnet.html?highlight=alexnet
"""
Implementation of AlexNet, from paper
"ImageNet Classification with Deep Convolutional Neural Networks" by Alex Krizhevsky et al.
See: https://papers.nips.cc/paper/4824-imagenet-classification-with-deep-convolutional-neural-networks.pdf
"""
import os
import torch
import torch.nn as nn
import torch.optim as optim
import torch.nn.functional as F
from torch.utils import data
import torchvision.datasets as datasets
import torchvision.transforms as transforms
from tensorboardX import SummaryWriter
# define pytorch device - useful for device-agnostic execution
device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
# define model parameters
NUM_EPOCHS = 90 # original paper
BATCH_SIZE = 128
MOMENTUM = 0.9
LR_DECAY = 0.0005
LR_INIT = 0.01
IMAGE_DIM = 227 # pixels
NUM_CLASSES = 1000 # 1000 classes for imagenet 2012 dataset
DEVICE_IDS = [0, 1, 2, 3] # GPUs to use
# modify this to point to your data directory
INPUT_ROOT_DIR = 'alexnet_data_in'
TRAIN_IMG_DIR = 'alexnet_data_in/imagenet'
OUTPUT_DIR = 'alexnet_data_out'
LOG_DIR = OUTPUT_DIR + '/tblogs' # tensorboard logs
CHECKPOINT_DIR = OUTPUT_DIR + '/models' # model checkpoints
# make checkpoint path directory
os.makedirs(CHECKPOINT_DIR, exist_ok=True)
class AlexNet(nn.Module):
"""
Neural network model consisting of layers propsed by AlexNet paper.
"""
def __init__(self, num_classes=1000):
"""
Define and allocate layers for this neural net.
Args:
num_classes (int): number of classes to predict with this model
"""
super().__init__()
# input size should be : (b x 3 x 227 x 227)
# The image in the original paper states that width and height are 224 pixels, but
# the dimensions after first convolution layer do not lead to 55 x 55.
self.net = nn.Sequential(
nn.Conv2d(in_channels=3, out_channels=96, kernel_size=11, stride=4), # (b x 96 x 55 x 55)
nn.ReLU(),
nn.LocalResponseNorm(size=5, alpha=0.0001, beta=0.75, k=2), # section 3.3
nn.MaxPool2d(kernel_size=3, stride=2), # (b x 96 x 27 x 27)
nn.Conv2d(96, 256, 5, padding=2), # (b x 256 x 27 x 27)
nn.ReLU(),
nn.LocalResponseNorm(size=5, alpha=0.0001, beta=0.75, k=2),
nn.MaxPool2d(kernel_size=3, stride=2), # (b x 256 x 13 x 13)
nn.Conv2d(256, 384, 3, padding=1), # (b x 384 x 13 x 13)
nn.ReLU(),
nn.Conv2d(384, 384, 3, padding=1), # (b x 384 x 13 x 13)
nn.ReLU(),
nn.Conv2d(384, 256, 3, padding=1), # (b x 256 x 13 x 13)
nn.ReLU(),
nn.MaxPool2d(kernel_size=3, stride=2), # (b x 256 x 6 x 6)
)
# classifier is just a name for linear layers
self.classifier = nn.Sequential(
nn.Dropout(p=0.5, inplace=True),
nn.Linear(in_features=(256 * 6 * 6), out_features=4096),
nn.ReLU(),
nn.Dropout(p=0.5, inplace=True),
nn.Linear(in_features=4096, out_features=4096),
nn.ReLU(),
nn.Linear(in_features=4096, out_features=num_classes),
)
self.init_bias() # initialize bias
def init_bias(self):
for layer in self.net:
if isinstance(layer, nn.Conv2d):
nn.init.normal_(layer.weight, mean=0, std=0.01)
nn.init.constant_(layer.bias, 0)
# original paper = 1 for Conv2d layers 2nd, 4th, and 5th conv layers
nn.init.constant_(self.net[4].bias, 1)
nn.init.constant_(self.net[10].bias, 1)
nn.init.constant_(self.net[12].bias, 1)
def forward(self, x):
"""
Pass the input through the net.
Args:
x (Tensor): input tensor
Returns:
output (Tensor): output tensor
"""
x = self.net(x)
x = x.view(-1, 256 * 6 * 6) # reduce the dimensions for linear layer input
return self.classifier(x)
if __name__ == '__main__':
# print the seed value
seed = torch.initial_seed()
print('Used seed : {}'.format(seed))
tbwriter = SummaryWriter(log_dir=LOG_DIR)
print('TensorboardX summary writer created')
# create model
alexnet = AlexNet(num_classes=NUM_CLASSES).to(device)
# train on multiple GPUs
alexnet = torch.nn.parallel.DataParallel(alexnet, device_ids=DEVICE_IDS)
print(alexnet)
print('AlexNet created')
# create dataset and data loader
dataset = datasets.ImageFolder(TRAIN_IMG_DIR, transforms.Compose([
# transforms.RandomResizedCrop(IMAGE_DIM, scale=(0.9, 1.0), ratio=(0.9, 1.1)),
transforms.CenterCrop(IMAGE_DIM),
# transforms.RandomHorizontalFlip(),
transforms.ToTensor(),
transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]),
]))
print('Dataset created')
dataloader = data.DataLoader(
dataset,
shuffle=True,
pin_memory=True,
num_workers=8,
drop_last=True,
batch_size=BATCH_SIZE)
print('Dataloader created')
# create optimizer
# the one that WORKS
optimizer = optim.Adam(params=alexnet.parameters(), lr=0.0001)
### BELOW is the setting proposed by the original paper - which doesn't train....
# optimizer = optim.SGD(
# params=alexnet.parameters(),
# lr=LR_INIT,
# momentum=MOMENTUM,
# weight_decay=LR_DECAY)
print('Optimizer created')
# multiply LR by 1 / 10 after every 30 epochs
lr_scheduler = optim.lr_scheduler.StepLR(optimizer, step_size=30, gamma=0.1)
print('LR Scheduler created')
# start training!!
print('Starting training...')
total_steps = 1
for epoch in range(NUM_EPOCHS):
lr_scheduler.step()
for imgs, classes in dataloader:
imgs, classes = imgs.to(device), classes.to(device)
# calculate the loss
output = alexnet(imgs)
loss = F.cross_entropy(output, classes)
# update the parameters
optimizer.zero_grad()
loss.backward()
optimizer.step()
# log the information and add to tensorboard
if total_steps % 10 == 0:
with torch.no_grad():
_, preds = torch.max(output, 1)
accuracy = torch.sum(preds == classes)
print('Epoch: {} \tStep: {} \tLoss: {:.4f} \tAcc: {}'
.format(epoch + 1, total_steps, loss.item(), accuracy.item()))
tbwriter.add_scalar('loss', loss.item(), total_steps)
tbwriter.add_scalar('accuracy', accuracy.item(), total_steps)
# print out gradient values and parameter average values
if total_steps % 100 == 0:
with torch.no_grad():
# print and save the grad of the parameters
# also print and save parameter values
print('*' * 10)
for name, parameter in alexnet.named_parameters():
if parameter.grad is not None:
avg_grad = torch.mean(parameter.grad)
print('\t{} - grad_avg: {}'.format(name, avg_grad))
tbwriter.add_scalar('grad_avg/{}'.format(name), avg_grad.item(), total_steps)
tbwriter.add_histogram('grad/{}'.format(name),
parameter.grad.cpu().numpy(), total_steps)
if parameter.data is not None:
avg_weight = torch.mean(parameter.data)
print('\t{} - param_avg: {}'.format(name, avg_weight))
tbwriter.add_histogram('weight/{}'.format(name),
parameter.data.cpu().numpy(), total_steps)
tbwriter.add_scalar('weight_avg/{}'.format(name), avg_weight.item(), total_steps)
total_steps += 1
# save checkpoints
checkpoint_path = os.path.join(CHECKPOINT_DIR, 'alexnet_states_e{}.pkl'.format(epoch + 1))
state = {
'epoch': epoch,
'total_steps': total_steps,
'optimizer': optimizer.state_dict(),
'model': alexnet.state_dict(),
'seed': seed,
}
torch.save(state, checkpoint_path)Introduced by Simonyan et al. in Very Deep Convolutional Networks for Large-Scale Image Recognition
.png)
VGG is a classical convolutional neural network architecture. It was based on an analysis of how to increase the depth of such networks. The network utilises small 3 x 3 filters. Otherwise the network is characterized by its simplicity: the only other components being pooling layers and a fully connected layer.
Image: Davi Frossard
Source: Very Deep Convolutional Networks for Large-Scale Image Recognition
import torch
import torch.nn as nn
from .utils import load_state_dict_from_url
__all__ = [
'VGG', 'vgg11', 'vgg11_bn', 'vgg13', 'vgg13_bn', 'vgg16', 'vgg16_bn',
'vgg19_bn', 'vgg19',
]
model_urls = {
'vgg11': 'https://download.pytorch.org/models/vgg11-bbd30ac9.pth',
'vgg13': 'https://download.pytorch.org/models/vgg13-c768596a.pth',
'vgg16': 'https://download.pytorch.org/models/vgg16-397923af.pth',
'vgg19': 'https://download.pytorch.org/models/vgg19-dcbb9e9d.pth',
'vgg11_bn': 'https://download.pytorch.org/models/vgg11_bn-6002323d.pth',
'vgg13_bn': 'https://download.pytorch.org/models/vgg13_bn-abd245e5.pth',
'vgg16_bn': 'https://download.pytorch.org/models/vgg16_bn-6c64b313.pth',
'vgg19_bn': 'https://download.pytorch.org/models/vgg19_bn-c79401a0.pth',
}
class VGG(nn.Module):
def __init__(self, features, num_classes=1000, init_weights=True):
super(VGG, self).__init__()
self.features = features
self.avgpool = nn.AdaptiveAvgPool2d((7, 7))
self.classifier = nn.Sequential(
nn.Linear(512 * 7 * 7, 4096),
nn.ReLU(True),
nn.Dropout(),
nn.Linear(4096, 4096),
nn.ReLU(True),
nn.Dropout(),
nn.Linear(4096, num_classes),
)
if init_weights:
self._initialize_weights()
def forward(self, x):
x = self.features(x)
x = self.avgpool(x)
x = torch.flatten(x, 1)
x = self.classifier(x)
return x
def _initialize_weights(self):
for m in self.modules():
if isinstance(m, nn.Conv2d):
nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
if m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.BatchNorm2d):
nn.init.constant_(m.weight, 1)
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.Linear):
nn.init.normal_(m.weight, 0, 0.01)
nn.init.constant_(m.bias, 0)
def make_layers(cfg, batch_norm=False):
layers = []
in_channels = 3
for v in cfg:
if v == 'M':
layers += [nn.MaxPool2d(kernel_size=2, stride=2)]
else:
conv2d = nn.Conv2d(in_channels, v, kernel_size=3, padding=1)
if batch_norm:
layers += [conv2d, nn.BatchNorm2d(v), nn.ReLU(inplace=True)]
else:
layers += [conv2d, nn.ReLU(inplace=True)]
in_channels = v
return nn.Sequential(*layers)
cfgs = {
'A': [64, 'M', 128, 'M', 256, 256, 'M', 512, 512, 'M', 512, 512, 'M'],
'B': [64, 64, 'M', 128, 128, 'M', 256, 256, 'M', 512, 512, 'M', 512, 512, 'M'],
'D': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 'M', 512, 512, 512, 'M', 512, 512, 512, 'M'],
'E': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 256, 'M', 512, 512, 512, 512, 'M', 512, 512, 512, 512, 'M'],
}
def _vgg(arch, cfg, batch_norm, pretrained, progress, **kwargs):
if pretrained:
kwargs['init_weights'] = False
model = VGG(make_layers(cfgs[cfg], batch_norm=batch_norm), **kwargs)
if pretrained:
state_dict = load_state_dict_from_url(model_urls[arch],
progress=progress)
model.load_state_dict(state_dict)
return model
def vgg11(pretrained=False, progress=True, **kwargs):
r"""VGG 11-layer model (configuration "A") from
`"Very Deep Convolutional Networks For Large-Scale Image Recognition" <https://arxiv.org/pdf/1409.1556.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _vgg('vgg11', 'A', False, pretrained, progress, **kwargs)
def vgg11_bn(pretrained=False, progress=True, **kwargs):
r"""VGG 11-layer model (configuration "A") with batch normalization
`"Very Deep Convolutional Networks For Large-Scale Image Recognition" <https://arxiv.org/pdf/1409.1556.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _vgg('vgg11_bn', 'A', True, pretrained, progress, **kwargs)
def vgg13(pretrained=False, progress=True, **kwargs):
r"""VGG 13-layer model (configuration "B")
`"Very Deep Convolutional Networks For Large-Scale Image Recognition" <https://arxiv.org/pdf/1409.1556.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _vgg('vgg13', 'B', False, pretrained, progress, **kwargs)
def vgg13_bn(pretrained=False, progress=True, **kwargs):
r"""VGG 13-layer model (configuration "B") with batch normalization
`"Very Deep Convolutional Networks For Large-Scale Image Recognition" <https://arxiv.org/pdf/1409.1556.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _vgg('vgg13_bn', 'B', True, pretrained, progress, **kwargs)
def vgg16(pretrained=False, progress=True, **kwargs):
r"""VGG 16-layer model (configuration "D")
`"Very Deep Convolutional Networks For Large-Scale Image Recognition" <https://arxiv.org/pdf/1409.1556.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _vgg('vgg16', 'D', False, pretrained, progress, **kwargs)
def vgg16_bn(pretrained=False, progress=True, **kwargs):
r"""VGG 16-layer model (configuration "D") with batch normalization
`"Very Deep Convolutional Networks For Large-Scale Image Recognition" <https://arxiv.org/pdf/1409.1556.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _vgg('vgg16_bn', 'D', True, pretrained, progress, **kwargs)
def vgg19(pretrained=False, progress=True, **kwargs):
r"""VGG 19-layer model (configuration "E")
`"Very Deep Convolutional Networks For Large-Scale Image Recognition" <https://arxiv.org/pdf/1409.1556.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _vgg('vgg19', 'E', False, pretrained, progress, **kwargs)
def vgg19_bn(pretrained=False, progress=True, **kwargs):
r"""VGG 19-layer model (configuration 'E') with batch normalization
`"Very Deep Convolutional Networks For Large-Scale Image Recognition" <https://arxiv.org/pdf/1409.1556.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _vgg('vgg19_bn', 'E', True, pretrained, progress, **kwargs)Introduced by Huang et al. in Densely Connected Convolutional Networks
A DenseNet is a type of convolutional neural network that utilises dense connections between layers, through Dense Blocks, where we connect all layers (with matching feature-map sizes) directly with each other. To preserve the feed-forward nature, each layer obtains additional inputs from all preceding layers and passes on its own feature-maps to all subsequent layers.
