Alexnet网络详解代码：手撕Alexnet卷积神经网络-pytorch-详细注释版（可以直接替换自己数据集）-直接放置自己的数据集就能直接跑。跑的代码有问题的可以在评论区指出，看到了会回复。训练代码和预测代码均有。_小馨馨的小翟的博客-CSDN博客_alexnet神经网络代码
VGG网络详解代码： 手撕VGG卷积神经网络-pytorch-详细注释版（可以直接替换自己数据集）-直接放置自己的数据集就能直接跑。跑的代码有问题的可以在评论区指出，看到了会回复。训练代码和预测代码均有。_小馨馨的小翟的博客-CSDN博客
Resnet网络详解代码： 手撕Resnet卷积神经网络-pytorch-详细注释版（可以直接替换自己数据集）-直接放置自己的数据集就能直接跑。跑的代码有问题的可以在评论区指出，看到了会回复。训练代码和预测代码均有。_小馨馨的小翟的博客-CSDN博客
Googlenet网络详解代码：手撕Googlenet卷积神经网络-pytorch-详细注释版（可以直接替换自己数据集）-直接放置自己的数据集就能直接跑。跑的代码有问题的可以在评论区指出，看到了会回复。训练代码和预测代码均有。_小馨馨的小翟的博客-CSDN博客_cnn测试集准确率低
集成学习模型融合网络详解代码：
集成学习-模型融合（Lenet，Alexnet，Vgg）三个模型进行融合-附源代码-宇宙的尽头一定是融合模型而不是单个模型。_小馨馨的小翟的博客-CSDN博客_torch模型融合
深度学习常用数据增强，数据扩充代码数据缩放代码：
深度学习数据增强方法-内含（亮度增强，对比度增强，旋转图图像，翻转图像，仿射变化扩充图像，错切变化扩充图像，HSV数据增强）七种方式进行增强-每种扩充一张实现7倍扩）+ 图像缩放代码-批量_小馨馨的小翟的博客-CSDN博客_训练数据增强
Resnet（Deep residual network, ResNet），深度残差神经网络，卷积神经网络历史在具有划时代意义的神经网络。与Alexnet和VGG不同的是，网络结构上就有很大的改变，在大家为了提升卷积神经网络的性能在不断提升网络深度的时候，大家发现随着网络深度的提升，网络的效果变得越来越差，甚至出现了网络的退化问题，80层的网络比30层的效果还差，深度网络存在的梯度消失和爆炸问题越来越严重，这使得训练一个优异的深度学习模型变得更加艰难，在这种情况下，网络结构图
何恺明提出了残差神经网络，提出残差学习来解决这个问题，他设计了如下图所示的神经网络结构，并在VGG19的基础上进行了修改。简单来说就是类似与加网络之前的结果，拉出来拉到后面进行拼接，组成新的输出。
事实上在一些目标检测算法例如yolo系列的算法当中也用到了Resnet的结构，而且在很多多尺度特征融合的算法里 也是采用类似的方法，多层不同的输出组合在一起，因此学好Resnet网络对于以后学习目标检测算法具有深刻的意义。
导入库：
import torchimport torchvisionimport torchvision.modelsimport osfrom matplotlib import pyplot as pltfrom tqdm import tqdmfrom torch import nnfrom torch.utils.data import DataLoaderfrom torchvision.transforms import transforms图像预处理：
将图像放缩成120*120进行处理，如果需要放缩成其他比例的，直接修改代码中的120成其他数即可。
data_transform = { "train": transforms.Compose([transforms.RandomResizedCrop(120), transforms.RandomHorizontalFlip(), transforms.ToTensor(), transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))]), "val": transforms.Compose([transforms.Resize((120, 120)), # cannot 224, must (224, 224) transforms.ToTensor(), transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])}导入数据：
将数据像挤牙膏似的一点一点的抽出去，设置相应的batc_size
自己的数据放在跟代码相同的文件夹下新建一个data文件夹，data文件夹里的新建一个train文件夹用于放置训练集的图片。同理新建一个val文件夹用于放置测试集的图片。
train_data = torchvision.datasets.ImageFolder(root = "./data/train" , transform = data_transform["train"])traindata = DataLoader(dataset=train_data, batch_size=128, shuffle=True, num_workers=0) # 将训练数据以每次32张图片的形式抽出进行训练test_data = torchvision.datasets.ImageFolder(root = "./data/val" , transform = data_transform["val"])train_size = len(train_data) # 训练集的长度test_size = len(test_data) # 测试集的长度print(train_size) #输出训练集长度看一下，相当于看看有几张图片print(test_size) #输出测试集长度看一下，相当于看看有几张图片testdata = DataLoader(dataset=test_data, batch_size=128, shuffle=True, num_workers=0) # 将训练数据以每次32张图片的形式抽出进行测试设置GPU 和 CPU的使用：
有GPU则调用GPU，没有的话就调用CPU
device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")print("using {} device.".format(device))构建Resnet网络：
因为Resnet网络太深，所以一般采用迁移学习的方法进行搭建
class BasicBlock(nn.Module): expansion = 1 def __init__(self, in_channel, out_channel, stride=1, downsample=None, **kwargs): super(BasicBlock, self).__init__() self.conv1 = nn.Conv2d(in_channels=in_channel, out_channels=out_channel, kernel_size=3, stride=stride, padding=1, bias=False) self.bn1 = nn.BatchNorm2d(out_channel) self.relu = nn.ReLU() self.conv2 = nn.Conv2d(in_channels=out_channel, out_channels=out_channel, kernel_size=3, stride=1, padding=1, bias=False) self.bn2 = nn.BatchNorm2d(out_channel) self.downsample = downsample def forward(self, x): identity = x if self.downsample is not None: identity = self.downsample(x) out = self.conv1(x) out = self.bn1(out) out = self.relu(out) out = self.conv2(out) out = self.bn2(out) out += identity out = self.relu(out) return outclass Bottleneck(nn.Module): expansion = 4 def __init__(self, in_channel, out_channel, stride=1, downsample=None, groups=1, width_per_group=64): super(Bottleneck, self).