Source: Densely Connected Convolutional Networks
import re
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.utils.checkpoint as cp
from collections import OrderedDict
from .utils import load_state_dict_from_url
from torch import Tensor
from torch.jit.annotations import List
__all__ = ['DenseNet', 'densenet121', 'densenet169', 'densenet201', 'densenet161']
model_urls = {
'densenet121': 'https://download.pytorch.org/models/densenet121-a639ec97.pth',
'densenet169': 'https://download.pytorch.org/models/densenet169-b2777c0a.pth',
'densenet201': 'https://download.pytorch.org/models/densenet201-c1103571.pth',
'densenet161': 'https://download.pytorch.org/models/densenet161-8d451a50.pth',
}
class _DenseLayer(nn.Module):
def __init__(self, num_input_features, growth_rate, bn_size, drop_rate, memory_efficient=False):
super(_DenseLayer, self).__init__()
self.add_module('norm1', nn.BatchNorm2d(num_input_features)),
self.add_module('relu1', nn.ReLU(inplace=True)),
self.add_module('conv1', nn.Conv2d(num_input_features, bn_size *
growth_rate, kernel_size=1, stride=1,
bias=False)),
self.add_module('norm2', nn.BatchNorm2d(bn_size * growth_rate)),
self.add_module('relu2', nn.ReLU(inplace=True)),
self.add_module('conv2', nn.Conv2d(bn_size * growth_rate, growth_rate,
kernel_size=3, stride=1, padding=1,
bias=False)),
self.drop_rate = float(drop_rate)
self.memory_efficient = memory_efficient
def bn_function(self, inputs):
# type: (List[Tensor]) -> Tensor
concated_features = torch.cat(inputs, 1)
bottleneck_output = self.conv1(self.relu1(self.norm1(concated_features))) # noqa: T484
return bottleneck_output
# todo: rewrite when torchscript supports any
def any_requires_grad(self, input):
# type: (List[Tensor]) -> bool
for tensor in input:
if tensor.requires_grad:
return True
return False
@torch.jit.unused # noqa: T484
def call_checkpoint_bottleneck(self, input):
# type: (List[Tensor]) -> Tensor
def closure(*inputs):
return self.bn_function(inputs)
return cp.checkpoint(closure, *input)
@torch.jit._overload_method # noqa: F811
def forward(self, input):
# type: (List[Tensor]) -> (Tensor)
pass
@torch.jit._overload_method # noqa: F811
def forward(self, input):
# type: (Tensor) -> (Tensor)
pass
# torchscript does not yet support *args, so we overload method
# allowing it to take either a List[Tensor] or single Tensor
def forward(self, input): # noqa: F811
if isinstance(input, Tensor):
prev_features = [input]
else:
prev_features = input
if self.memory_efficient and self.any_requires_grad(prev_features):
if torch.jit.is_scripting():
raise Exception("Memory Efficient not supported in JIT")
bottleneck_output = self.call_checkpoint_bottleneck(prev_features)
else:
bottleneck_output = self.bn_function(prev_features)
new_features = self.conv2(self.relu2(self.norm2(bottleneck_output)))
if self.drop_rate > 0:
new_features = F.dropout(new_features, p=self.drop_rate,
training=self.training)
return new_features
class _DenseBlock(nn.ModuleDict):
_version = 2
def __init__(self, num_layers, num_input_features, bn_size, growth_rate, drop_rate, memory_efficient=False):
super(_DenseBlock, self).__init__()
for i in range(num_layers):
layer = _DenseLayer(
num_input_features + i * growth_rate,
growth_rate=growth_rate,
bn_size=bn_size,
drop_rate=drop_rate,
memory_efficient=memory_efficient,
)
self.add_module('denselayer%d' % (i + 1), layer)
def forward(self, init_features):
features = [init_features]
for name, layer in self.items():
new_features = layer(features)
features.append(new_features)
return torch.cat(features, 1)
class _Transition(nn.Sequential):
def __init__(self, num_input_features, num_output_features):
super(_Transition, self).__init__()
self.add_module('norm', nn.BatchNorm2d(num_input_features))
self.add_module('relu', nn.ReLU(inplace=True))
self.add_module('conv', nn.Conv2d(num_input_features, num_output_features,
kernel_size=1, stride=1, bias=False))
self.add_module('pool', nn.AvgPool2d(kernel_size=2, stride=2))
class DenseNet(nn.Module):
r"""Densenet-BC model class, based on
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_
Args:
growth_rate (int) - how many filters to add each layer (`k` in paper)
block_config (list of 4 ints) - how many layers in each pooling block
num_init_features (int) - the number of filters to learn in the first convolution layer
bn_size (int) - multiplicative factor for number of bottle neck layers
(i.e. bn_size * k features in the bottleneck layer)
drop_rate (float) - dropout rate after each dense layer
num_classes (int) - number of classification classes
memory_efficient (bool) - If True, uses checkpointing. Much more memory efficient,
but slower. Default: *False*. See `"paper" <https://arxiv.org/pdf/1707.06990.pdf>`_
"""
def __init__(self, growth_rate=32, block_config=(6, 12, 24, 16),
num_init_features=64, bn_size=4, drop_rate=0, num_classes=1000, memory_efficient=False):
super(DenseNet, self).__init__()
# First convolution
self.features = nn.Sequential(OrderedDict([
('conv0', nn.Conv2d(3, num_init_features, kernel_size=7, stride=2,
padding=3, bias=False)),
('norm0', nn.BatchNorm2d(num_init_features)),
('relu0', nn.ReLU(inplace=True)),
('pool0', nn.MaxPool2d(kernel_size=3, stride=2, padding=1)),
]))
# Each denseblock
num_features = num_init_features
for i, num_layers in enumerate(block_config):
block = _DenseBlock(
num_layers=num_layers,
num_input_features=num_features,
bn_size=bn_size,
growth_rate=growth_rate,
drop_rate=drop_rate,
memory_efficient=memory_efficient
)
self.features.add_module('denseblock%d' % (i + 1), block)
num_features = num_features + num_layers * growth_rate
if i != len(block_config) - 1:
trans = _Transition(num_input_features=num_features,
num_output_features=num_features // 2)
self.features.add_module('transition%d' % (i + 1), trans)
num_features = num_features // 2
# Final batch norm
self.features.add_module('norm5', nn.BatchNorm2d(num_features))
# Linear layer
self.classifier = nn.Linear(num_features, num_classes)
# Official init from torch repo.
for m in self.modules():
if isinstance(m, nn.Conv2d):
nn.init.kaiming_normal_(m.weight)
elif isinstance(m, nn.BatchNorm2d):
nn.init.constant_(m.weight, 1)
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.Linear):
nn.init.constant_(m.bias, 0)
def forward(self, x):
features = self.features(x)
out = F.relu(features, inplace=True)
out = F.adaptive_avg_pool2d(out, (1, 1))
out = torch.flatten(out, 1)
out = self.classifier(out)
return out
def _load_state_dict(model, model_url, progress):
# '.'s are no longer allowed in module names, but previous _DenseLayer
# has keys 'norm.1', 'relu.1', 'conv.1', 'norm.2', 'relu.2', 'conv.2'.
# They are also in the checkpoints in model_urls. This pattern is used
# to find such keys.
pattern = re.compile(
r'^(.*denselayer\d+\.(?:norm|relu|conv))\.((?:[12])\.(?:weight|bias|running_mean|running_var))$')
state_dict = load_state_dict_from_url(model_url, progress=progress)
for key in list(state_dict.keys()):
res = pattern.match(key)
if res:
new_key = res.group(1) + res.group(2)
state_dict[new_key] = state_dict[key]
del state_dict[key]
model.load_state_dict(state_dict)
def _densenet(arch, growth_rate, block_config, num_init_features, pretrained, progress,
**kwargs):
model = DenseNet(growth_rate, block_config, num_init_features, **kwargs)
if pretrained:
_load_state_dict(model, model_urls[arch], progress)
return model
def densenet121(pretrained=False, progress=True, **kwargs):
r"""Densenet-121 model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
memory_efficient (bool) - If True, uses checkpointing. Much more memory efficient,
but slower. Default: *False*. See `"paper" <https://arxiv.org/pdf/1707.06990.pdf>`_
"""
return _densenet('densenet121', 32, (6, 12, 24, 16), 64, pretrained, progress,
**kwargs)
def densenet161(pretrained=False, progress=True, **kwargs):
r"""Densenet-161 model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
memory_efficient (bool) - If True, uses checkpointing. Much more memory efficient,
but slower. Default: *False*. See `"paper" <https://arxiv.org/pdf/1707.06990.pdf>`_
"""
return _densenet('densenet161', 48, (6, 12, 36, 24), 96, pretrained, progress,
**kwargs)
def densenet169(pretrained=False, progress=True, **kwargs):
r"""Densenet-169 model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
memory_efficient (bool) - If True, uses checkpointing. Much more memory efficient,
but slower. Default: *False*. See `"paper" <https://arxiv.org/pdf/1707.06990.pdf>`_
"""
return _densenet('densenet169', 32, (6, 12, 32, 32), 64, pretrained, progress,
**kwargs)
def densenet201(pretrained=False, progress=True, **kwargs):
r"""Densenet-201 model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
memory_efficient (bool) - If True, uses checkpointing. Much more memory efficient,
but slower. Default: *False*. See `"paper" <https://arxiv.org/pdf/1707.06990.pdf>`_
"""
return _densenet('densenet201', 32, (6, 12, 48, 32), 64, pretrained, progress,
**kwargs)Introduced by Sandler et al. in MobileNetV2: Inverted Residuals and Linear Bottlenecks
MobileNetV2 is a convolutional neural network architecture that seeks to perform well on mobile devices. It is based on an inverted residual structure where the residual connections are between the bottleneck layers. The intermediate expansion layer uses lightweight depthwise convolutions to filter features as a source of non-linearity. As a whole, the architecture of MobileNetV2 contains the initial fully convolution layer with 32 filters, followed by 19 residual bottleneck layers.
Source: MobileNetV2: Inverted Residuals and Linear Bottlenecks
from torch import nn
from .utils import load_state_dict_from_url
__all__ = ['MobileNetV2', 'mobilenet_v2']
model_urls = {
'mobilenet_v2': 'https://download.pytorch.org/models/mobilenet_v2-b0353104.pth',
}
def _make_divisible(v, divisor, min_value=None):
"""
This function is taken from the original tf repo.
It ensures that all layers have a channel number that is divisible by 8
It can be seen here:
https://github.com/tensorflow/models/blob/master/research/slim/nets/mobilenet/mobilenet.py
:param v:
:param divisor:
:param min_value:
:return:
"""
if min_value is None:
min_value = divisor
new_v = max(min_value, int(v + divisor / 2) // divisor * divisor)
# Make sure that round down does not go down by more than 10%.
if new_v < 0.9 * v:
new_v += divisor
return new_v
class ConvBNReLU(nn.Sequential):
def __init__(self, in_planes, out_planes, kernel_size=3, stride=1, groups=1, norm_layer=None):
padding = (kernel_size - 1) // 2
if norm_layer is None:
norm_layer = nn.BatchNorm2d
super(ConvBNReLU, self).__init__(
nn.Conv2d(in_planes, out_planes, kernel_size, stride, padding, groups=groups, bias=False),
norm_layer(out_planes),
nn.ReLU6(inplace=True)
)
class InvertedResidual(nn.Module):
def __init__(self, inp, oup, stride, expand_ratio, norm_layer=None):
super(InvertedResidual, self).__init__()
self.stride = stride
assert stride in [1, 2]
if norm_layer is None:
norm_layer = nn.BatchNorm2d
hidden_dim = int(round(inp * expand_ratio))
self.use_res_connect = self.stride == 1 and inp == oup
layers = []
if expand_ratio != 1:
# pw
layers.append(ConvBNReLU(inp, hidden_dim, kernel_size=1, norm_layer=norm_layer))
layers.extend([
# dw
ConvBNReLU(hidden_dim, hidden_dim, stride=stride, groups=hidden_dim, norm_layer=norm_layer),
# pw-linear
nn.Conv2d(hidden_dim, oup, 1, 1, 0, bias=False),
norm_layer(oup),
])
self.conv = nn.Sequential(*layers)
def forward(self, x):
if self.use_res_connect:
return x + self.conv(x)
else:
return self.conv(x)
class MobileNetV2(nn.Module):
def __init__(self,
num_classes=1000,
width_mult=1.0,
inverted_residual_setting=None,
round_nearest=8,
block=None,
norm_layer=None):
"""
MobileNet V2 main class
Args:
num_classes (int): Number of classes
width_mult (float): Width multiplier - adjusts number of channels in each layer by this amount
inverted_residual_setting: Network structure
round_nearest (int): Round the number of channels in each layer to be a multiple of this number
Set to 1 to turn off rounding
block: Module specifying inverted residual building block for mobilenet
norm_layer: Module specifying the normalization layer to use
"""
super(MobileNetV2, self).__init__()
if block is None:
block = InvertedResidual
if norm_layer is None:
norm_layer = nn.BatchNorm2d
input_channel = 32
last_channel = 1280
if inverted_residual_setting is None:
inverted_residual_setting = [
# t, c, n, s
[1, 16, 1, 1],
[6, 24, 2, 2],
[6, 32, 3, 2],
[6, 64, 4, 2],
[6, 96, 3, 1],
[6, 160, 3, 2],
[6, 320, 1, 1],
]
# only check the first element, assuming user knows t,c,n,s are required
if len(inverted_residual_setting) == 0 or len(inverted_residual_setting[0]) != 4:
raise ValueError("inverted_residual_setting should be non-empty "
"or a 4-element list, got {}".format(inverted_residual_setting))
# building first layer
input_channel = _make_divisible(input_channel * width_mult, round_nearest)
self.last_channel = _make_divisible(last_channel * max(1.0, width_mult), round_nearest)
features = [ConvBNReLU(3, input_channel, stride=2, norm_layer=norm_layer)]
# building inverted residual blocks
for t, c, n, s in inverted_residual_setting:
output_channel = _make_divisible(c * width_mult, round_nearest)
for i in range(n):
stride = s if i == 0 else 1
features.append(block(input_channel, output_channel, stride, expand_ratio=t, norm_layer=norm_layer))
input_channel = output_channel
# building last several layers
features.append(ConvBNReLU(input_channel, self.last_channel, kernel_size=1, norm_layer=norm_layer))
# make it nn.Sequential
self.features = nn.Sequential(*features)
# building classifier
self.classifier = nn.Sequential(
nn.Dropout(0.2),
nn.Linear(self.last_channel, num_classes),
)
# weight initialization
for m in self.modules():
if isinstance(m, nn.Conv2d):
nn.init.kaiming_normal_(m.weight, mode='fan_out')
if m.bias is not None:
nn.init.zeros_(m.bias)
elif isinstance(m, (nn.BatchNorm2d, nn.GroupNorm)):
nn.init.ones_(m.weight)
nn.init.zeros_(m.bias)
elif isinstance(m, nn.Linear):
nn.init.normal_(m.weight, 0, 0.01)
nn.init.zeros_(m.bias)
def _forward_impl(self, x):
# This exists since TorchScript doesn't support inheritance, so the superclass method
# (this one) needs to have a name other than `forward` that can be accessed in a subclass
x = self.features(x)
# Cannot use "squeeze" as batch-size can be 1 => must use reshape with x.shape[0]
x = nn.functional.adaptive_avg_pool2d(x, 1).reshape(x.shape[0], -1)
x = self.classifier(x)
return x
def forward(self, x):
return self._forward_impl(x)
def mobilenet_v2(pretrained=False, progress=True, **kwargs):
"""
Constructs a MobileNetV2 architecture from
`"MobileNetV2: Inverted Residuals and Linear Bottlenecks" <https://arxiv.org/abs/1801.04381>`_.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
model = MobileNetV2(**kwargs)
if pretrained:
state_dict = load_state_dict_from_url(model_urls['mobilenet_v2'],
progress=progress)
model.load_state_dict(state_dict)
return modelGoogLeNet Introduced by Szegedy et al. in Going Deeper with Convolutions
GoogLeNet is a type of convolutional neural network based on the Inception architecture. It utilises Inception modules, which allow the network to choose between multiple convolutional filter sizes in each block. An Inception network stacks these modules on top of each other, with occasional max-pooling layers with stride 2 to halve the resolution of the grid.
Source: Going Deeper with Convolutions
import warnings
from collections import namedtuple
import torch
import torch.nn as nn
import torch.nn.functional as F
from torch.jit.annotations import Optional, Tuple
from torch import Tensor
from .utils import load_state_dict_from_url
__all__ = ['GoogLeNet', 'googlenet', "GoogLeNetOutputs", "_GoogLeNetOutputs"]
model_urls = {
# GoogLeNet ported from TensorFlow
'googlenet': 'https://download.pytorch.org/models/googlenet-1378be20.pth',
}
GoogLeNetOutputs = namedtuple('GoogLeNetOutputs', ['logits', 'aux_logits2', 'aux_logits1'])
GoogLeNetOutputs.__annotations__ = {'logits': Tensor, 'aux_logits2': Optional[Tensor],
'aux_logits1': Optional[Tensor]}
# Script annotations failed with _GoogleNetOutputs = namedtuple ...
# _GoogLeNetOutputs set here for backwards compat
_GoogLeNetOutputs = GoogLeNetOutputs
def googlenet(pretrained=False, progress=True, **kwargs):
r"""GoogLeNet (Inception v1) model architecture from
`"Going Deeper with Convolutions" <http://arxiv.org/abs/1409.4842>`_.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
aux_logits (bool): If True, adds two auxiliary branches that can improve training.
Default: *False* when pretrained is True otherwise *True*
transform_input (bool): If True, preprocesses the input according to the method with which it
was trained on ImageNet. Default: *False*
"""
if pretrained:
if 'transform_input' not in kwargs:
kwargs['transform_input'] = True
if 'aux_logits' not in kwargs:
kwargs['aux_logits'] = False
if kwargs['aux_logits']:
warnings.warn('auxiliary heads in the pretrained googlenet model are NOT pretrained, '
'so make sure to train them')
original_aux_logits = kwargs['aux_logits']
kwargs['aux_logits'] = True
kwargs['init_weights'] = False
model = GoogLeNet(**kwargs)
state_dict = load_state_dict_from_url(model_urls['googlenet'],
progress=progress)
model.load_state_dict(state_dict)
if not original_aux_logits:
model.aux_logits = False
model.aux1 = None
model.aux2 = None
return model
return GoogLeNet(**kwargs)
class GoogLeNet(nn.Module):
__constants__ = ['aux_logits', 'transform_input']
def __init__(self, num_classes=1000, aux_logits=True, transform_input=False, init_weights=None,
blocks=None):
super(GoogLeNet, self).__init__()
if blocks is None:
blocks = [BasicConv2d, Inception, InceptionAux]
if init_weights is None:
warnings.warn('The default weight initialization of GoogleNet will be changed in future releases of '
'torchvision. If you wish to keep the old behavior (which leads to long initialization times'
' due to scipy/scipy#11299), please set init_weights=True.', FutureWarning)
init_weights = True
assert len(blocks) == 3
conv_block = blocks[0]
inception_block = blocks[1]
inception_aux_block = blocks[2]
self.aux_logits = aux_logits
self.transform_input = transform_input
self.conv1 = conv_block(3, 64, kernel_size=7, stride=2, padding=3)
self.maxpool1 = nn.MaxPool2d(3, stride=2, ceil_mode=True)
self.conv2 = conv_block(64, 64, kernel_size=1)
self.conv3 = conv_block(64, 192, kernel_size=3, padding=1)
self.maxpool2 = nn.MaxPool2d(3, stride=2, ceil_mode=True)
self.inception3a = inception_block(192, 64, 96, 128, 16, 32, 32)
self.inception3b = inception_block(256, 128, 128, 192, 32, 96, 64)
self.maxpool3 = nn.MaxPool2d(3, stride=2, ceil_mode=True)
self.inception4a = inception_block(480, 192, 96, 208, 16, 48, 64)
self.inception4b = inception_block(512, 160, 112, 224, 24, 64, 64)
self.inception4c = inception_block(512, 128, 128, 256, 24, 64, 64)
self.inception4d = inception_block(512, 112, 144, 288, 32, 64, 64)
self.inception4e = inception_block(528, 256, 160, 320, 32, 128, 128)
self.maxpool4 = nn.MaxPool2d(2, stride=2, ceil_mode=True)
self.inception5a = inception_block(832, 256, 160, 320, 32, 128, 128)
self.inception5b = inception_block(832, 384, 192, 384, 48, 128, 128)
if aux_logits:
self.aux1 = inception_aux_block(512, num_classes)
self.aux2 = inception_aux_block(528, num_classes)
else:
self.aux1 = None
self.aux2 = None
self.avgpool = nn.AdaptiveAvgPool2d((1, 1))
self.dropout = nn.Dropout(0.2)
self.fc = nn.Linear(1024, num_classes)
if init_weights:
self._initialize_weights()
def _initialize_weights(self):
for m in self.modules():
if isinstance(m, nn.Conv2d) or isinstance(m, nn.Linear):
import scipy.stats as stats
X = stats.truncnorm(-2, 2, scale=0.01)
values = torch.as_tensor(X.rvs(m.weight.numel()), dtype=m.weight.dtype)
values = values.view(m.weight.size())
with torch.no_grad():
m.weight.copy_(values)
elif isinstance(m, nn.BatchNorm2d):
nn.init.constant_(m.weight, 1)
nn.init.constant_(m.bias, 0)
def _transform_input(self, x):
# type: (Tensor) -> Tensor
if self.transform_input:
x_ch0 = torch.unsqueeze(x[:, 0], 1) * (0.229 / 0.5) + (0.485 - 0.5) / 0.5
x_ch1 = torch.unsqueeze(x[:, 1], 1) * (0.224 / 0.5) + (0.456 - 0.5) / 0.5
x_ch2 = torch.unsqueeze(x[:, 2], 1) * (0.225 / 0.5) + (0.406 - 0.5) / 0.5
x = torch.cat((x_ch0, x_ch1, x_ch2), 1)
return x
def _forward(self, x):
# type: (Tensor) -> Tuple[Tensor, Optional[Tensor], Optional[Tensor]]
# N x 3 x 224 x 224
x = self.conv1(x)
# N x 64 x 112 x 112
x = self.maxpool1(x)
# N x 64 x 56 x 56
x = self.conv2(x)
# N x 64 x 56 x 56
x = self.conv3(x)
# N x 192 x 56 x 56
x = self.maxpool2(x)
# N x 192 x 28 x 28
x = self.inception3a(x)
# N x 256 x 28 x 28
x = self.inception3b(x)
# N x 480 x 28 x 28
x = self.maxpool3(x)
# N x 480 x 14 x 14
x = self.inception4a(x)
# N x 512 x 14 x 14
aux1 = torch.jit.annotate(Optional[Tensor], None)
if self.aux1 is not None:
if self.training:
aux1 = self.aux1(x)
x = self.inception4b(x)
# N x 512 x 14 x 14
x = self.inception4c(x)
# N x 512 x 14 x 14
x = self.inception4d(x)
# N x 528 x 14 x 14
aux2 = torch.jit.annotate(Optional[Tensor], None)
if self.aux2 is not None:
if self.training:
aux2 = self.aux2(x)
x = self.inception4e(x)
# N x 832 x 14 x 14
x = self.maxpool4(x)
# N x 832 x 7 x 7
x = self.inception5a(x)
# N x 832 x 7 x 7
x = self.inception5b(x)
# N x 1024 x 7 x 7
x = self.avgpool(x)
# N x 1024 x 1 x 1
x = torch.flatten(x, 1)
# N x 1024
x = self.dropout(x)
x = self.fc(x)
# N x 1000 (num_classes)
return x, aux2, aux1
@torch.jit.unused
def eager_outputs(self, x, aux2, aux1):
# type: (Tensor, Optional[Tensor], Optional[Tensor]) -> GoogLeNetOutputs
if self.training and self.aux_logits:
return _GoogLeNetOutputs(x, aux2, aux1)
else:
return x
def forward(self, x):
# type: (Tensor) -> GoogLeNetOutputs
x = self._transform_input(x)
x, aux1, aux2 = self._forward(x)
aux_defined = self.training and self.aux_logits
if torch.jit.is_scripting():
if not aux_defined:
warnings.warn("Scripted GoogleNet always returns GoogleNetOutputs Tuple")
return GoogLeNetOutputs(x, aux2, aux1)
else:
return self.eager_outputs(x, aux2, aux1)
class Inception(nn.Module):
def __init__(self, in_channels, ch1x1, ch3x3red, ch3x3, ch5x5red, ch5x5, pool_proj,
conv_block=None):
super(Inception, self).__init__()
if conv_block is None:
conv_block = BasicConv2d
self.branch1 = conv_block(in_channels, ch1x1, kernel_size=1)
self.branch2 = nn.Sequential(
conv_block(in_channels, ch3x3red, kernel_size=1),
conv_block(ch3x3red, ch3x3, kernel_size=3, padding=1)
)
self.branch3 = nn.Sequential(
conv_block(in_channels, ch5x5red, kernel_size=1),
# Here, kernel_size=3 instead of kernel_size=5 is a known bug.
# Please see https://github.com/pytorch/vision/issues/906 for details.
conv_block(ch5x5red, ch5x5, kernel_size=3, padding=1)
)
self.branch4 = nn.Sequential(
nn.MaxPool2d(kernel_size=3, stride=1, padding=1, ceil_mode=True),
conv_block(in_channels, pool_proj, kernel_size=1)
)
def _forward(self, x):
branch1 = self.branch1(x)
branch2 = self.branch2(x)
branch3 = self.branch3(x)
branch4 = self.branch4(x)
outputs = [branch1, branch2, branch3, branch4]
return outputs
def forward(self, x):
outputs = self._forward(x)
return torch.cat(outputs, 1)
class InceptionAux(nn.Module):
def __init__(self, in_channels, num_classes, conv_block=None):
super(InceptionAux, self).__init__()
if conv_block is None:
conv_block = BasicConv2d
self.conv = conv_block(in_channels, 128, kernel_size=1)
self.fc1 = nn.Linear(2048, 1024)
self.fc2 = nn.Linear(1024, num_classes)
def forward(self, x):
# aux1: N x 512 x 14 x 14, aux2: N x 528 x 14 x 14
x = F.adaptive_avg_pool2d(x, (4, 4))
# aux1: N x 512 x 4 x 4, aux2: N x 528 x 4 x 4
x = self.conv(x)
# N x 128 x 4 x 4
x = torch.flatten(x, 1)
# N x 2048
x = F.relu(self.fc1(x), inplace=True)
# N x 1024
x = F.dropout(x, 0.7, training=self.training)
# N x 1024
x = self.fc2(x)
# N x 1000 (num_classes)
return x
class BasicConv2d(nn.Module):
def __init__(self, in_channels, out_channels, **kwargs):
super(BasicConv2d, self).__init__()
self.conv = nn.Conv2d(in_channels, out_channels, bias=False, **kwargs)
self.bn = nn.BatchNorm2d(out_channels, eps=0.001)
def forward(self, x):
x = self.conv(x)
x = self.bn(x)
return F.relu(x, inplace=True)Introduced by Xie et al. in Aggregated Residual Transformations for Deep Neural Networks
A ResNeXt repeats a building block that aggregates a set of transformations with the same topology. Compared to a ResNet, it exposes a new dimension, cardinality (the size of the set of transformations) C, as an essential factor in addition to the dimensions of depth and width.
Source: Aggregated Residual Transformations for Deep Neural Networks
import torch
import torch.nn as nn
from .utils import load_state_dict_from_url
__all__ = ['ResNet', 'resnet18', 'resnet34', 'resnet50', 'resnet101',
'resnet152', 'resnext50_32x4d', 'resnext101_32x8d',
'wide_resnet50_2', 'wide_resnet101_2']
model_urls = {
'resnet18': 'https://download.pytorch.org/models/resnet18-5c106cde.pth',
'resnet34': 'https://download.pytorch.org/models/resnet34-333f7ec4.pth',
'resnet50': 'https://download.pytorch.org/models/resnet50-19c8e357.pth',
'resnet101': 'https://download.pytorch.org/models/resnet101-5d3b4d8f.pth',
'resnet152': 'https://download.pytorch.org/models/resnet152-b121ed2d.pth',
'resnext50_32x4d': 'https://download.pytorch.org/models/resnext50_32x4d-7cdf4587.pth',
'resnext101_32x8d': 'https://download.pytorch.org/models/resnext101_32x8d-8ba56ff5.pth',
'wide_resnet50_2': 'https://download.pytorch.org/models/wide_resnet50_2-95faca4d.pth',
'wide_resnet101_2': 'https://download.pytorch.org/models/wide_resnet101_2-32ee1156.pth',
}
def conv3x3(in_planes, out_planes, stride=1, groups=1, dilation=1):
"""3x3 convolution with padding"""
return nn.Conv2d(in_planes, out_planes, kernel_size=3, stride=stride,
padding=dilation, groups=groups, bias=False, dilation=dilation)
def conv1x1(in_planes, out_planes, stride=1):
"""1x1 convolution"""
return nn.Conv2d(in_planes, out_planes, kernel_size=1, stride=stride, bias=False)
class BasicBlock(nn.Module):
expansion = 1
def __init__(self, inplanes, planes, stride=1, downsample=None, groups=1,
base_width=64, dilation=1, norm_layer=None):
super(BasicBlock, self).__init__()
if norm_layer is None:
norm_layer = nn.BatchNorm2d
if groups != 1 or base_width != 64:
raise ValueError('BasicBlock only supports groups=1 and base_width=64')
if dilation > 1:
raise NotImplementedError("Dilation > 1 not supported in BasicBlock")
# Both self.conv1 and self.downsample layers downsample the input when stride != 1
self.conv1 = conv3x3(inplanes, planes, stride)
self.bn1 = norm_layer(planes)
self.relu = nn.ReLU(inplace=True)
self.conv2 = conv3x3(planes, planes)
self.bn2 = norm_layer(planes)
self.downsample = downsample
self.stride = stride
def forward(self, x):
identity = 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:
identity = self.downsample(x)
out += identity
out = self.relu(out)
return out
class Bottleneck(nn.Module):
# Bottleneck in torchvision places the stride for downsampling at 3x3 convolution(self.conv2)
# while original implementation places the stride at the first 1x1 convolution(self.conv1)
# according to "Deep residual learning for image recognition"https://arxiv.org/abs/1512.03385.
# This variant is also known as ResNet V1.5 and improves accuracy according to
# https://ngc.nvidia.com/catalog/model-scripts/nvidia:resnet_50_v1_5_for_pytorch.
expansion = 4
def __init__(self, inplanes, planes, stride=1, downsample=None, groups=1,
base_width=64, dilation=1, norm_layer=None):
super(Bottleneck, self).__init__()
if norm_layer is None:
norm_layer = nn.BatchNorm2d
width = int(planes * (base_width / 64.)) * groups
# Both self.conv2 and self.downsample layers downsample the input when stride != 1
self.conv1 = conv1x1(inplanes, width)
self.bn1 = norm_layer(width)
self.conv2 = conv3x3(width, width, stride, groups, dilation)
self.bn2 = norm_layer(width)
self.conv3 = conv1x1(width, planes * self.expansion)
self.bn3 = norm_layer(planes * self.expansion)
self.relu = nn.ReLU(inplace=True)
self.downsample = downsample
self.stride = stride
def forward(self, x):
identity = x
out = self.conv1(x)
out = self.bn1(out)
out = self.relu(out)
out = self.conv2(out)
out = self.bn2(out)
out = self.relu(out)
out = self.conv3(out)
out = self.bn3(out)
if self.downsample is not None:
identity = self.downsample(x)
out += identity
out = self.relu(out)
return out
class ResNet(nn.Module):
def __init__(self, block, layers, num_classes=1000, zero_init_residual=False,
groups=1, width_per_group=64, replace_stride_with_dilation=None,
norm_layer=None):
super(ResNet, self).__init__()
if norm_layer is None:
norm_layer = nn.BatchNorm2d
self._norm_layer = norm_layer
self.inplanes = 64
self.dilation = 1
if replace_stride_with_dilation is None:
# each element in the tuple indicates if we should replace
# the 2x2 stride with a dilated convolution instead
replace_stride_with_dilation = [False, False, False]
if len(replace_stride_with_dilation) != 3:
raise ValueError("replace_stride_with_dilation should be None "
"or a 3-element tuple, got {}".format(replace_stride_with_dilation))
self.groups = groups
self.base_width = width_per_group
self.conv1 = nn.Conv2d(3, self.inplanes, kernel_size=7, stride=2, padding=3,
bias=False)
self.bn1 = 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])
self.layer2 = self._make_layer(block, 128, layers[1], stride=2,
dilate=replace_stride_with_dilation[0])
self.layer3 = self._make_layer(block, 256, layers[2], stride=2,
dilate=replace_stride_with_dilation[1])
self.layer4 = self._make_layer(block, 512, layers[3], stride=2,
dilate=replace_stride_with_dilation[2])
self.avgpool = nn.AdaptiveAvgPool2d((1, 1))
self.fc = nn.Linear(512 * block.expansion, num_classes)
for m in self.modules():
if isinstance(m, nn.Conv2d):
nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
elif isinstance(m, (nn.BatchNorm2d, nn.GroupNorm)):
nn.init.constant_(m.weight, 1)
nn.init.constant_(m.bias, 0)
# Zero-initialize the last BN in each residual branch,
# so that the residual branch starts with zeros, and each residual block behaves like an identity.
# This improves the model by 0.2~0.3% according to https://arxiv.org/abs/1706.02677
if zero_init_residual:
for m in self.modules():
if isinstance(m, Bottleneck):
nn.init.constant_(m.bn3.weight, 0)
elif isinstance(m, BasicBlock):
nn.init.constant_(m.bn2.weight, 0)
def _make_layer(self, block, planes, blocks, stride=1, dilate=False):
norm_layer = self._norm_layer
downsample = None
previous_dilation = self.dilation
if dilate:
self.dilation *= stride
stride = 1
if stride != 1 or self.inplanes != planes * block.expansion:
downsample = nn.Sequential(
conv1x1(self.inplanes, planes * block.expansion, stride),
norm_layer(planes * block.expansion),
)
layers = []
layers.append(block(self.inplanes, planes, stride, downsample, self.groups,
self.base_width, previous_dilation, norm_layer))
self.inplanes = planes * block.expansion
for _ in range(1, blocks):
layers.append(block(self.inplanes, planes, groups=self.groups,
base_width=self.base_width, dilation=self.dilation,
norm_layer=norm_layer))
return nn.Sequential(*layers)
def _forward_impl(self, x):
# See note [TorchScript super()]
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)
x = self.avgpool(x)
x = torch.flatten(x, 1)
x = self.fc(x)
return x
def forward(self, x):
return self._forward_impl(x)
def _resnet(arch, block, layers, pretrained, progress, **kwargs):
model = ResNet(block, layers, **kwargs)
if pretrained:
state_dict = load_state_dict_from_url(model_urls[arch],
progress=progress)
model.load_state_dict(state_dict)
return model
def resnet18(pretrained=False, progress=True, **kwargs):
r"""ResNet-18 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet18', BasicBlock, [2, 2, 2, 2], pretrained, progress,
**kwargs)
def resnet34(pretrained=False, progress=True, **kwargs):
r"""ResNet-34 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet34', BasicBlock, [3, 4, 6, 3], pretrained, progress,
**kwargs)
def resnet50(pretrained=False, progress=True, **kwargs):
r"""ResNet-50 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet50', Bottleneck, [3, 4, 6, 3], pretrained, progress,
**kwargs)
def resnet101(pretrained=False, progress=True, **kwargs):
r"""ResNet-101 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet101', Bottleneck, [3, 4, 23, 3], pretrained, progress,
**kwargs)
def resnet152(pretrained=False, progress=True, **kwargs):
r"""ResNet-152 model from
`"Deep Residual Learning for Image Recognition" <https://arxiv.org/pdf/1512.03385.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _resnet('resnet152', Bottleneck, [3, 8, 36, 3], pretrained, progress,
**kwargs)
def resnext50_32x4d(pretrained=False, progress=True, **kwargs):
r"""ResNeXt-50 32x4d model from
`"Aggregated Residual Transformation for Deep Neural Networks" <https://arxiv.org/pdf/1611.05431.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
kwargs['groups'] = 32
kwargs['width_per_group'] = 4
return _resnet('resnext50_32x4d', Bottleneck, [3, 4, 6, 3],
pretrained, progress, **kwargs)
def resnext101_32x8d(pretrained=False, progress=True, **kwargs):
r"""ResNeXt-101 32x8d model from
`"Aggregated Residual Transformation for Deep Neural Networks" <https://arxiv.org/pdf/1611.05431.pdf>`_
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
kwargs['groups'] = 32
kwargs['width_per_group'] = 8
return _resnet('resnext101_32x8d', Bottleneck, [3, 4, 23, 3],
pretrained, progress, **kwargs)
def wide_resnet50_2(pretrained=False, progress=True, **kwargs):
r"""Wide ResNet-50-2 model from
`"Wide Residual Networks" <https://arxiv.org/pdf/1605.07146.pdf>`_
The model is the same as ResNet except for the bottleneck number of channels
which is twice larger in every block. The number of channels in outer 1x1
convolutions is the same, e.g. last block in ResNet-50 has 2048-512-2048
channels, and in Wide ResNet-50-2 has 2048-1024-2048.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
kwargs['width_per_group'] = 64 * 2
return _resnet('wide_resnet50_2', Bottleneck, [3, 4, 6, 3],
pretrained, progress, **kwargs)
def wide_resnet101_2(pretrained=False, progress=True, **kwargs):
r"""Wide ResNet-101-2 model from
`"Wide Residual Networks" <https://arxiv.org/pdf/1605.07146.pdf>`_
The model is the same as ResNet except for the bottleneck number of channels
which is twice larger in every block. The number of channels in outer 1x1
convolutions is the same, e.g. last block in ResNet-50 has 2048-512-2048
channels, and in Wide ResNet-50-2 has 2048-1024-2048.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
kwargs['width_per_group'] = 64 * 2
return _resnet('wide_resnet101_2', Bottleneck, [3, 4, 23, 3],
pretrained, progress, **kwargs)Introduced by Redmon et al. in YOLOv3: An Incremental Improvement
Darknet-53 is a convolutional neural network that acts as a backbone for the YOLOv3 object detection approach. The improvements upon its predecessor Darknet-19 include the use of residual connections, as well as more layers.