__init__() width = int(out_channel * (width_per_group / 64.)) * groups self.conv1 = nn.Conv2d(in_channels=in_channel, out_channels=width, kernel_size=1, stride=1, bias=False) # squeeze channels self.bn1 = nn.BatchNorm2d(width) # ----------------------------------------- self.conv2 = nn.Conv2d(in_channels=width, out_channels=width, groups=groups, kernel_size=3, stride=stride, bias=False, padding=1) self.bn2 = nn.BatchNorm2d(width) # ----------------------------------------- self.conv3 = nn.Conv2d(in_channels=width, out_channels=out_channel*self.expansion, kernel_size=1, stride=1, bias=False) # unsqueeze channels self.bn3 = nn.BatchNorm2d(out_channel*self.expansion) self.relu = nn.ReLU(inplace=True) self.downsample = downsample def forward(self, x): identity = x if self.downsample is not None: identity = self.downsample(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) out += identity out = self.relu(out) return outclass ResNet(nn.Module): def __init__(self, block, blocks_num, num_classes=7,#种类修改的地方，你是几种，就把这个改成几，我是7中所以这里是7 include_top=True, groups=1, width_per_group=64): super(ResNet, self).__init__() self.include_top = include_top self.in_channel = 64 self.groups = groups self.width_per_group = width_per_group self.conv1 = nn.Conv2d(3, self.in_channel, kernel_size=7, stride=2, padding=3, bias=False) self.bn1 = nn.BatchNorm2d(self.in_channel) self.relu = nn.ReLU(inplace=True) self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1) self.layer1 = self._make_layer(block, 64, blocks_num[0]) self.layer2 = self._make_layer(block, 128, blocks_num[1], stride=2) self.layer3 = self._make_layer(block, 256, blocks_num[2], stride=2) self.layer4 = self._make_layer(block, 512, blocks_num[3], stride=2) if self.include_top: self.avgpool = nn.AdaptiveAvgPool2d((1, 1)) # output size = (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') def _make_layer(self, block, channel, block_num, stride=1): downsample = None if stride != 1 or self.in_channel != channel * block.expansion: downsample = nn.Sequential( nn.Conv2d(self.in_channel, channel * block.expansion, kernel_size=1, stride=stride, bias=False), nn.BatchNorm2d(channel * block.expansion)) layers = [] layers.append(block(self.in_channel, channel, downsample=downsample, stride=stride, groups=self.groups, width_per_group=self.width_per_group)) self.in_channel = channel * block.expansion for _ in range(1, block_num): layers.append(block(self.in_channel, channel, groups=self.groups, width_per_group=self.width_per_group)) return nn.Sequential(*layers) def forward(self, x): x = self.conv1(x) x = self.bn1(x) x = self.relu(x) x = self.maxpool(x) x = self.layer1(x) x = self.layer2(x) x = self.layer3(x) x = self.layer4(x) if self.include_top: x = self.avgpool(x) x = torch.flatten(x, 1) x = self.fc(x) return xdef resnet34(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet34-333f7ec4.pth return ResNet(BasicBlock, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top)def resnet50(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet50-19c8e357.pth return ResNet(Bottleneck, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top)def resnet101(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet101-5d3b4d8f.pth return ResNet(Bottleneck, [3, 4, 23, 3], num_classes=num_classes, include_top=include_top)def resnext50_32x4d(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnext50_32x4d-7cdf4587.pth groups = 32 width_per_group = 4 return