Source: YOLOv3: An Incremental Improvement
from utils.google_utils import *
from utils.layers import *
from utils.parse_config import *
ONNX_EXPORT = False
def create_modules(module_defs, img_size, cfg):
# Constructs module list of layer blocks from module configuration in module_defs
img_size = [img_size] * 2 if isinstance(img_size, int) else img_size # expand if necessary
_ = module_defs.pop(0) # cfg training hyperparams (unused)
output_filters = [3] # input channels
module_list = nn.ModuleList()
routs = [] # list of layers which rout to deeper layers
yolo_index = -1
for i, mdef in enumerate(module_defs):
modules = nn.Sequential()
if mdef['type'] == 'convolutional':
bn = mdef['batch_normalize']
filters = mdef['filters']
k = mdef['size'] # kernel size
stride = mdef['stride'] if 'stride' in mdef else (mdef['stride_y'], mdef['stride_x'])
if isinstance(k, int): # single-size conv
modules.add_module('Conv2d', nn.Conv2d(in_channels=output_filters[-1],
out_channels=filters,
kernel_size=k,
stride=stride,
padding=k // 2 if mdef['pad'] else 0,
groups=mdef['groups'] if 'groups' in mdef else 1,
bias=not bn))
else: # multiple-size conv
modules.add_module('MixConv2d', MixConv2d(in_ch=output_filters[-1],
out_ch=filters,
k=k,
stride=stride,
bias=not bn))
if bn:
modules.add_module('BatchNorm2d', nn.BatchNorm2d(filters, momentum=0.03, eps=1E-4))
else:
routs.append(i) # detection output (goes into yolo layer)
if mdef['activation'] == 'leaky': # activation study https://github.com/ultralytics/yolov3/issues/441
modules.add_module('activation', nn.LeakyReLU(0.1, inplace=True))
elif mdef['activation'] == 'swish':
modules.add_module('activation', Swish())
elif mdef['activation'] == 'mish':
modules.add_module('activation', Mish())
elif mdef['type'] == 'BatchNorm2d':
filters = output_filters[-1]
modules = nn.BatchNorm2d(filters, momentum=0.03, eps=1E-4)
if i == 0 and filters == 3: # normalize RGB image
# imagenet mean and var https://pytorch.org/docs/stable/torchvision/models.html#classification
modules.running_mean = torch.tensor([0.485, 0.456, 0.406])
modules.running_var = torch.tensor([0.0524, 0.0502, 0.0506])
elif mdef['type'] == 'maxpool':
k = mdef['size'] # kernel size
stride = mdef['stride']
maxpool = nn.MaxPool2d(kernel_size=k, stride=stride, padding=(k - 1) // 2)
if k == 2 and stride == 1: # yolov3-tiny
modules.add_module('ZeroPad2d', nn.ZeroPad2d((0, 1, 0, 1)))
modules.add_module('MaxPool2d', maxpool)
else:
modules = maxpool
elif mdef['type'] == 'upsample':
if ONNX_EXPORT: # explicitly state size, avoid scale_factor
g = (yolo_index + 1) * 2 / 32 # gain
modules = nn.Upsample(size=tuple(int(x * g) for x in img_size)) # img_size = (320, 192)
else:
modules = nn.Upsample(scale_factor=mdef['stride'])
elif mdef['type'] == 'route': # nn.Sequential() placeholder for 'route' layer
layers = mdef['layers']
filters = sum([output_filters[l + 1 if l > 0 else l] for l in layers])
routs.extend([i + l if l < 0 else l for l in layers])
modules = FeatureConcat(layers=layers)
elif mdef['type'] == 'shortcut': # nn.Sequential() placeholder for 'shortcut' layer
layers = mdef['from']
filters = output_filters[-1]
routs.extend([i + l if l < 0 else l for l in layers])
modules = WeightedFeatureFusion(layers=layers, weight='weights_type' in mdef)
elif mdef['type'] == 'reorg3d': # yolov3-spp-pan-scale
pass
elif mdef['type'] == 'yolo':
yolo_index += 1
stride = [32, 16, 8] # P5, P4, P3 strides
if any(x in cfg for x in ['panet', 'yolov4', 'cd53']): # stride order reversed
stride = list(reversed(stride))
layers = mdef['from'] if 'from' in mdef else []
modules = YOLOLayer(anchors=mdef['anchors'][mdef['mask']], # anchor list
nc=mdef['classes'], # number of classes
img_size=img_size, # (416, 416)
yolo_index=yolo_index, # 0, 1, 2...
layers=layers, # output layers
stride=stride[yolo_index])
# Initialize preceding Conv2d() bias (https://arxiv.org/pdf/1708.02002.pdf section 3.3)
try:
j = layers[yolo_index] if 'from' in mdef else -1
# If previous layer is a dropout layer, get the one before
if module_list[j].__class__.__name__ == 'Dropout':
j -= 1
bias_ = module_list[j][0].bias # shape(255,)
bias = bias_[:modules.no * modules.na].view(modules.na, -1) # shape(3,85)
bias[:, 4] += -4.5 # obj
bias[:, 5:] += math.log(0.6 / (modules.nc - 0.99)) # cls (sigmoid(p) = 1/nc)
module_list[j][0].bias = torch.nn.Parameter(bias_, requires_grad=bias_.requires_grad)
except:
print('WARNING: smart bias initialization failure.')
elif mdef['type'] == 'dropout':
perc = float(mdef['probability'])
modules = nn.Dropout(p=perc)
else:
print('Warning: Unrecognized Layer Type: ' + mdef['type'])
# Register module list and number of output filters
module_list.append(modules)
output_filters.append(filters)
routs_binary = [False] * (i + 1)
for i in routs:
routs_binary[i] = True
return module_list, routs_binary
class YOLOLayer(nn.Module):
def __init__(self, anchors, nc, img_size, yolo_index, layers, stride):
super(YOLOLayer, self).__init__()
self.anchors = torch.Tensor(anchors)
self.index = yolo_index # index of this layer in layers
self.layers = layers # model output layer indices
self.stride = stride # layer stride
self.nl = len(layers) # number of output layers (3)
self.na = len(anchors) # number of anchors (3)
self.nc = nc # number of classes (80)
self.no = nc + 5 # number of outputs (85)
self.nx, self.ny, self.ng = 0, 0, 0 # initialize number of x, y gridpoints
self.anchor_vec = self.anchors / self.stride
self.anchor_wh = self.anchor_vec.view(1, self.na, 1, 1, 2)
if ONNX_EXPORT:
self.training = False
self.create_grids((img_size[1] // stride, img_size[0] // stride)) # number x, y grid points
def create_grids(self, ng=(13, 13), device='cpu'):
self.nx, self.ny = ng # x and y grid size
self.ng = torch.tensor(ng, dtype=torch.float)
# build xy offsets
if not self.training:
yv, xv = torch.meshgrid([torch.arange(self.ny, device=device), torch.arange(self.nx, device=device)])
self.grid = torch.stack((xv, yv), 2).view((1, 1, self.ny, self.nx, 2)).float()
if self.anchor_vec.device != device:
self.anchor_vec = self.anchor_vec.to(device)
self.anchor_wh = self.anchor_wh.to(device)
def forward(self, p, out):
ASFF = False # https://arxiv.org/abs/1911.09516
if ASFF:
i, n = self.index, self.nl # index in layers, number of layers
p = out[self.layers[i]]
bs, _, ny, nx = p.shape # bs, 255, 13, 13
if (self.nx, self.ny) != (nx, ny):
self.create_grids((nx, ny), p.device)
# outputs and weights
# w = F.softmax(p[:, -n:], 1) # normalized weights
w = torch.sigmoid(p[:, -n:]) * (2 / n) # sigmoid weights (faster)
# w = w / w.sum(1).unsqueeze(1) # normalize across layer dimension
# weighted ASFF sum
p = out[self.layers[i]][:, :-n] * w[:, i:i + 1]
for j in range(n):
if j != i:
p += w[:, j:j + 1] * \
F.interpolate(out[self.layers[j]][:, :-n], size=[ny, nx], mode='bilinear', align_corners=False)
elif ONNX_EXPORT:
bs = 1 # batch size
else:
bs, _, ny, nx = p.shape # bs, 255, 13, 13
if (self.nx, self.ny) != (nx, ny):
self.create_grids((nx, ny), p.device)
# p.view(bs, 255, 13, 13) -- > (bs, 3, 13, 13, 85) # (bs, anchors, grid, grid, classes + xywh)
p = p.view(bs, self.na, self.no, self.ny, self.nx).permute(0, 1, 3, 4, 2).contiguous() # prediction
if self.training:
return p
elif ONNX_EXPORT:
# Avoid broadcasting for ANE operations
m = self.na * self.nx * self.ny
ng = 1. / self.ng.repeat(m, 1)
grid = self.grid.repeat(1, self.na, 1, 1, 1).view(m, 2)
anchor_wh = self.anchor_wh.repeat(1, 1, self.nx, self.ny, 1).view(m, 2) * ng
p = p.view(m, self.no)
xy = torch.sigmoid(p[:, 0:2]) + grid # x, y
wh = torch.exp(p[:, 2:4]) * anchor_wh # width, height
p_cls = torch.sigmoid(p[:, 4:5]) if self.nc == 1 else \
torch.sigmoid(p[:, 5:self.no]) * torch.sigmoid(p[:, 4:5]) # conf
return p_cls, xy * ng, wh
else: # inference
io = p.clone() # inference output
io[..., :2] = torch.sigmoid(io[..., :2]) + self.grid # xy
io[..., 2:4] = torch.exp(io[..., 2:4]) * self.anchor_wh # wh yolo method
io[..., :4] *= self.stride
torch.sigmoid_(io[..., 4:])
return io.view(bs, -1, self.no), p # view [1, 3, 13, 13, 85] as [1, 507, 85]
class Darknet(nn.Module):
# YOLOv3 object detection model
def __init__(self, cfg, img_size=(416, 416), verbose=False):
super(Darknet, self).__init__()
self.module_defs = parse_model_cfg(cfg)
self.module_list, self.routs = create_modules(self.module_defs, img_size, cfg)
self.yolo_layers = get_yolo_layers(self)
# torch_utils.initialize_weights(self)
# Darknet Header https://github.com/AlexeyAB/darknet/issues/2914#issuecomment-496675346
self.version = np.array([0, 2, 5], dtype=np.int32) # (int32) version info: major, minor, revision
self.seen = np.array([0], dtype=np.int64) # (int64) number of images seen during training
self.info(verbose) if not ONNX_EXPORT else None # print model description
def forward(self, x, augment=False, verbose=False):
if not augment:
return self.forward_once(x)
else: # Augment images (inference and test only) https://github.com/ultralytics/yolov3/issues/931
img_size = x.shape[-2:] # height, width
s = [0.83, 0.67] # scales
y = []
for i, xi in enumerate((x,
torch_utils.scale_img(x.flip(3), s[0], same_shape=False), # flip-lr and scale
torch_utils.scale_img(x, s[1], same_shape=False), # scale
)):
# cv2.imwrite('img%g.jpg' % i, 255 * xi[0].numpy().transpose((1, 2, 0))[:, :, ::-1])
y.append(self.forward_once(xi)[0])
y[1][..., :4] /= s[0] # scale
y[1][..., 0] = img_size[1] - y[1][..., 0] # flip lr
y[2][..., :4] /= s[1] # scale
# for i, yi in enumerate(y): # coco small, medium, large = < 32**2 < 96**2 <
# area = yi[..., 2:4].prod(2)[:, :, None]
# if i == 1:
# yi *= (area < 96. ** 2).float()
# elif i == 2:
# yi *= (area > 32. ** 2).float()
# y[i] = yi
y = torch.cat(y, 1)
return y, None
def forward_once(self, x, augment=False, verbose=False):
img_size = x.shape[-2:] # height, width
yolo_out, out = [], []
if verbose:
print('0', x.shape)
str = ''
# Augment images (inference and test only)
if augment: # https://github.com/ultralytics/yolov3/issues/931
nb = x.shape[0] # batch size
s = [0.83, 0.67] # scales
x = torch.cat((x,
torch_utils.scale_img(x.flip(3), s[0]), # flip-lr and scale
torch_utils.scale_img(x, s[1]), # scale
), 0)
for i, module in enumerate(self.module_list):
name = module.__class__.__name__
if name in ['WeightedFeatureFusion', 'FeatureConcat']: # sum, concat
if verbose:
l = [i - 1] + module.layers # layers
sh = [list(x.shape)] + [list(out[i].shape) for i in module.layers] # shapes
str = ' >> ' + ' + '.join(['layer %g %s' % x for x in zip(l, sh)])
x = module(x, out) # WeightedFeatureFusion(), FeatureConcat()
elif name == 'YOLOLayer':
yolo_out.append(module(x, out))
else: # run module directly, i.e. mtype = 'convolutional', 'upsample', 'maxpool', 'batchnorm2d' etc.
x = module(x)
out.append(x if self.routs[i] else [])
if verbose:
print('%g/%g %s -' % (i, len(self.module_list), name), list(x.shape), str)
str = ''
if self.training: # train
return yolo_out
elif ONNX_EXPORT: # export
x = [torch.cat(x, 0) for x in zip(*yolo_out)]
return x[0], torch.cat(x[1:3], 1) # scores, boxes: 3780x80, 3780x4
else: # inference or test
x, p = zip(*yolo_out) # inference output, training output
x = torch.cat(x, 1) # cat yolo outputs
if augment: # de-augment results
x = torch.split(x, nb, dim=0)
x[1][..., :4] /= s[0] # scale
x[1][..., 0] = img_size[1] - x[1][..., 0] # flip lr
x[2][..., :4] /= s[1] # scale
x = torch.cat(x, 1)
return x, p
def fuse(self):
# Fuse Conv2d + BatchNorm2d layers throughout model
print('Fusing layers...')
fused_list = nn.ModuleList()
for a in list(self.children())[0]:
if isinstance(a, nn.Sequential):
for i, b in enumerate(a):
if isinstance(b, nn.modules.batchnorm.BatchNorm2d):
# fuse this bn layer with the previous conv2d layer
conv = a[i - 1]
fused = torch_utils.fuse_conv_and_bn(conv, b)
a = nn.Sequential(fused, *list(a.children())[i + 1:])
break
fused_list.append(a)
self.module_list = fused_list
self.info() if not ONNX_EXPORT else None # yolov3-spp reduced from 225 to 152 layers
def info(self, verbose=False):
torch_utils.model_info(self, verbose)
def get_yolo_layers(model):
return [i for i, m in enumerate(model.module_list) if m.__class__.__name__ == 'YOLOLayer'] # [89, 101, 113]
def load_darknet_weights(self, weights, cutoff=-1):
# Parses and loads the weights stored in 'weights'
# Establish cutoffs (load layers between 0 and cutoff. if cutoff = -1 all are loaded)
file = Path(weights).name
if file == 'darknet53.conv.74':
cutoff = 75
elif file == 'yolov3-tiny.conv.15':
cutoff = 15
# Read weights file
with open(weights, 'rb') as f:
# Read Header https://github.com/AlexeyAB/darknet/issues/2914#issuecomment-496675346
self.version = np.fromfile(f, dtype=np.int32, count=3) # (int32) version info: major, minor, revision
self.seen = np.fromfile(f, dtype=np.int64, count=1) # (int64) number of images seen during training
weights = np.fromfile(f, dtype=np.float32) # the rest are weights
ptr = 0
for i, (mdef, module) in enumerate(zip(self.module_defs[:cutoff], self.module_list[:cutoff])):
if mdef['type'] == 'convolutional':
conv = module[0]
if mdef['batch_normalize']:
# Load BN bias, weights, running mean and running variance
bn = module[1]
nb = bn.bias.numel() # number of biases
# Bias
bn.bias.data.copy_(torch.from_numpy(weights[ptr:ptr + nb]).view_as(bn.bias))
ptr += nb
# Weight
bn.weight.data.copy_(torch.from_numpy(weights[ptr:ptr + nb]).view_as(bn.weight))
ptr += nb
# Running Mean
bn.running_mean.data.copy_(torch.from_numpy(weights[ptr:ptr + nb]).view_as(bn.running_mean))
ptr += nb
# Running Var
bn.running_var.data.copy_(torch.from_numpy(weights[ptr:ptr + nb]).view_as(bn.running_var))
ptr += nb
else:
# Load conv. bias
nb = conv.bias.numel()
conv_b = torch.from_numpy(weights[ptr:ptr + nb]).view_as(conv.bias)
conv.bias.data.copy_(conv_b)
ptr += nb
# Load conv. weights
nw = conv.weight.numel() # number of weights
conv.weight.data.copy_(torch.from_numpy(weights[ptr:ptr + nw]).view_as(conv.weight))
ptr += nw
def save_weights(self, path='model.weights', cutoff=-1):
# Converts a PyTorch model to Darket format (*.pt to *.weights)
# Note: Does not work if model.fuse() is applied
with open(path, 'wb') as f:
# Write Header https://github.com/AlexeyAB/darknet/issues/2914#issuecomment-496675346
self.version.tofile(f) # (int32) version info: major, minor, revision
self.seen.tofile(f) # (int64) number of images seen during training
# Iterate through layers
for i, (mdef, module) in enumerate(zip(self.module_defs[:cutoff], self.module_list[:cutoff])):
if mdef['type'] == 'convolutional':
conv_layer = module[0]
# If batch norm, load bn first
if mdef['batch_normalize']:
bn_layer = module[1]
bn_layer.bias.data.cpu().numpy().tofile(f)
bn_layer.weight.data.cpu().numpy().tofile(f)
bn_layer.running_mean.data.cpu().numpy().tofile(f)
bn_layer.running_var.data.cpu().numpy().tofile(f)
# Load conv bias
else:
conv_layer.bias.data.cpu().numpy().tofile(f)
# Load conv weights
conv_layer.weight.data.cpu().numpy().tofile(f)
def convert(cfg='cfg/yolov3-spp.cfg', weights='weights/yolov3-spp.weights'):
# Converts between PyTorch and Darknet format per extension (i.e. *.weights convert to *.pt and vice versa)
# from models import *; convert('cfg/yolov3-spp.cfg', 'weights/yolov3-spp.weights')
# Initialize model
model = Darknet(cfg)
# Load weights and save
if weights.endswith('.pt'): # if PyTorch format
model.load_state_dict(torch.load(weights, map_location='cpu')['model'])
target = weights.rsplit('.', 1)[0] + '.weights'
save_weights(model, path=target, cutoff=-1)
print("Success: converted '%s' to '%s'" % (weights, target))
elif weights.endswith('.weights'): # darknet format
_ = load_darknet_weights(model, weights)
chkpt = {'epoch': -1,
'best_fitness': None,
'training_results': None,
'model': model.state_dict(),
'optimizer': None}
target = weights.rsplit('.', 1)[0] + '.pt'
torch.save(chkpt, target)
print("Success: converted '%s' to '%s'" % (weights, target))
else:
print('Error: extension not supported.')