ResNet(Bottleneck, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top, groups=groups, width_per_group=width_per_group)def resnext101_32x8d(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnext101_32x8d-8ba56ff5.pth groups = 32 width_per_group = 8 return ResNet(Bottleneck, [3, 4, 23, 3], num_classes=num_classes, include_top=include_top, groups=groups, width_per_group=width_per_group)net = resnet34()# load pretrain weights# download url: https://download.pytorch.org/models/resnet34-333f7ec4.pthmodel_weight_path = "./resnet34-pre.pth" #加载resnet的预训练模型assert os.path.exists(model_weight_path), "file {} does not exist.".format(model_weight_path)net.load_state_dict(torch.load(model_weight_path, map_location=device))net.to(device)print(net.to(device)) #输出模型结构启动模型，测试模型输出：
test1 = torch.ones(64, 3, 120, 120) # 测试一下输出的形状大小 输入一个64,3,120,120的向量test1 = net(test1.to(device)) #将向量打入神经网络进行测试print(test1.shape) #查看输出的结果设置训练需要的参数，epoch，学习率learning 优化器。损失函数。
epoch = 10 # 迭代次数即训练次数learning = 0.001 # 学习率optimizer = torch.optim.Adam(net.parameters(), lr=learning) # 使用Adam优化器-写论文的话可以具体查一下这个优化器的原理loss = nn.CrossEntropyLoss() # 损失计算方式，交叉熵损失函数设置四个空数组，用来存放训练集的loss和accuracy 测试集的loss和 accuracy
train_loss_all = []train_accur_all = []test_loss_all = []test_accur_all = []开始训练：
for i in range(epoch): #开始迭代 train_loss = 0 #训练集的损失初始设为0 train_num = 0.0 # train_accuracy = 0.0 #训练集的准确率初始设为0 net.train() #将模型设置成 训练模式 train_bar = tqdm(traindata) #用于进度条显示，没啥实际用处 for step, data in enumerate(train_bar): #开始迭代跑， enumerate这个函数不懂可以查查，将训练集分为 data是序号，data是数据 img, target = data #将data 分位 img图片，target标签 optimizer.zero_grad() # 清空历史梯度 outputs = net(img.to(device)) # 将图片打入网络进行训练,outputs是输出的结果 loss1 = loss(outputs, target.to(device)) # 计算神经网络输出的结果outputs与图片真实标签target的差别-这就是我们通常情况下称为的损失 outputs = torch.argmax(outputs, 1) #会输出10个值，最大的值就是我们预测的结果 求最大值 loss1.backward() #神经网络反向传播 optimizer.step() #梯度优化 用上面的abam优化 train_loss += abs(loss1.item()) * img.size(0) #将所有损失的绝对值加起来 accuracy = torch.sum(outputs == target.to(device)) #outputs == target的 即使预测正确的，统计预测正确的个数,从而计算准确率 train_accuracy = train_accuracy + accuracy #求训练集的准确率 train_num += img.size(0) # print("epoch：{} ， train-Loss：{} , train-accuracy：{}".format(i + 1, train_loss / train_num, #输出训练情况 train_accuracy / train_num)) train_loss_all.append(train_loss / train_num) #将训练的损失放到一个列表里 方便后续画图 train_accur_all.append(train_accuracy.double().item() / train_num)#训练集的准确率开始测试：
test_loss = 0 #同上 测试损失 test_accuracy = 0.0 #测试准确率 test_num = 0 net.eval() #将模型调整为测试模型 with torch.no_grad(): #清空历史梯度，进行测试 与训练最大的区别是测试过程中取消了反向传播 test_bar = tqdm(testdata) for data in test_bar: img, target = data outputs = net(img.to(device)) loss2 = loss(outputs, target.to(device)) outputs = torch.argmax(outputs, 1) test_loss = test_loss + abs(loss2.item()) * img.size(0) accuracy = torch.sum(outputs == target.to(device)) test_accuracy = test_accuracy + accuracy test_num += img.size(0) print("test-Loss：{} , test-accuracy：{}".format(test_loss / test_num, test_accuracy / test_num)) test_loss_all.append(test_loss / test_num) test_accur_all.append(test_accuracy.double().item() / test_num)绘制训练集loss和accuracy图 和测试集的loss和accuracy图：
#下面的是画图过程，将上述存放的列表 画出来即可plt.figure(figsize=(12, 4))plt.subplot(1, 2, 1)plt.plot(range(epoch), train_loss_all, "ro-", label="Train loss")plt.plot(range(epoch), test_loss_all, "bs-", label="test loss")plt.legend()plt.xlabel("epoch")plt.ylabel("Loss")plt.subplot(1, 2, 2)plt.plot(range(epoch), train_accur_all, "ro-", label="Train accur")plt.plot(range(epoch), test_accur_all, "bs-", label="test accur")plt.xlabel("epoch")plt.ylabel("acc")plt.legend()plt.show()torch.save(net.state_dict(), "Resnet.pth")print("模型已保存")全部train训练代码：
import torchimport torchvisionimport torchvision.modelsimport osfrom matplotlib import pyplot as pltfrom tqdm import tqdmfrom torch import nnfrom torch.utils.data import DataLoaderfrom torchvision.transforms import transformsfrom sklearn.metrics import accuracy_score, confusion_matrix, classification_reportdata_transform = { "train": transforms.Compose([transforms.RandomResizedCrop(120), transforms.RandomHorizontalFlip(), transforms.ToTensor(), transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))]), "val": transforms.Compose([transforms.Resize((120, 120)), # cannot 224, must (224, 224) transforms.ToTensor(), transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])}train_data = torchvision.datasets.ImageFolder(root = "./data/train" , transform = data_transform["train"])traindata = DataLoader(dataset=train_data, batch_size=128, shuffle=True, num_workers=0) # 将训练数据以每次32张图片的形式抽出进行训练test_data = torchvision.datasets.ImageFolder(root = "./data/val" , transform = data_transform["val"])train_size = len(train_data) # 训练集的长度test_size = len(test_data) # 测试集的长度print(train_size) #输出训练集长度看一下，相当于看看有几张图片print(test_size) #输出测试集长度看一下，相当于看看有几张图片testdata = DataLoader(dataset=test_data, batch_size=128, shuffle=True, num_workers=0) # 将训练数据以每次32张图片的形式抽出进行测试device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")print("using {} device.".format(device))class BasicBlock(nn.Module): expansion = 1 def __init__(self, in_channel, out_channel, stride=1, downsample=None, **kwargs): super(BasicBlock, self).__init__() self.conv1 = nn.Conv2d(in_channels=in_channel, out_channels=out_channel, kernel_size=3, stride=stride, padding=1, bias=False) self.bn1 = nn.BatchNorm2d(out_channel) self.relu = nn.ReLU() self.conv2 = nn.Conv2d(in_channels=out_channel, out_channels=out_channel, kernel_size=3, stride=1, padding=1, bias=False) self.bn2 = nn.BatchNorm2d(out_channel) self.downsample = downsample def forward(self, x): identity = x if self.downsample is not None: identity = self.downsample(x) out = self.conv1(x) out = self.bn1(out) out = self.relu(out) out = self.conv2(out) out = self.bn2(out) out += identity out = self.relu(out) return outclass Bottleneck(nn.Module): expansion = 4 def __init__(self, in_channel, out_channel, stride=1, downsample=None, groups=1, width_per_group=64): super(Bottleneck, self).__init__() width = int(out_channel * (width_per_group / 64.)) * groups self.conv1 = nn.Conv2d(in_channels=in_channel, out_channels=width, kernel_size=1, stride=1, bias=False) # squeeze channels self.bn1 = nn.BatchNorm2d(width) # ----------------------------------------- self.conv2 = nn.Conv2d(in_channels=width, out_channels=width, groups=groups, kernel_size=3, stride=stride, bias=False, padding=1) self.bn2 = nn.BatchNorm2d(width) # ----------------------------------------- self.conv3 = nn.Conv2d(in_channels=width, out_channels=out_channel*self.expansion, kernel_size=1, stride=1, bias=False) # unsqueeze channels self.bn3 = nn.BatchNorm2d(out_channel*self.expansion) self.relu = nn.ReLU(inplace=True) self.downsample = downsample def forward(self, x): identity = x if self.downsample is not None: identity = self.downsample(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) out += identity out = self.relu(out) return outclass ResNet(nn.Module): def __init__(self, block, blocks_num, num_classes=7, include_top=True, groups=1, width_per_group=64): super(ResNet, self).