def attempt_download(weights):
# Attempt to download pretrained weights if not found locally
weights = weights.strip().replace("'", '')
msg = weights + ' missing, try downloading from https://drive.google.com/open?id=1LezFG5g3BCW6iYaV89B2i64cqEUZD7e0'
if len(weights) > 0 and not os.path.isfile(weights):
d = {'yolov3-spp.weights': '16lYS4bcIdM2HdmyJBVDOvt3Trx6N3W2R',
'yolov3.weights': '1uTlyDWlnaqXcsKOktP5aH_zRDbfcDp-y',
'yolov3-tiny.weights': '1CCF-iNIIkYesIDzaPvdwlcf7H9zSsKZQ',
'yolov3-spp.pt': '1f6Ovy3BSq2wYq4UfvFUpxJFNDFfrIDcR',
'yolov3.pt': '1SHNFyoe5Ni8DajDNEqgB2oVKBb_NoEad',
'yolov3-tiny.pt': '10m_3MlpQwRtZetQxtksm9jqHrPTHZ6vo',
'darknet53.conv.74': '1WUVBid-XuoUBmvzBVUCBl_ELrzqwA8dJ',
'yolov3-tiny.conv.15': '1Bw0kCpplxUqyRYAJr9RY9SGnOJbo9nEj',
'yolov3-spp-ultralytics.pt': '1UcR-zVoMs7DH5dj3N1bswkiQTA4dmKF4'}
file = Path(weights).name
if file in d:
r = gdrive_download(id=d[file], name=weights)
else: # download from pjreddie.com
url = 'https://pjreddie.com/media/files/' + file
print('Downloading ' + url)
r = os.system('curl -f ' + url + ' -o ' + weights)
# Error check
if not (r == 0 and os.path.exists(weights) and os.path.getsize(weights) > 1E6): # weights exist and > 1MB
os.system('rm ' + weights) # remove partial downloads
raise Exception(msg)Introduced by Tan et al. in EfficientNet: Rethinking Model Scaling for Convolutional Neural Networks
EfficientNet is a convolutional neural network architecture and scaling method that uniformly scales all dimensions of depth/width/resolution using a compound coefficient. Unlike conventional practice that arbitrary scales these factors, the EfficientNet scaling method uniformly scales network width, depth, and resolution with a set of fixed scaling coefficients. For example, if we want to use times more computational resources, then we can simply increase the network depth by , width by , and image size by , where are constant coefficients determined by a small grid search on the original small model. EfficientNet uses a compound coefficient to uniformly scales network width, depth, and resolution in a principled way.
The compound scaling method is justified by the intuition that if the input image is bigger, then the network needs more layers to increase the receptive field and more channels to capture more fine-grained patterns on the bigger image.
The base EfficientNet-B0 network is based on the inverted bottleneck residual blocks of MobileNetV2, in addition to squeeze-and-excitation blocks.
Source: EfficientNet: Rethinking Model Scaling for Convolutional Neural Networks
"""model.py - Model and module class for EfficientNet.
They are built to mirror those in the official TensorFlow implementation.
"""
# Author: lukemelas (github username)
# Github repo: https://github.com/lukemelas/EfficientNet-PyTorch
# With adjustments and added comments by workingcoder (github username).
import torch
from torch import nn
from torch.nn import functional as F
from .utils import (
round_filters,
round_repeats,
drop_connect,
get_same_padding_conv2d,
get_model_params,
efficientnet_params,
load_pretrained_weights,
Swish,
MemoryEfficientSwish,
calculate_output_image_size
)
VALID_MODELS = (
'efficientnet-b0', 'efficientnet-b1', 'efficientnet-b2', 'efficientnet-b3',
'efficientnet-b4', 'efficientnet-b5', 'efficientnet-b6', 'efficientnet-b7',
'efficientnet-b8',
# Support the construction of 'efficientnet-l2' without pretrained weights
'efficientnet-l2'
)
class MBConvBlock(nn.Module):
"""Mobile Inverted Residual Bottleneck Block.
Args:
block_args (namedtuple): BlockArgs, defined in utils.py.
global_params (namedtuple): GlobalParam, defined in utils.py.
image_size (tuple or list): [image_height, image_width].
References:
[1] https://arxiv.org/abs/1704.04861 (MobileNet v1)
[2] https://arxiv.org/abs/1801.04381 (MobileNet v2)
[3] https://arxiv.org/abs/1905.02244 (MobileNet v3)
"""
def __init__(self, block_args, global_params, image_size=None):
super().__init__()
self._block_args = block_args
self._bn_mom = 1 - global_params.batch_norm_momentum # pytorch's difference from tensorflow
self._bn_eps = global_params.batch_norm_epsilon
self.has_se = (self._block_args.se_ratio is not None) and (0 < self._block_args.se_ratio <= 1)
self.id_skip = block_args.id_skip # whether to use skip connection and drop connect
# Expansion phase (Inverted Bottleneck)
inp = self._block_args.input_filters # number of input channels
oup = self._block_args.input_filters * self._block_args.expand_ratio # number of output channels
if self._block_args.expand_ratio != 1:
Conv2d = get_same_padding_conv2d(image_size=image_size)
self._expand_conv = Conv2d(in_channels=inp, out_channels=oup, kernel_size=1, bias=False)
self._bn0 = nn.BatchNorm2d(num_features=oup, momentum=self._bn_mom, eps=self._bn_eps)
# image_size = calculate_output_image_size(image_size, 1) <-- this wouldn't modify image_size
# Depthwise convolution phase
k = self._block_args.kernel_size
s = self._block_args.stride
Conv2d = get_same_padding_conv2d(image_size=image_size)
self._depthwise_conv = Conv2d(
in_channels=oup, out_channels=oup, groups=oup, # groups makes it depthwise
kernel_size=k, stride=s, bias=False)
self._bn1 = nn.BatchNorm2d(num_features=oup, momentum=self._bn_mom, eps=self._bn_eps)
image_size = calculate_output_image_size(image_size, s)
# Squeeze and Excitation layer, if desired
if self.has_se:
Conv2d = get_same_padding_conv2d(image_size=(1,1))
num_squeezed_channels = max(1, int(self._block_args.input_filters * self._block_args.se_ratio))
self._se_reduce = Conv2d(in_channels=oup, out_channels=num_squeezed_channels, kernel_size=1)
self._se_expand = Conv2d(in_channels=num_squeezed_channels, out_channels=oup, kernel_size=1)
# Pointwise convolution phase
final_oup = self._block_args.output_filters
Conv2d = get_same_padding_conv2d(image_size=image_size)
self._project_conv = Conv2d(in_channels=oup, out_channels=final_oup, kernel_size=1, bias=False)
self._bn2 = nn.BatchNorm2d(num_features=final_oup, momentum=self._bn_mom, eps=self._bn_eps)
self._swish = MemoryEfficientSwish()
def forward(self, inputs, drop_connect_rate=None):
"""MBConvBlock's forward function.
Args:
inputs (tensor): Input tensor.
drop_connect_rate (bool): Drop connect rate (float, between 0 and 1).
Returns:
Output of this block after processing.
"""
# Expansion and Depthwise Convolution
x = inputs
if self._block_args.expand_ratio != 1:
x = self._expand_conv(inputs)
x = self._bn0(x)
x = self._swish(x)
x = self._depthwise_conv(x)
x = self._bn1(x)
x = self._swish(x)
# Squeeze and Excitation
if self.has_se:
x_squeezed = F.adaptive_avg_pool2d(x, 1)
x_squeezed = self._se_reduce(x_squeezed)
x_squeezed = self._swish(x_squeezed)
x_squeezed = self._se_expand(x_squeezed)
x = torch.sigmoid(x_squeezed) * x
# Pointwise Convolution
x = self._project_conv(x)
x = self._bn2(x)
# Skip connection and drop connect
input_filters, output_filters = self._block_args.input_filters, self._block_args.output_filters
if self.id_skip and self._block_args.stride == 1 and input_filters == output_filters:
# The combination of skip connection and drop connect brings about stochastic depth.
if drop_connect_rate:
x = drop_connect(x, p=drop_connect_rate, training=self.training)
x = x + inputs # skip connection
return x
def set_swish(self, memory_efficient=True):
"""Sets swish function as memory efficient (for training) or standard (for export).
Args:
memory_efficient (bool): Whether to use memory-efficient version of swish.
"""
self._swish = MemoryEfficientSwish() if memory_efficient else Swish()
class EfficientNet(nn.Module):
"""EfficientNet model.
Most easily loaded with the .from_name or .from_pretrained methods.
Args:
blocks_args (list[namedtuple]): A list of BlockArgs to construct blocks.
global_params (namedtuple): A set of GlobalParams shared between blocks.
References:
[1] https://arxiv.org/abs/1905.11946 (EfficientNet)
Example:
>>> import torch
>>> from efficientnet.model import EfficientNet
>>> inputs = torch.rand(1, 3, 224, 224)
>>> model = EfficientNet.from_pretrained('efficientnet-b0')
>>> model.eval()
>>> outputs = model(inputs)
"""
def __init__(self, blocks_args=None, global_params=None):
super().__init__()
assert isinstance(blocks_args, list), 'blocks_args should be a list'
assert len(blocks_args) > 0, 'block args must be greater than 0'
self._global_params = global_params
self._blocks_args = blocks_args
# Batch norm parameters
bn_mom = 1 - self._global_params.batch_norm_momentum
bn_eps = self._global_params.batch_norm_epsilon
# Get stem static or dynamic convolution depending on image size
image_size = global_params.image_size
Conv2d = get_same_padding_conv2d(image_size=image_size)
# Stem
in_channels = 3 # rgb
out_channels = round_filters(32, self._global_params) # number of output channels
self._conv_stem = Conv2d(in_channels, out_channels, kernel_size=3, stride=2, bias=False)
self._bn0 = nn.BatchNorm2d(num_features=out_channels, momentum=bn_mom, eps=bn_eps)
image_size = calculate_output_image_size(image_size, 2)
# Build blocks
self._blocks = nn.ModuleList([])
for block_args in self._blocks_args:
# Update block input and output filters based on depth multiplier.
block_args = block_args._replace(
input_filters=round_filters(block_args.input_filters, self._global_params),
output_filters=round_filters(block_args.output_filters, self._global_params),
num_repeat=round_repeats(block_args.num_repeat, self._global_params)
)
# The first block needs to take care of stride and filter size increase.
self._blocks.append(MBConvBlock(block_args, self._global_params, image_size=image_size))
image_size = calculate_output_image_size(image_size, block_args.stride)
if block_args.num_repeat > 1: # modify block_args to keep same output size
block_args = block_args._replace(input_filters=block_args.output_filters, stride=1)
for _ in range(block_args.num_repeat - 1):
self._blocks.append(MBConvBlock(block_args, self._global_params, image_size=image_size))
# image_size = calculate_output_image_size(image_size, block_args.stride) # stride = 1
# Head
in_channels = block_args.output_filters # output of final block
out_channels = round_filters(1280, self._global_params)
Conv2d = get_same_padding_conv2d(image_size=image_size)
self._conv_head = Conv2d(in_channels, out_channels, kernel_size=1, bias=False)
self._bn1 = nn.BatchNorm2d(num_features=out_channels, momentum=bn_mom, eps=bn_eps)
# Final linear layer
self._avg_pooling = nn.AdaptiveAvgPool2d(1)
self._dropout = nn.Dropout(self._global_params.dropout_rate)
self._fc = nn.Linear(out_channels, self._global_params.num_classes)
self._swish = MemoryEfficientSwish()
def set_swish(self, memory_efficient=True):
"""Sets swish function as memory efficient (for training) or standard (for export).
Args:
memory_efficient (bool): Whether to use memory-efficient version of swish.
"""
self._swish = MemoryEfficientSwish() if memory_efficient else Swish()
for block in self._blocks:
block.set_swish(memory_efficient)
def extract_endpoints(self, inputs):
"""Use convolution layer to extract features
from reduction levels i in [1, 2, 3, 4, 5].
Args:
inputs (tensor): Input tensor.
Returns:
Dictionary of last intermediate features
with reduction levels i in [1, 2, 3, 4, 5].
Example:
>>> import torch
>>> from efficientnet.model import EfficientNet
>>> inputs = torch.rand(1, 3, 224, 224)
>>> model = EfficientNet.from_pretrained('efficientnet-b0')
>>> endpoints = model.extract_endpoints(inputs)
>>> print(endpoints['reduction_1'].shape) # torch.Size([1, 16, 112, 112])
>>> print(endpoints['reduction_2'].shape) # torch.Size([1, 24, 56, 56])
>>> print(endpoints['reduction_3'].shape) # torch.Size([1, 40, 28, 28])
>>> print(endpoints['reduction_4'].shape) # torch.Size([1, 112, 14, 14])
>>> print(endpoints['reduction_5'].shape) # torch.Size([1, 1280, 7, 7])
"""
endpoints = dict()
# Stem
x = self._swish(self._bn0(self._conv_stem(inputs)))
prev_x = x
# Blocks
for idx, block in enumerate(self._blocks):
drop_connect_rate = self._global_params.drop_connect_rate
if drop_connect_rate:
drop_connect_rate *= float(idx) / len(self._blocks) # scale drop connect_rate
x = block(x, drop_connect_rate=drop_connect_rate)
if prev_x.size(2) > x.size(2):
endpoints[f'reduction_{len(endpoints)+1}'] = prev_x
prev_x = x
# Head
x = self._swish(self._bn1(self._conv_head(x)))
endpoints[f'reduction_{len(endpoints)+1}'] = x
return endpoints
def extract_features(self, inputs):
"""use convolution layer to extract feature .
Args:
inputs (tensor): Input tensor.
Returns:
Output of the final convolution
layer in the efficientnet model.
"""
# Stem
x = self._swish(self._bn0(self._conv_stem(inputs)))
# Blocks
for idx, block in enumerate(self._blocks):
drop_connect_rate = self._global_params.drop_connect_rate
if drop_connect_rate:
drop_connect_rate *= float(idx) / len(self._blocks) # scale drop connect_rate
x = block(x, drop_connect_rate=drop_connect_rate)
# Head
x = self._swish(self._bn1(self._conv_head(x)))
return x
def forward(self, inputs):
"""EfficientNet's forward function.
Calls extract_features to extract features, applies final linear layer, and returns logits.
Args:
inputs (tensor): Input tensor.
Returns:
Output of this model after processing.
"""
# Convolution layers
x = self.extract_features(inputs)
# Pooling and final linear layer
x = self._avg_pooling(x)
x = x.flatten(start_dim=1)
x = self._dropout(x)
x = self._fc(x)
return x
@classmethod
def from_name(cls, model_name, in_channels=3, **override_params):
"""create an efficientnet model according to name.
Args:
model_name (str): Name for efficientnet.
in_channels (int): Input data's channel number.
override_params (other key word params):
Params to override model's global_params.
Optional key:
'width_coefficient', 'depth_coefficient',
'image_size', 'dropout_rate',
'num_classes', 'batch_norm_momentum',
'batch_norm_epsilon', 'drop_connect_rate',
'depth_divisor', 'min_depth'
Returns:
An efficientnet model.
"""
cls._check_model_name_is_valid(model_name)
blocks_args, global_params = get_model_params(model_name, override_params)
model = cls(blocks_args, global_params)
model._change_in_channels(in_channels)
return model
@classmethod
def from_pretrained(cls, model_name, weights_path=None, advprop=False,
in_channels=3, num_classes=1000, **override_params):
"""create an efficientnet model according to name.
Args:
model_name (str): Name for efficientnet.
weights_path (None or str):
str: path to pretrained weights file on the local disk.
None: use pretrained weights downloaded from the Internet.
advprop (bool):
Whether to load pretrained weights
trained with advprop (valid when weights_path is None).
in_channels (int): Input data's channel number.
num_classes (int):
Number of categories for classification.
It controls the output size for final linear layer.
override_params (other key word params):
Params to override model's global_params.
Optional key:
'width_coefficient', 'depth_coefficient',
'image_size', 'dropout_rate',
'num_classes', 'batch_norm_momentum',
'batch_norm_epsilon', 'drop_connect_rate',
'depth_divisor', 'min_depth'
Returns:
A pretrained efficientnet model.