__init__() self.include_top = include_top self.in_channel = 64 self.groups = groups self.width_per_group = width_per_group self.conv1 = nn.Conv2d(3, self.in_channel, kernel_size=7, stride=2, padding=3, bias=False) self.bn1 = nn.BatchNorm2d(self.in_channel) self.relu = nn.ReLU(inplace=True) self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1) self.layer1 = self._make_layer(block, 64, blocks_num[0]) self.layer2 = self._make_layer(block, 128, blocks_num[1], stride=2) self.layer3 = self._make_layer(block, 256, blocks_num[2], stride=2) self.layer4 = self._make_layer(block, 512, blocks_num[3], stride=2) if self.include_top: self.avgpool = nn.AdaptiveAvgPool2d((1, 1)) # output size = (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') def _make_layer(self, block, channel, block_num, stride=1): downsample = None if stride != 1 or self.in_channel != channel * block.expansion: downsample = nn.Sequential( nn.Conv2d(self.in_channel, channel * block.expansion, kernel_size=1, stride=stride, bias=False), nn.BatchNorm2d(channel * block.expansion)) layers = [] layers.append(block(self.in_channel, channel, downsample=downsample, stride=stride, groups=self.groups, width_per_group=self.width_per_group)) self.in_channel = channel * block.expansion for _ in range(1, block_num): layers.append(block(self.in_channel, channel, groups=self.groups, width_per_group=self.width_per_group)) return nn.Sequential(*layers) def forward(self, x): x = self.conv1(x) x = self.bn1(x) x = self.relu(x) x = self.maxpool(x) x = self.layer1(x) x = self.layer2(x) x = self.layer3(x) x = self.layer4(x) if self.include_top: x = self.avgpool(x) x = torch.flatten(x, 1) x = self.fc(x) return xdef resnet34(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet34-333f7ec4.pth return ResNet(BasicBlock, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top)def resnet50(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet50-19c8e357.pth return ResNet(Bottleneck, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top)def resnet101(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet101-5d3b4d8f.pth return ResNet(Bottleneck, [3, 4, 23, 3], num_classes=num_classes, include_top=include_top)def resnext50_32x4d(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnext50_32x4d-7cdf4587.pth groups = 32 width_per_group = 4 return ResNet(Bottleneck, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top, groups=groups, width_per_group=width_per_group)def resnext101_32x8d(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnext101_32x8d-8ba56ff5.pth groups = 32 width_per_group = 8 return ResNet(Bottleneck, [3, 4, 23, 3], num_classes=num_classes, include_top=include_top, groups=groups, width_per_group=width_per_group)net = resnet34()# load pretrain weights# download url: https://download.pytorch.org/models/resnet34-333f7ec4.pthmodel_weight_path = "./resnet34-pre.pth"assert os.path.exists(model_weight_path), "file {} does not exist.".format(model_weight_path)net.load_state_dict(torch.load(model_weight_path, map_location=device))net.to(device)print(net.to(device)) #输出模型结构test1 = torch.ones(64, 3, 120, 120) # 测试一下输出的形状大小 输入一个64,3,120,120的向量test1 = net(test1.to(device)) #将向量打入神经网络进行测试print(test1.shape) #查看输出的结果epoch = 10 # 迭代次数即训练次数learning = 0.001 # 学习率optimizer = torch.optim.Adam(net.parameters(), lr=learning) # 使用Adam优化器-写论文的话可以具体查一下这个优化器的原理loss = nn.CrossEntropyLoss() # 损失计算方式，交叉熵损失函数train_loss_all = [] # 存放训练集损失的数组train_accur_all = [] # 存放训练集准确率的数组test_loss_all = [] # 存放测试集损失的数组test_accur_all = [] # 存放测试集准确率的数组for i in range(epoch): #开始迭代 train_loss = 0 #训练集的损失初始设为0 train_num = 0.0 # train_accuracy = 0.0 #训练集的准确率初始设为0 net.train() #将模型设置成 训练模式 train_bar = tqdm(traindata) #用于进度条显示，没啥实际用处 for step, data in enumerate(train_bar): #开始迭代跑， enumerate这个函数不懂可以查查，将训练集分为 data是序号，data是数据 img, target = data #将data 分位 img图片，target标签 optimizer.zero_grad() # 清空历史梯度 outputs = net(img.to(device)) # 将图片打入网络进行训练,outputs是输出的结果 loss1 = loss(outputs, target.to(device)) # 计算神经网络输出的结果outputs与图片真实标签target的差别-这就是我们通常情况下称为的损失 outputs = torch.argmax(outputs, 1) #会输出10个值，最大的值就是我们预测的结果 求最大值 loss1.backward() #神经网络反向传播 optimizer.step() #梯度优化 用上面的abam优化 train_loss += abs(loss1.item()) * img.size(0) #将所有损失的绝对值加起来 accuracy = torch.sum(outputs == target.to(device)) #outputs == target的 即使预测正确的，统计预测正确的个数,从而计算准确率 train_accuracy = train_accuracy + accuracy #求训练集的准确率 train_num += img.size(0) # print("epoch：{} ， train-Loss：{} , train-accuracy：{}".format(i + 1, train_loss / train_num, #输出训练情况 train_accuracy / train_num)) train_loss_all.append(train_loss / train_num) #将训练的损失放到一个列表里 方便后续画图 train_accur_all.append(train_accuracy.double().item() / train_num)#训练集的准确率 test_loss = 0 #同上 测试损失 test_accuracy = 0.0 #测试准确率 test_num = 0 net.eval() #将模型调整为测试模型 with torch.no_grad(): #清空历史梯度，进行测试 与训练最大的区别是测试过程中取消了反向传播 test_bar = tqdm(testdata) for data in test_bar: img, target = data outputs = net(img.to(device)) loss2 = loss(outputs, target.to(device)) outputs = torch.argmax(outputs, 1) test_loss = test_loss + abs(loss2.item()) * img.size(0) accuracy = torch.sum(outputs == target.to(device)) test_accuracy = test_accuracy + accuracy test_num += img.size(0) print("test-Loss：{} , test-accuracy：{}".format(test_loss / test_num, test_accuracy / test_num)) test_loss_all.append(test_loss / test_num) test_accur_all.append(test_accuracy.double().item() / test_num)#下面的是画图过程，将上述存放的列表 画出来即可plt.figure(figsize=(12, 4))plt.subplot(1, 2, 1)plt.plot(range(epoch), train_loss_all, "ro-", label="Train loss")plt.plot(range(epoch), test_loss_all, "bs-", label="test loss")plt.legend()plt.xlabel("epoch")plt.ylabel("Loss")plt.subplot(1, 2, 2)plt.plot(range(epoch), train_accur_all, "ro-", label="Train accur")plt.plot(range(epoch), test_accur_all, "bs-", label="test accur")plt.xlabel("epoch")plt.ylabel("acc")plt.legend()plt.show()torch.save(net.state_dict(), "Resnet.pth")print("模型已保存")全部predict代码：
import torchfrom PIL import Imagefrom torch import nnfrom torchvision.transforms import transformsimage_path = "1.JPG" # 相对路径 导入图片trans = transforms.Compose([transforms.Resize((120, 120)), transforms.ToTensor()]) # 将图片缩放为跟训练集图片的大小一样 方便预测，且将图片转换为张量image = Image.open(image_path) # 打开图片print(image) # 输出图片 看看图片格式image = image.convert("RGB") # 将图片转换为RGB格式image = trans(image) # 上述的缩放和转张量操作在这里实现print(image) # 查看转换后的样子image = torch.unsqueeze(image, dim=0) # 将图片维度扩展一维classes = ["1", "2", "3", "4", "5", "6", "7"] # 预测种类#自己是几种，这里就改成自己种类的字符数组class BasicBlock(nn.Module): expansion = 1 def __init__(self, in_channel, out_channel, stride=1, downsample=None, **kwargs): super(BasicBlock, self).__init__() self.conv1 = nn.Conv2d(in_channels=in_channel, out_channels=out_channel, kernel_size=3, stride=stride, padding=1, bias=False) self.bn1 = nn.BatchNorm2d(out_channel) self.relu = nn.ReLU() self.conv2 = nn.Conv2d(in_channels=out_channel, out_channels=out_channel, kernel_size=3, stride=1, padding=1, bias=False) self.bn2 = nn.BatchNorm2d(out_channel) self.downsample = downsample def forward(self, x): identity = x if self.downsample is not None: identity = self.downsample(x) out = self.conv1(x) out = self.bn1(out) out = self.relu(out) out = self.conv2(out) out = self.bn2(out) out += identity out = self.relu(out) return outclass Bottleneck(nn.Module): """ 注意：原论文中，在虚线残差结构的主分支上，第一个1x1卷积层的步距是2，第二个3x3卷积层步距是1。 