"""
model = cls.from_name(model_name, num_classes = num_classes, **override_params)
load_pretrained_weights(model, model_name, weights_path=weights_path, load_fc=(num_classes == 1000), advprop=advprop)
model._change_in_channels(in_channels)
return model
@classmethod
def get_image_size(cls, model_name):
"""Get the input image size for a given efficientnet model.
Args:
model_name (str): Name for efficientnet.
Returns:
Input image size (resolution).
"""
cls._check_model_name_is_valid(model_name)
_, _, res, _ = efficientnet_params(model_name)
return res
@classmethod
def _check_model_name_is_valid(cls, model_name):
"""Validates model name.
Args:
model_name (str): Name for efficientnet.
Returns:
bool: Is a valid name or not.
"""
if model_name not in VALID_MODELS:
raise ValueError('model_name should be one of: ' + ', '.join(VALID_MODELS))
def _change_in_channels(self, in_channels):
"""Adjust model's first convolution layer to in_channels, if in_channels not equals 3.
Args:
in_channels (int): Input data's channel number.
"""
if in_channels != 3:
Conv2d = get_same_padding_conv2d(image_size = self._global_params.image_size)
out_channels = round_filters(32, self._global_params)
self._conv_stem = Conv2d(in_channels, out_channels, kernel_size=3, stride=2, bias=False)Introduced by Chollet in Xception: Deep Learning With Depthwise Separable Convolutions
Xception is a convolutional neural network architecture that relies solely on depthwise separable convolution layers.
Source: Xception: Deep Learning With Depthwise Separable Convolutions
"""Xception V1 model for Keras.
On ImageNet, this model gets to a top-1 validation accuracy of 0.790
and a top-5 validation accuracy of 0.945.
Do note that the input image format for this model is different than for
the VGG16 and ResNet models (299x299 instead of 224x224),
and that the input preprocessing function
is also different (same as Inception V3).
# Reference
- [Xception: Deep Learning with Depthwise Separable Convolutions](
https://arxiv.org/abs/1610.02357) (CVPR 2017)
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import os
import warnings
from . import get_submodules_from_kwargs
from . import imagenet_utils
from .imagenet_utils import decode_predictions
from .imagenet_utils import _obtain_input_shape
TF_WEIGHTS_PATH = (
'https://github.com/fchollet/deep-learning-models/'
'releases/download/v0.4/'
'xception_weights_tf_dim_ordering_tf_kernels.h5')
TF_WEIGHTS_PATH_NO_TOP = (
'https://github.com/fchollet/deep-learning-models/'
'releases/download/v0.4/'
'xception_weights_tf_dim_ordering_tf_kernels_notop.h5')
def Xception(include_top=True,
weights='imagenet',
input_tensor=None,
input_shape=None,
pooling=None,
classes=1000,
**kwargs):
"""Instantiates the Xception architecture.
Optionally loads weights pre-trained on ImageNet.
Note that the data format convention used by the model is
the one specified in your Keras config at `~/.keras/keras.json`.
Note that the default input image size for this model is 299x299.
# Arguments
include_top: whether to include the fully-connected
layer at the top of the network.
weights: one of `None` (random initialization),
'imagenet' (pre-training on ImageNet),
or the path to the weights file to be loaded.
input_tensor: optional Keras tensor
(i.e. output of `layers.Input()`)
to use as image input for the model.
input_shape: optional shape tuple, only to be specified
if `include_top` is False (otherwise the input shape
has to be `(299, 299, 3)`.
It should have exactly 3 inputs channels,
and width and height should be no smaller than 71.
E.g. `(150, 150, 3)` would be one valid value.
pooling: Optional pooling mode for feature extraction
when `include_top` is `False`.
- `None` means that the output of the model will be
the 4D tensor output of the
last convolutional block.
- `avg` means that global average pooling
will be applied to the output of the
last convolutional block, and thus
the output of the model will be a 2D tensor.
- `max` means that global max pooling will
be applied.
classes: optional number of classes to classify images
into, only to be specified if `include_top` is True,
and if no `weights` argument is specified.
# Returns
A Keras model instance.
# Raises
ValueError: in case of invalid argument for `weights`,
or invalid input shape.
RuntimeError: If attempting to run this model with a
backend that does not support separable convolutions.
"""
backend, layers, models, keras_utils = get_submodules_from_kwargs(kwargs)
if not (weights in {'imagenet', None} or os.path.exists(weights)):
raise ValueError('The `weights` argument should be either '
'`None` (random initialization), `imagenet` '
'(pre-training on ImageNet), '
'or the path to the weights file to be loaded.')
if weights == 'imagenet' and include_top and classes != 1000:
raise ValueError('If using `weights` as `"imagenet"` with `include_top`'
' as true, `classes` should be 1000')
# Determine proper input shape
input_shape = _obtain_input_shape(input_shape,
default_size=299,
min_size=71,
data_format=backend.image_data_format(),
require_flatten=include_top,
weights=weights)
if input_tensor is None:
img_input = layers.Input(shape=input_shape)
else:
if not backend.is_keras_tensor(input_tensor):
img_input = layers.Input(tensor=input_tensor, shape=input_shape)
else:
img_input = input_tensor
channel_axis = 1 if backend.image_data_format() == 'channels_first' else -1
x = layers.Conv2D(32, (3, 3),
strides=(2, 2),
use_bias=False,
name='block1_conv1')(img_input)
x = layers.BatchNormalization(axis=channel_axis, name='block1_conv1_bn')(x)
x = layers.Activation('relu', name='block1_conv1_act')(x)
x = layers.Conv2D(64, (3, 3), use_bias=False, name='block1_conv2')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block1_conv2_bn')(x)
x = layers.Activation('relu', name='block1_conv2_act')(x)
residual = layers.Conv2D(128, (1, 1),
strides=(2, 2),
padding='same',
use_bias=False)(x)
residual = layers.BatchNormalization(axis=channel_axis)(residual)
x = layers.SeparableConv2D(128, (3, 3),
padding='same',
use_bias=False,
name='block2_sepconv1')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block2_sepconv1_bn')(x)
x = layers.Activation('relu', name='block2_sepconv2_act')(x)
x = layers.SeparableConv2D(128, (3, 3),
padding='same',
use_bias=False,
name='block2_sepconv2')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block2_sepconv2_bn')(x)
x = layers.MaxPooling2D((3, 3),
strides=(2, 2),
padding='same',
name='block2_pool')(x)
x = layers.add([x, residual])
residual = layers.Conv2D(256, (1, 1), strides=(2, 2),
padding='same', use_bias=False)(x)
residual = layers.BatchNormalization(axis=channel_axis)(residual)
x = layers.Activation('relu', name='block3_sepconv1_act')(x)
x = layers.SeparableConv2D(256, (3, 3),
padding='same',
use_bias=False,
name='block3_sepconv1')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block3_sepconv1_bn')(x)
x = layers.Activation('relu', name='block3_sepconv2_act')(x)
x = layers.SeparableConv2D(256, (3, 3),
padding='same',
use_bias=False,
name='block3_sepconv2')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block3_sepconv2_bn')(x)
x = layers.MaxPooling2D((3, 3), strides=(2, 2),
padding='same',
name='block3_pool')(x)
x = layers.add([x, residual])
residual = layers.Conv2D(728, (1, 1),
strides=(2, 2),
padding='same',
use_bias=False)(x)
residual = layers.BatchNormalization(axis=channel_axis)(residual)
x = layers.Activation('relu', name='block4_sepconv1_act')(x)
x = layers.SeparableConv2D(728, (3, 3),
padding='same',
use_bias=False,
name='block4_sepconv1')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block4_sepconv1_bn')(x)
x = layers.Activation('relu', name='block4_sepconv2_act')(x)
x = layers.SeparableConv2D(728, (3, 3),
padding='same',
use_bias=False,
name='block4_sepconv2')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block4_sepconv2_bn')(x)
x = layers.MaxPooling2D((3, 3), strides=(2, 2),
padding='same',
name='block4_pool')(x)
x = layers.add([x, residual])
for i in range(8):
residual = x
prefix = 'block' + str(i + 5)
x = layers.Activation('relu', name=prefix + '_sepconv1_act')(x)
x = layers.SeparableConv2D(728, (3, 3),
padding='same',
use_bias=False,
name=prefix + '_sepconv1')(x)
x = layers.BatchNormalization(axis=channel_axis,
name=prefix + '_sepconv1_bn')(x)
x = layers.Activation('relu', name=prefix + '_sepconv2_act')(x)
x = layers.SeparableConv2D(728, (3, 3),
padding='same',
use_bias=False,
name=prefix + '_sepconv2')(x)
x = layers.BatchNormalization(axis=channel_axis,
name=prefix + '_sepconv2_bn')(x)
x = layers.Activation('relu', name=prefix + '_sepconv3_act')(x)
x = layers.SeparableConv2D(728, (3, 3),
padding='same',
use_bias=False,
name=prefix + '_sepconv3')(x)
x = layers.BatchNormalization(axis=channel_axis,
name=prefix + '_sepconv3_bn')(x)
x = layers.add([x, residual])
residual = layers.Conv2D(1024, (1, 1), strides=(2, 2),
padding='same', use_bias=False)(x)
residual = layers.BatchNormalization(axis=channel_axis)(residual)
x = layers.Activation('relu', name='block13_sepconv1_act')(x)
x = layers.SeparableConv2D(728, (3, 3),
padding='same',
use_bias=False,
name='block13_sepconv1')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block13_sepconv1_bn')(x)
x = layers.Activation('relu', name='block13_sepconv2_act')(x)
x = layers.SeparableConv2D(1024, (3, 3),
padding='same',
use_bias=False,
name='block13_sepconv2')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block13_sepconv2_bn')(x)
x = layers.MaxPooling2D((3, 3),
strides=(2, 2),
padding='same',
name='block13_pool')(x)
x = layers.add([x, residual])
x = layers.SeparableConv2D(1536, (3, 3),
padding='same',
use_bias=False,
name='block14_sepconv1')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block14_sepconv1_bn')(x)
x = layers.Activation('relu', name='block14_sepconv1_act')(x)
x = layers.SeparableConv2D(2048, (3, 3),
padding='same',
use_bias=False,
name='block14_sepconv2')(x)
x = layers.BatchNormalization(axis=channel_axis, name='block14_sepconv2_bn')(x)
x = layers.Activation('relu', name='block14_sepconv2_act')(x)
if include_top:
x = layers.GlobalAveragePooling2D(name='avg_pool')(x)
x = layers.Dense(classes, activation='softmax', name='predictions')(x)
else:
if pooling == 'avg':
x = layers.GlobalAveragePooling2D()(x)
elif pooling == 'max':
x = layers.GlobalMaxPooling2D()(x)
# Ensure that the model takes into account
# any potential predecessors of `input_tensor`.
if input_tensor is not None:
inputs = keras_utils.get_source_inputs(input_tensor)
else:
inputs = img_input
# Create model.
model = models.Model(inputs, x, name='xception')
# Load weights.
if weights == 'imagenet':
if include_top:
weights_path = keras_utils.get_file(
'xception_weights_tf_dim_ordering_tf_kernels.h5',
TF_WEIGHTS_PATH,
cache_subdir='models',
file_hash='0a58e3b7378bc2990ea3b43d5981f1f6')
else:
weights_path = keras_utils.get_file(
'xception_weights_tf_dim_ordering_tf_kernels_notop.h5',
TF_WEIGHTS_PATH_NO_TOP,
cache_subdir='models',
file_hash='b0042744bf5b25fce3cb969f33bebb97')
model.load_weights(weights_path)
if backend.backend() == 'theano':
keras_utils.convert_all_kernels_in_model(model)
elif weights is not None:
model.load_weights(weights)
return model
def preprocess_input(x, **kwargs):
"""Preprocesses a numpy array encoding a batch of images.
# Arguments
x: a 4D numpy array consists of RGB values within [0, 255].
# Returns
Preprocessed array.
"""
return imagenet_utils.preprocess_input(x, mode='tf', **kwargs)Introduced by Iandola et al. in SqueezeNet: AlexNet-level accuracy with 50x fewer parameters and <0.5MB model size
SqueezeNet is a convolutional neural network that employs design strategies to reduce the number of parameters, notably with the use of fire modules that "squeeze" parameters using 1x1 convolutions.
Source: SqueezeNet: AlexNet-level accuracy with 50x fewer parameters and <0.5MB model size
import torch
import torch.nn as nn
import torch.nn.init as init
from .utils import load_state_dict_from_url
__all__ = ['SqueezeNet', 'squeezenet1_0', 'squeezenet1_1']
model_urls = {
'squeezenet1_0': 'https://download.pytorch.org/models/squeezenet1_0-a815701f.pth',
'squeezenet1_1': 'https://download.pytorch.org/models/squeezenet1_1-f364aa15.pth',
}
class Fire(nn.Module):
def __init__(self, inplanes, squeeze_planes,
expand1x1_planes, expand3x3_planes):
super(Fire, self).__init__()
self.inplanes = inplanes
self.squeeze = nn.Conv2d(inplanes, squeeze_planes, kernel_size=1)
self.squeeze_activation = nn.ReLU(inplace=True)
self.expand1x1 = nn.Conv2d(squeeze_planes, expand1x1_planes,
kernel_size=1)
self.expand1x1_activation = nn.ReLU(inplace=True)
self.expand3x3 = nn.Conv2d(squeeze_planes, expand3x3_planes,
kernel_size=3, padding=1)
self.expand3x3_activation = nn.ReLU(inplace=True)
def forward(self, x):
x = self.squeeze_activation(self.squeeze(x))
return torch.cat([
self.expand1x1_activation(self.expand1x1(x)),
self.expand3x3_activation(self.expand3x3(x))
], 1)
class SqueezeNet(nn.Module):
def __init__(self, version='1_0', num_classes=1000):
super(SqueezeNet, self).__init__()
self.num_classes = num_classes
if version == '1_0':
self.features = nn.Sequential(
nn.Conv2d(3, 96, kernel_size=7, stride=2),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=3, stride=2, ceil_mode=True),
Fire(96, 16, 64, 64),
Fire(128, 16, 64, 64),
Fire(128, 32, 128, 128),
nn.MaxPool2d(kernel_size=3, stride=2, ceil_mode=True),
Fire(256, 32, 128, 128),
Fire(256, 48, 192, 192),
Fire(384, 48, 192, 192),
Fire(384, 64, 256, 256),
nn.MaxPool2d(kernel_size=3, stride=2, ceil_mode=True),
Fire(512, 64, 256, 256),
)
elif version == '1_1':
self.features = nn.Sequential(
nn.Conv2d(3, 64, kernel_size=3, stride=2),
nn.ReLU(inplace=True),
nn.MaxPool2d(kernel_size=3, stride=2, ceil_mode=True),
Fire(64, 16, 64, 64),
Fire(128, 16, 64, 64),
nn.MaxPool2d(kernel_size=3, stride=2, ceil_mode=True),
Fire(128, 32, 128, 128),
Fire(256, 32, 128, 128),
nn.MaxPool2d(kernel_size=3, stride=2, ceil_mode=True),
Fire(256, 48, 192, 192),
Fire(384, 48, 192, 192),
Fire(384, 64, 256, 256),
Fire(512, 64, 256, 256),
)
else:
# FIXME: Is this needed? SqueezeNet should only be called from the
# FIXME: squeezenet1_x() functions
# FIXME: This checking is not done for the other models
raise ValueError("Unsupported SqueezeNet version {version}:"
"1_0 or 1_1 expected".format(version=version))
# Final convolution is initialized differently from the rest
final_conv = nn.Conv2d(512, self.num_classes, kernel_size=1)
self.classifier = nn.Sequential(
nn.Dropout(p=0.5),
final_conv,
nn.ReLU(inplace=True),
nn.AdaptiveAvgPool2d((1, 1))
)
for m in self.modules():
if isinstance(m, nn.Conv2d):
if m is final_conv:
init.normal_(m.weight, mean=0.0, std=0.01)
else:
init.kaiming_uniform_(m.weight)
if m.bias is not None:
init.constant_(m.bias, 0)
def forward(self, x):
x = self.features(x)
x = self.classifier(x)
return torch.flatten(x, 1)
def _squeezenet(version, pretrained, progress, **kwargs):
model = SqueezeNet(version, **kwargs)
if pretrained:
arch = 'squeezenet' + version
state_dict = load_state_dict_from_url(model_urls[arch],
progress=progress)
model.load_state_dict(state_dict)
return model
def squeezenet1_0(pretrained=False, progress=True, **kwargs):
r"""SqueezeNet model architecture from the `"SqueezeNet: AlexNet-level
accuracy with 50x fewer parameters and <0.5MB model size"
<https://arxiv.org/abs/1602.07360>`_ paper.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _squeezenet('1_0', pretrained, progress, **kwargs)
def squeezenet1_1(pretrained=False, progress=True, **kwargs):
r"""SqueezeNet 1.1 model from the `official SqueezeNet repo
<https://github.com/DeepScale/SqueezeNet/tree/master/SqueezeNet_v1.1>`_.
SqueezeNet 1.1 has 2.4x less computation and slightly fewer parameters
than SqueezeNet 1.0, without sacrificing accuracy.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
"""
return _squeezenet('1_1', pretrained, progress, **kwargs)Introduced by Szegedy et al. in Rethinking the Inception Architecture for Computer Vision
Inception-v3 is a convolutional neural network architecture from the Inception family that makes several improvements including using Label Smoothing, Factorized 7 x 7 convolutions, and the use of an auxiliary classifer to propagate label information lower down the network (along with the use of batch normalization for layers in the sidehead).
Source: Rethinking the Inception Architecture for Computer Vision
from collections import namedtuple
import warnings
import torch
import torch.nn as nn
import torch.nn.functional as F
from torch.jit.annotations import Optional
from torch import Tensor
from .utils import load_state_dict_from_url
__all__ = ['Inception3', 'inception_v3', 'InceptionOutputs', '_InceptionOutputs']
model_urls = {
# Inception v3 ported from TensorFlow
'inception_v3_google': 'https://download.pytorch.org/models/inception_v3_google-1a9a5a14.pth',
}
InceptionOutputs = namedtuple('InceptionOutputs', ['logits', 'aux_logits'])
InceptionOutputs.__annotations__ = {'logits': torch.Tensor, 'aux_logits': Optional[torch.Tensor]}
# Script annotations failed with _GoogleNetOutputs = namedtuple ...
# _InceptionOutputs set here for backwards compat
_InceptionOutputs = InceptionOutputs
def inception_v3(pretrained=False, progress=True, **kwargs):
r"""Inception v3 model architecture from
`"Rethinking the Inception Architecture for Computer Vision" <http://arxiv.org/abs/1512.00567>`_.
.. note::
**Important**: In contrast to the other models the inception_v3 expects tensors with a size of
N x 3 x 299 x 299, so ensure your images are sized accordingly.
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
progress (bool): If True, displays a progress bar of the download to stderr
aux_logits (bool): If True, add an auxiliary branch that can improve training.
Default: *True*
transform_input (bool): If True, preprocesses the input according to the method with which it
was trained on ImageNet. Default: *False*
"""
if pretrained:
if 'transform_input' not in kwargs:
kwargs['transform_input'] = True
if 'aux_logits' in kwargs:
original_aux_logits = kwargs['aux_logits']
kwargs['aux_logits'] = True
else:
original_aux_logits = True
kwargs['init_weights'] = False # we are loading weights from a pretrained model
model = Inception3(**kwargs)
state_dict = load_state_dict_from_url(model_urls['inception_v3_google'],
progress=progress)
model.load_state_dict(state_dict)
if not original_aux_logits:
model.aux_logits = False
del model.AuxLogits
return model
return Inception3(**kwargs)
class Inception3(nn.Module):
def __init__(self, num_classes=1000, aux_logits=True, transform_input=False,
inception_blocks=None, init_weights=None):
super(Inception3, self).__init__()
if inception_blocks is None:
inception_blocks = [
BasicConv2d, InceptionA, InceptionB, InceptionC,
InceptionD, InceptionE, InceptionAux
]
if init_weights is None:
warnings.warn('The default weight initialization of inception_v3 will be changed in future releases of '
'torchvision. If you wish to keep the old behavior (which leads to long initialization times'
' due to scipy/scipy#11299), please set init_weights=True.', FutureWarning)
init_weights = True
assert len(inception_blocks) == 7
conv_block = inception_blocks[0]
inception_a = inception_blocks[1]
inception_b = inception_blocks[2]
inception_c = inception_blocks[3]
inception_d = inception_blocks[4]
inception_e = inception_blocks[5]
inception_aux = inception_blocks[6]
self.aux_logits = aux_logits
self.transform_input = transform_input
self.Conv2d_1a_3x3 = conv_block(3, 32, kernel_size=3, stride=2)
self.Conv2d_2a_3x3 = conv_block(32, 32, kernel_size=3)
self.Conv2d_2b_3x3 = conv_block(32, 64, kernel_size=3, padding=1)
self.maxpool1 = nn.MaxPool2d(kernel_size=3, stride=2)
self.Conv2d_3b_1x1 = conv_block(64, 80, kernel_size=1)
self.Conv2d_4a_3x3 = conv_block(80, 192, kernel_size=3)
self.maxpool2 = nn.MaxPool2d(kernel_size=3, stride=2)
self.Mixed_5b = inception_a(192, pool_features=32)
self.Mixed_5c = inception_a(256, pool_features=64)
self.Mixed_5d = inception_a(288, pool_features=64)
self.Mixed_6a = inception_b(288)
self.Mixed_6b = inception_c(768, channels_7x7=128)
self.Mixed_6c = inception_c(768, channels_7x7=160)
self.Mixed_6d = inception_c(768, channels_7x7=160)
self.Mixed_6e = inception_c(768, channels_7x7=192)
if aux_logits:
self.AuxLogits = inception_aux(768, num_classes)
self.Mixed_7a = inception_d(768)
self.Mixed_7b = inception_e(1280)
self.Mixed_7c = inception_e(2048)
self.avgpool = nn.AdaptiveAvgPool2d((1, 1))
self.dropout = nn.Dropout()
self.fc = nn.Linear(2048, num_classes)
if init_weights:
for m in self.modules():
if isinstance(m, nn.Conv2d) or isinstance(m, nn.Linear):
import scipy.stats as stats
stddev = m.stddev if hasattr(m, 'stddev') else 0.1
X = stats.truncnorm(-2, 2, scale=stddev)
values = torch.as_tensor(X.rvs(m.weight.numel()), dtype=m.weight.dtype)
values = values.view(m.weight.size())
with torch.no_grad():
m.weight.copy_(values)
elif isinstance(m, nn.BatchNorm2d):
nn.init.constant_(m.weight, 1)
nn.init.constant_(m.bias, 0)
def _transform_input(self, x):
if self.transform_input:
x_ch0 = torch.unsqueeze(x[:, 0], 1) * (0.229 / 0.5) + (0.485 - 0.5) / 0.5
x_ch1 = torch.unsqueeze(x[:, 1], 1) * (0.224 / 0.5) + (0.456 - 0.5) / 0.5
x_ch2 = torch.unsqueeze(x[:, 2], 1) * (0.225 / 0.5) + (0.406 - 0.5) / 0.5
x = torch.cat((x_ch0, x_ch1, x_ch2), 1)
return x
def _forward(self, x):
# N x 3 x 299 x 299
x = self.Conv2d_1a_3x3(x)
# N x 32 x 149 x 149
x = self.Conv2d_2a_3x3(x)
# N x 32 x 147 x 147
x = self.Conv2d_2b_3x3(x)
# N x 64 x 147 x 147
x = self.maxpool1(x)
# N x 64 x 73 x 73
x = self.Conv2d_3b_1x1(x)
# N x 80 x 73 x 73
x = self.Conv2d_4a_3x3(x)
# N x 192 x 71 x 71
x = self.maxpool2(x)
# N x 192 x 35 x 35
x = self.Mixed_5b(x)
# N x 256 x 35 x 35
x = self.Mixed_5c(x)
# N x 288 x 35 x 35
x = self.Mixed_5d(x)
# N x 288 x 35 x 35
x = self.Mixed_6a(x)
# N x 768 x 17 x 17
x = self.Mixed_6b(x)
# N x 768 x 17 x 17
x = self.Mixed_6c(x)
# N x 768 x 17 x 17
x = self.Mixed_6d(x)
# N x 768 x 17 x 17
x = self.Mixed_6e(x)
# N x 768 x 17 x 17
aux_defined = self.training and self.aux_logits
if aux_defined:
aux = self.AuxLogits(x)
else:
aux = None
# N x 768 x 17 x 17
x = self.Mixed_7a(x)
# N x 1280 x 8 x 8
x = self.Mixed_7b(x)
# N x 2048 x 8 x 8
x = self.Mixed_7c(x)
# N x 2048 x 8 x 8
# Adaptive average pooling
x = self.avgpool(x)
# N x 2048 x 1 x 1
x = self.dropout(x)
# N x 2048 x 1 x 1
x = torch.flatten(x, 1)
# N x 2048
x = self.fc(x)
# N x 1000 (num_classes)
return x, aux
@torch.jit.unused
def eager_outputs(self, x, aux):
# type: (Tensor, Optional[Tensor]) -> InceptionOutputs
if self.training and self.aux_logits:
return InceptionOutputs(x, aux)
else:
return x
def forward(self, x):
x = self._transform_input(x)
x, aux = self._forward(x)
aux_defined = self.training and self.aux_logits
if torch.jit.is_scripting():
if not aux_defined:
warnings.warn("Scripted Inception3 always returns Inception3 Tuple")
return InceptionOutputs(x, aux)
else:
return self.eager_outputs(x, aux)
class InceptionA(nn.Module):
def __init__(self, in_channels, pool_features, conv_block=None):
super(InceptionA, self).__init__()
if conv_block is None:
conv_block = BasicConv2d
self.branch1x1 = conv_block(in_channels, 64, kernel_size=1)
self.branch5x5_1 = conv_block(in_channels, 48, kernel_size=1)
self.branch5x5_2 = conv_block(48, 64, kernel_size=5, padding=2)
self.branch3x3dbl_1 = conv_block(in_channels, 64, kernel_size=1)
self.branch3x3dbl_2 = conv_block(64, 96, kernel_size=3, padding=1)
self.branch3x3dbl_3 = conv_block(96, 96, kernel_size=3, padding=1)
self.branch_pool = conv_block(in_channels, pool_features, kernel_size=1)
def _forward(self, x):
branch1x1 = self.branch1x1(x)
branch5x5 = self.branch5x5_1(x)
branch5x5 = self.branch5x5_2(branch5x5)
branch3x3dbl = self.branch3x3dbl_1(x)
branch3x3dbl = self.branch3x3dbl_2(branch3x3dbl)
branch3x3dbl = self.branch3x3dbl_3(branch3x3dbl)
branch_pool = F.avg_pool2d(x, kernel_size=3, stride=1, padding=1)
branch_pool = self.branch_pool(branch_pool)
outputs = [branch1x1, branch5x5, branch3x3dbl, branch_pool]
return outputs
def forward(self, x):
outputs = self._forward(x)
return torch.cat(outputs, 1)
class InceptionB(nn.Module):
def __init__(self, in_channels, conv_block=None):
super(InceptionB, self).__init__()
if conv_block is None:
conv_block = BasicConv2d
self.branch3x3 = conv_block(in_channels, 384, kernel_size=3, stride=2)
self.branch3x3dbl_1 = conv_block(in_channels, 64, kernel_size=1)
self.branch3x3dbl_2 = conv_block(64, 96, kernel_size=3, padding=1)
self.branch3x3dbl_3 = conv_block(96, 96, kernel_size=3, stride=2)
def _forward(self, x):
branch3x3 = self.branch3x3(x)
branch3x3dbl = self.branch3x3dbl_1(x)
branch3x3dbl = self.branch3x3dbl_2(branch3x3dbl)
branch3x3dbl = self.branch3x3dbl_3(branch3x3dbl)
branch_pool = F.max_pool2d(x, kernel_size=3, stride=2)
outputs = [branch3x3, branch3x3dbl, branch_pool]
return outputs
def forward(self, x):
outputs = self._forward(x)
return torch.cat(outputs, 1)
class InceptionC(nn.Module):
def __init__(self, in_channels, channels_7x7, conv_block=None):
super(InceptionC, self).__init__()
if conv_block is None:
conv_block = BasicConv2d
self.branch1x1 = conv_block(in_channels, 192, kernel_size=1)
c7 = channels_7x7
self.branch7x7_1 = conv_block(in_channels, c7, kernel_size=1)
self.branch7x7_2 = conv_block(c7, c7, kernel_size=(1, 7), padding=(0, 3))
self.branch7x7_3 = conv_block(c7, 192, kernel_size=(7, 1), padding=(3, 0))
self.branch7x7dbl_1 = conv_block(in_channels, c7, kernel_size=1)
self.branch7x7dbl_2 = conv_block(c7, c7, kernel_size=(7, 1), padding=(3, 0))
self.branch7x7dbl_3 = conv_block(c7, c7, kernel_size=(1, 7), padding=(0, 3))
self.branch7x7dbl_4 = conv_block(c7, c7, kernel_size=(7, 1), padding=(3, 0))
self.branch7x7dbl_5 = conv_block(c7, 192, kernel_size=(1, 7), padding=(0, 3))
self.branch_pool = conv_block(in_channels, 192, kernel_size=1)
def _forward(self, x):
branch1x1 = self.branch1x1(x)
branch7x7 = self.branch7x7_1(x)
branch7x7 = self.branch7x7_2(branch7x7)
branch7x7 = self.branch7x7_3(branch7x7)
branch7x7dbl = self.branch7x7dbl_1(x)
branch7x7dbl = self.branch7x7dbl_2(branch7x7dbl)
branch7x7dbl = self.branch7x7dbl_3(branch7x7dbl)
branch7x7dbl = self.branch7x7dbl_4(branch7x7dbl)
branch7x7dbl = self.branch7x7dbl_5(branch7x7dbl)
branch_pool = F.avg_pool2d(x, kernel_size=3, stride=1, padding=1)
branch_pool = self.branch_pool(branch_pool)
outputs = [branch1x1, branch7x7, branch7x7dbl, branch_pool]
return outputs
def forward(self, x):
outputs = self._forward(x)
return torch.cat(outputs, 1)
class InceptionD(nn.Module):
def __init__(self, in_channels, conv_block=None):
super(InceptionD, self).__init__()
if conv_block is None:
conv_block = BasicConv2d
self.branch3x3_1 = conv_block(in_channels, 192, kernel_size=1)
self.branch3x3_2 = conv_block(192, 320, kernel_size=3, stride=2)
self.branch7x7x3_1 = conv_block(in_channels, 192, kernel_size=1)
self.branch7x7x3_2 = conv_block(192, 192, kernel_size=(1, 7), padding=(0, 3))
self.branch7x7x3_3 = conv_block(192, 192, kernel_size=(7, 1), padding=(3, 0))
self.branch7x7x3_4 = conv_block(192, 192, kernel_size=3, stride=2)
def _forward(self, x):
branch3x3 = self.branch3x3_1(x)
branch3x3 = self.branch3x3_2(branch3x3)
branch7x7x3 = self.branch7x7x3_1(x)
branch7x7x3 = self.branch7x7x3_2(branch7x7x3)
branch7x7x3 = self.branch7x7x3_3(branch7x7x3)
branch7x7x3 = self.branch7x7x3_4(branch7x7x3)
branch_pool = F.max_pool2d(x, kernel_size=3, stride=2)
outputs = [branch3x3, branch7x7x3, branch_pool]
return outputs
def forward(self, x):
outputs = self._forward(x)
return torch.cat(outputs, 1)
class InceptionE(nn.Module):
def __init__(self, in_channels, conv_block=None):
super(InceptionE, self).__init__()
if conv_block is None:
conv_block = BasicConv2d
self.branch1x1 = conv_block(in_channels, 320, kernel_size=1)
self.branch3x3_1 = conv_block(in_channels, 384, kernel_size=1)
self.branch3x3_2a = conv_block(384, 384, kernel_size=(1, 3), padding=(0, 1))
self.branch3x3_2b = conv_block(384, 384, kernel_size=(3, 1), padding=(1, 0))
self.branch3x3dbl_1 = conv_block(in_channels, 448, kernel_size=1)
self.branch3x3dbl_2 = conv_block(448, 384, kernel_size=3, padding=1)
self.branch3x3dbl_3a = conv_block(384, 384, kernel_size=(1, 3), padding=(0, 1))
self.branch3x3dbl_3b = conv_block(384, 384, kernel_size=(3, 1), padding=(1, 0))
self.branch_pool = conv_block(in_channels, 192, kernel_size=1)
def _forward(self, x):
branch1x1 = self.branch1x1(x)
branch3x3 = self.branch3x3_1(x)
branch3x3 = [
self.branch3x3_2a(branch3x3),
self.branch3x3_2b(branch3x3),
]
branch3x3 = torch.cat(branch3x3, 1)
branch3x3dbl = self.branch3x3dbl_1(x)
branch3x3dbl = self.branch3x3dbl_2(branch3x3dbl)
branch3x3dbl = [
self.branch3x3dbl_3a(branch3x3dbl),
self.branch3x3dbl_3b(branch3x3dbl),
]
branch3x3dbl = torch.cat(branch3x3dbl, 1)
branch_pool = F.avg_pool2d(x, kernel_size=3, stride=1, padding=1)
branch_pool = self.branch_pool(branch_pool)
outputs = [branch1x1, branch3x3, branch3x3dbl, branch_pool]
return outputs
def forward(self, x):
outputs = self._forward(x)
return torch.cat(outputs, 1)
class InceptionAux(nn.Module):
def __init__(self, in_channels, num_classes, conv_block=None):
super(InceptionAux, self).__init__()
if conv_block is None:
conv_block = BasicConv2d
self.conv0 = conv_block(in_channels, 128, kernel_size=1)
self.conv1 = conv_block(128, 768, kernel_size=5)
self.conv1.stddev = 0.01
self.fc = nn.Linear(768, num_classes)
self.fc.stddev = 0.001
def forward(self, x):
# N x 768 x 17 x 17
x = F.avg_pool2d(x, kernel_size=5, stride=3)
# N x 768 x 5 x 5
x = self.conv0(x)
# N x 128 x 5 x 5
x = self.conv1(x)
# N x 768 x 1 x 1
# Adaptive average pooling
x = F.adaptive_avg_pool2d(x, (1, 1))
# N x 768 x 1 x 1
x = torch.flatten(x, 1)
# N x 768
x = self.fc(x)
# N x 1000
return x
class BasicConv2d(nn.Module):
def __init__(self, in_channels, out_channels, **kwargs):
super(BasicConv2d, self).__init__()
self.conv = nn.Conv2d(in_channels, out_channels, bias=False, **kwargs)
self.bn = nn.BatchNorm2d(out_channels, eps=0.001)
def forward(self, x):
x = self.conv(x)
x = self.bn(x)
return F.relu(x, inplace=True)
LeNet is a classic convolutional neural network employing the use of convolutions, pooling and fully connected layers. It was used for the handwritten digit recognition task with the MNIST dataset. The architectural design served as inspiration for future networks such as AlexNet and VGG.
LeNet is a convolutional neural network structure proposed by Yann LeCun et al. in 1989. In general, LeNet refers to lenet-5 and is a simple convolutional neural network. Convolutional neural networks are a kind of feed-forward neural network whose artificial neurons can respond to a part of the surrounding cells in the coverage range and perform well in large-scale image processing.
Tecnhical Papers related to LeNet
Code Sample implementing LeNet
import torch.nn as nn
from collections import OrderedDict
class C1(nn.Module):
def __init__(self):
super(C1, self).__init__()
self.c1 = nn.Sequential(OrderedDict([
('c1', nn.Conv2d(1, 6, kernel_size=(5, 5))),
('relu1', nn.ReLU()),
('s1', nn.MaxPool2d(kernel_size=(2, 2), stride=2))
]))
def forward(self, img):
output = self.c1(img)
return output
class C2(nn.Module):
def __init__(self):
super(C2, self).__init__()
self.c2 = nn.Sequential(OrderedDict([
('c2', nn.Conv2d(6, 16, kernel_size=(5, 5))),
('relu2', nn.ReLU()),
('s2', nn.MaxPool2d(kernel_size=(2, 2), stride=2))
]))
def forward(self, img):
output = self.c2(img)
return output
class C3(nn.Module):
def __init__(self):
super(C3, self).__init__()
self.c3 = nn.Sequential(OrderedDict([
('c3', nn.Conv2d(16, 120, kernel_size=(5, 5))),
('relu3', nn.ReLU())
]))
def forward(self, img):
output = self.c3(img)
return output
class F4(nn.Module):
def __init__(self):
super(F4, self).__init__()
self.f4 = nn.Sequential(OrderedDict([
('f4', nn.Linear(120, 84)),
('relu4', nn.ReLU())
]))
def forward(self, img):
output = self.f4(img)
return output
class F5(nn.Module):
def __init__(self):
super(F5, self).__init__()
self.f5 = nn.Sequential(OrderedDict([
('f5', nn.Linear(84, 10)),
('sig5', nn.LogSoftmax(dim=-1))
]))
def forward(self, img):
output = self.f5(img)
return output
class LeNet5(nn.Module):
"""
Input - 1x32x32
Output - 10
"""
def __init__(self):
super(LeNet5, self).__init__()
self.c1 = C1()
self.c2_1 = C2()
self.c2_2 = C2()
self.c3 = C3()
self.f4 = F4()
self.f5 = F5()
def forward(self, img):
output = self.c1(img)
x = self.c2_1(output)
output = self.c2_2(output)
output += x
output = self.c3(output)
output = output.view(img.size(0), -1)
output = self.f4(output)
output = self.f5(output)
return outputfrom lenet import LeNet5
import torch
import torch.nn as nn
import torch.optim as optim
from torchvision.datasets.mnist import MNIST
import torchvision.transforms as transforms
from torch.utils.data import DataLoader
import visdom
import onnx
viz = visdom.Visdom()
data_train = MNIST('./data/mnist',
download=True,
transform=transforms.Compose([
transforms.Resize((32, 32)),
transforms.ToTensor()]))
data_test = MNIST('./data/mnist',
train=False,
download=True,
transform=transforms.Compose([
transforms.Resize((32, 32)),
transforms.ToTensor()]))
data_train_loader = DataLoader(data_train, batch_size=256, shuffle=True, num_workers=8)
data_test_loader = DataLoader(data_test, batch_size=1024, num_workers=8)
net = LeNet5()
criterion = nn.CrossEntropyLoss()
optimizer = optim.Adam(net.parameters(), lr=2e-3)
cur_batch_win = None
cur_batch_win_opts = {
'title': 'Epoch Loss Trace',
'xlabel': 'Batch Number',
'ylabel': 'Loss',
'width': 1200,
'height': 600,
}
def train(epoch):
global cur_batch_win
net.train()
loss_list, batch_list = [], []
for i, (images, labels) in enumerate(data_train_loader):
optimizer.zero_grad()
output = net(images)
loss = criterion(output, labels)
loss_list.append(loss.detach().cpu().item())
batch_list.append(i+1)
if i % 10 == 0:
print('Train - Epoch %d, Batch: %d, Loss: %f' % (epoch, i, loss.detach().cpu().item()))
# Update Visualization
if viz.check_connection():
cur_batch_win = viz.line(torch.Tensor(loss_list), torch.Tensor(batch_list),
win=cur_batch_win, name='current_batch_loss',
update=(None if cur_batch_win is None else 'replace'),
opts=cur_batch_win_opts)
loss.backward()
optimizer.step()
def test():
net.eval()
total_correct = 0
avg_loss = 0.0
for i, (images, labels) in enumerate(data_test_loader):
output = net(images)
avg_loss += criterion(output, labels).sum()
pred = output.detach().max(1)[1]
total_correct += pred.eq(labels.view_as(pred)).sum()
avg_loss /= len(data_test)
print('Test Avg. Loss: %f, Accuracy: %f' % (avg_loss.detach().cpu().item(), float(total_correct) / len(data_test)))
def train_and_test(epoch):
train(epoch)
test()
dummy_input = torch.randn(1, 1, 32, 32, requires_grad=True)
torch.onnx.export(net, dummy_input, "lenet.onnx")
onnx_model = onnx.load("lenet.onnx")
onnx.checker.check_model(onnx_model)
def main():
for e in range(1, 16):
train_and_test(e)
if __name__ == '__main__':
main()Introduced by Howard et al. in MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications
MobileNet is a type of convolutional neural network designed for mobile and embedded vision applications. They are based on a streamlined architecture that uses depthwise separable convolutions to build lightweight deep neural networks that can have low latency for mobile and embedded devices.
Source: MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications
"""
MobileNet for ImageNet-1K, implemented in PyTorch.
Original paper: 'MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications,'
https://arxiv.org/abs/1704.04861.
"""
__all__ = ['MobileNet', 'mobilenet_w1', 'mobilenet_w3d4', 'mobilenet_wd2', 'mobilenet_wd4', 'get_mobilenet']
import os
import torch.nn as nn
from .common import conv3x3_block, dwsconv3x3_block
class MobileNet(nn.Module):
"""
MobileNet model from 'MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications,'
https://arxiv.org/abs/1704.04861.
Parameters:
----------
channels : list of list of int
Number of output channels for each unit.
first_stage_stride : bool
Whether stride is used at the first stage.
in_channels : int, default 3
Number of input channels.
in_size : tuple of two ints, default (224, 224)
Spatial size of the expected input image.
num_classes : int, default 1000
Number of classification classes.
"""
def __init__(self,
channels,
first_stage_stride,
in_channels=3,
in_size=(224, 224),
num_classes=1000):
super(MobileNet, self).__init__()
self.in_size = in_size
self.num_classes = num_classes
self.features = nn.Sequential()
init_block_channels = channels[0][0]
self.features.add_module("init_block", conv3x3_block(
in_channels=in_channels,
out_channels=init_block_channels,
stride=2))
in_channels = init_block_channels
for i, channels_per_stage in enumerate(channels[1:]):
stage = nn.Sequential()
for j, out_channels in enumerate(channels_per_stage):
stride = 2 if (j == 0) and ((i != 0) or first_stage_stride) else 1
stage.add_module("unit{}".format(j + 1), dwsconv3x3_block(
in_channels=in_channels,
out_channels=out_channels,
stride=stride))
in_channels = out_channels
self.features.add_module("stage{}".format(i + 1), stage)
self.features.add_module("final_pool", nn.AvgPool2d(
kernel_size=7,
stride=1))
self.output = nn.Linear(
in_features=in_channels,
out_features=num_classes)
self._init_params()
def _init_params(self):
for name, module in self.named_modules():
if 'dw_conv.conv' in name:
nn.init.kaiming_normal_(module.weight, mode='fan_in')
elif name == 'init_block.conv' or 'pw_conv.conv' in name:
nn.init.kaiming_normal_(module.weight, mode='fan_out')
elif 'bn' in name:
nn.init.constant_(module.weight, 1)
nn.init.constant_(module.bias, 0)
elif 'output' in name:
nn.init.kaiming_normal_(module.weight, mode='fan_out')
nn.init.constant_(module.bias, 0)
def forward(self, x):
x = self.features(x)
x = x.view(x.size(0), -1)
x = self.output(x)
return x
def get_mobilenet(width_scale,
model_name=None,
pretrained=False,
root=os.path.join("~", ".torch", "models"),
**kwargs):
"""
Create MobileNet model with specific parameters.
Parameters:
----------
width_scale : float
Scale factor for width of layers.
model_name : str or None, default None
Model name for loading pretrained model.
pretrained : bool, default False
Whether to load the pretrained weights for model.
root : str, default '~/.torch/models'
Location for keeping the model parameters.
"""
channels = [[32], [64], [128, 128], [256, 256], [512, 512, 512, 512, 512, 512], [1024, 1024]]
first_stage_stride = False
if width_scale != 1.0:
channels = [[int(cij * width_scale) for cij in ci] for ci in channels]
net = MobileNet(
channels=channels,
first_stage_stride=first_stage_stride,
**kwargs)
if pretrained:
if (model_name is None) or (not model_name):
raise ValueError("Parameter `model_name` should be properly initialized for loading pretrained model.")
from .model_store import download_model
download_model(
net=net,
model_name=model_name,
local_model_store_dir_path=root)
return net
def mobilenet_w1(**kwargs):
"""
1.0 MobileNet-224 model from 'MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications,'
https://arxiv.org/abs/1704.04861.
Parameters:
----------
pretrained : bool, default False
Whether to load the pretrained weights for model.
root : str, default '~/.torch/models'
Location for keeping the model parameters.
"""
return get_mobilenet(width_scale=1.0, model_name="mobilenet_w1", **kwargs)
def mobilenet_w3d4(**kwargs):
"""
0.75 MobileNet-224 model from 'MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications,'
https://arxiv.org/abs/1704.04861.
Parameters:
----------
pretrained : bool, default False
Whether to load the pretrained weights for model.
root : str, default '~/.torch/models'
Location for keeping the model parameters.
"""
return get_mobilenet(width_scale=0.75, model_name="mobilenet_w3d4", **kwargs)
def mobilenet_wd2(**kwargs):
"""
0.5 MobileNet-224 model from 'MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications,'
https://arxiv.org/abs/1704.04861.
Parameters:
----------
pretrained : bool, default False
Whether to load the pretrained weights for model.
root : str, default '~/.torch/models'
Location for keeping the model parameters.
"""
return get_mobilenet(width_scale=0.5, model_name="mobilenet_wd2", **kwargs)
def mobilenet_wd4(**kwargs):
"""
0.25 MobileNet-224 model from 'MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications,'
https://arxiv.org/abs/1704.04861.
Parameters:
----------
pretrained : bool, default False
Whether to load the pretrained weights for model.
root : str, default '~/.torch/models'
Location for keeping the model parameters.
"""
return get_mobilenet(width_scale=0.25, model_name="mobilenet_wd4", **kwargs)
def _calc_width(net):
import numpy as np
net_params = filter(lambda p: p.requires_grad, net.parameters())
weight_count = 0
for param in net_params:
weight_count += np.prod(param.size())
return weight_count
def _test():
import torch
pretrained = False
models = [
mobilenet_w1,
mobilenet_w3d4,
mobilenet_wd2,
mobilenet_wd4,
]
for model in models:
net = model(pretrained=pretrained)
# net.train()
net.eval()
weight_count = _calc_width(net)
print("m={}, {}".format(model.__name__, weight_count))
assert (model != mobilenet_w1 or weight_count == 4231976)
assert (model != mobilenet_w3d4 or weight_count == 2585560)
assert (model != mobilenet_wd2 or weight_count == 1331592)
assert (model != mobilenet_wd4 or weight_count == 470072)
x = torch.randn(1, 3, 224, 224)
y = net(x)
y.sum().backward()
assert (tuple(y.size()) == (1, 1000))
if __name__ == "__main__":
_test()Data Science (a.k.a. Data Mining) is about explaining the past and predicting the future by means of data analysis. Data science is a multi-disciplinary field which combines statistics, machine learning, artificial intelligence and database technology.
Classification is a data science task of predicting the value of a categorical variable (target or class) by building a model based on one or more numerical and/or categorical variables (predictors or attributes).
Four main groups of classification algorithms are:
ZeroR is the simplest classification method which relies on the target and ignores all predictors. ZeroR classifier simply predicts the majority category (class). Although there is no predictability power in ZeroR, it is useful for determining a baseline performance as a benchmark for other classification methods.
OneR, short for "One Rule", is a simple, yet accurate, classification algorithm that generates one rule for each predictor in the data, then selects the rule with the smallest total error as its "one rule". To create a rule for a predictor, we construct a frequency table for each predictor against the target. It has been shown that OneR produces rules only slightly less accurate than state-of-the-art classification algorithms while producing rules that are simple for humans to interpret.
he Naive Bayesian classifier is based on Bayes’ theorem with the independence assumptions between predictors. A Naive Bayesian model is easy to build, with no complicated iterative parameter estimation which makes it particularly useful for very large datasets. Despite its simplicity, the Naive Bayesian classifier often does surprisingly well and is widely used because it often outperforms more sophisticated classification methods.
Decision tree builds classification or regression models in the form of a tree structure. It breaks down a dataset into smaller and smaller subsets while at the same time an associated decision tree is incrementally developed. The final result is a tree with decision nodes and leaf nodes. A decision node (e.g., Outlook) has two or more branches (e.g., Sunny, Overcast and Rainy). Leaf node (e.g., Play) represents a classification or decision. The topmost decision node in a tree which corresponds to the best predictor called root node. Decision trees can handle both categorical and numerical data.
inear Discriminant Analysis (LDA) is a classification method originally developed in 1936 by R. A. Fisher. It is simple, mathematically robust and often produces models whose accuracy is as good as more complex methods.
Logistic regression predicts the probability of an outcome that can only have two values (i.e. a dichotomy). The prediction is based on the use of one or several predictors (numerical and categorical). A linear regression is not appropriate for predicting the value of a binary variable for two reasons:
- A linear regression will predict values outside the acceptable range (e.g. predicting probabilities outside the range 0 to 1)
- Since the dichotomous experiments can only have one of two possible values for each experiment, the residuals will not be normally distributed about the predicted line.
On the other hand, a logistic regression produces a logistic curve, which is limited to values between 0 and 1. Logistic regression is similar to a linear regression, but the curve is constructed using the natural logarithm of the “odds” of the target variable, rather than the probability. Moreover, the predictors do not have to be normally distributed or have equal variance in each group.
The k-nearest neighbors algorithm (k-NN) is a non-parametric machine learning method first developed by Evelyn Fix and Joseph Hodges in 1951, and later expanded by Thomas Cover. It is used for classification and regression. In both cases, the input consists of the k closest training examples in feature space. The output depends on whether k-NN is used for classification or regression:
In k-NN classification, the output is a class membership. An object is classified by a plurality vote of its neighbors, with the object being assigned to the class most common among its k nearest neighbors (k is a positive integer, typically small). If k = 1, then the object is simply assigned to the class of that single nearest neighbor. In k-NN regression, the output is the property value for the object. This value is the average of the values of k nearest neighbors.
k-NN is a type of instance-based learning, or lazy learning, where the function is only approximated locally and all computation is deferred until function evaluation. Since this algorithm relies on distance for classification, if the features represent different physical units or come in vastly different scales then normalizing the training data can improve its accuracy dramatically.
An artificial neutral network (ANN) is a system that is based on the biological neural network, such as the brain. The brain has approximately 100 billion neurons, which communicate through electro-chemical signals. The neurons are connected through junctions called synapses. Each neuron receives thousands of connections with other neurons, constantly receiving incoming signals to reach the cell body. If the resulting sum of the signals surpasses a certain threshold, a response is sent through the axon. The ANN attempts to recreate the computational mirror of the biological neural network, although it is not comparable since the number and complexity of neurons and the used in a biological neural network is many times more than those in an artificial neutral network.
An ANN is comprised of a network of artificial neurons (also known as "nodes"). These nodes are connected to each other, and the strength of their connections to one another is assigned a value based on their strength: inhibition (maximum being -1.0) or excitation (maximum being +1.0). If the value of the connection is high, then it indicates that there is a strong connection. Within each node's design, a transfer function is built in. There are three types of neurons in an ANN, input nodes, hidden nodes, and output nodes.
A Support Vector Machine (SVM) performs classification by finding the hyperplane that maximizes the margin between the two classes. The vectors (cases) that define the hyperplane are the support vectors.
Simple linear regression is a statistical method that allows us to summarize and study relationships between two continuous (quantitative) variables:
- One variable, denoted x, is regarded as the predictor, explanatory, or independent variable.
- The other variable, denoted y, is regarded as the response, outcome, or dependent variable.
Because the other terms are used less frequently today, we'll use the "predictor" and "response" terms to refer to the variables encountered in this course. The other terms are mentioned only to make you aware of them should you encounter them. Simple linear regression gets its adjective "simple," because it concerns the study of only one predictor variable. In contrast, multiple linear regression, which we study later in this course, gets its adjective "multiple," because it concerns the study of two or more predictor variables.
Multiple linear regression is a regression model that estimates the relationship between a quantitative dependent variable and two or more independent variables using a straight line. Multiple linear regression attempts to model the relationship between two or more explanatory variables and a response variable by fitting a linear equation to observed data.
Logistic regression is a classification algorithm. It is used to predict a binary outcome based on a set of independent variables. A binary outcome is one where there are only two possible scenarios—either the event happens (1) or it does not happen (0). Independent variables are those variables or factors which may influence the outcome (or dependent variable). So: Logistic regression is the correct type of analysis to use when you’re working with binary data. You know you’re dealing with binary data when the output or dependent variable is dichotomous or categorical in nature; in other words, if it fits into one of two categories (such as “yes” or “no”, “pass” or “fail”, and so on).