但在pytorch官方实现过程中是第一个1x1卷积层的步距是1，第二个3x3卷积层步距是2， 这么做的好处是能够在top1上提升大概0.5%的准确率。 可参考Resnet v1.5 https://ngc.nvidia.com/catalog/model-scripts/nvidia:resnet_50_v1_5_for_pytorch """ expansion = 4 def __init__(self, in_channel, out_channel, stride=1, downsample=None, groups=1, width_per_group=64): super(Bottleneck, self).__init__() width = int(out_channel * (width_per_group / 64.)) * groups self.conv1 = nn.Conv2d(in_channels=in_channel, out_channels=width, kernel_size=1, stride=1, bias=False) # squeeze channels self.bn1 = nn.BatchNorm2d(width) # ----------------------------------------- self.conv2 = nn.Conv2d(in_channels=width, out_channels=width, groups=groups, kernel_size=3, stride=stride, bias=False, padding=1) self.bn2 = nn.BatchNorm2d(width) # ----------------------------------------- self.conv3 = nn.Conv2d(in_channels=width, out_channels=out_channel*self.expansion, kernel_size=1, stride=1, bias=False) # unsqueeze channels self.bn3 = nn.BatchNorm2d(out_channel*self.expansion) self.relu = nn.ReLU(inplace=True) self.downsample = downsample def forward(self, x): identity = x if self.downsample is not None: identity = self.downsample(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) out += identity out = self.relu(out) return outclass ResNet(nn.Module): def __init__(self, block, blocks_num, num_classes=7, include_top=True, groups=1, width_per_group=64): super(ResNet, self).__init__() self.include_top = include_top self.in_channel = 64 self.groups = groups self.width_per_group = width_per_group self.conv1 = nn.Conv2d(3, self.in_channel, kernel_size=7, stride=2, padding=3, bias=False) self.bn1 = nn.BatchNorm2d(self.in_channel) self.relu = nn.ReLU(inplace=True) self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1) self.layer1 = self._make_layer(block, 64, blocks_num[0]) self.layer2 = self._make_layer(block, 128, blocks_num[1], stride=2) self.layer3 = self._make_layer(block, 256, blocks_num[2], stride=2) self.layer4 = self._make_layer(block, 512, blocks_num[3], stride=2) if self.include_top: self.avgpool = nn.AdaptiveAvgPool2d((1, 1)) # output size = (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') def _make_layer(self, block, channel, block_num, stride=1): downsample = None if stride != 1 or self.in_channel != channel * block.expansion: downsample = nn.Sequential( nn.Conv2d(self.in_channel, channel * block.expansion, kernel_size=1, stride=stride, bias=False), nn.BatchNorm2d(channel * block.expansion)) layers = [] layers.append(block(self.in_channel, channel, downsample=downsample, stride=stride, groups=self.groups, width_per_group=self.width_per_group)) self.in_channel = channel * block.expansion for _ in range(1, block_num): layers.append(block(self.in_channel, channel, groups=self.groups, width_per_group=self.width_per_group)) return nn.Sequential(*layers) def forward(self, x): x = self.conv1(x) x = self.bn1(x) x = self.relu(x) x = self.maxpool(x) x = self.layer1(x) x = self.layer2(x) x = self.layer3(x) x = self.layer4(x) if self.include_top: x = self.avgpool(x) x = torch.flatten(x, 1) x = self.fc(x) return xdef resnet34(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet34-333f7ec4.pth return ResNet(BasicBlock, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top)def resnet50(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet50-19c8e357.pth return ResNet(Bottleneck, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top)def resnet101(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnet101-5d3b4d8f.pth return ResNet(Bottleneck, [3, 4, 23, 3], num_classes=num_classes, include_top=include_top)def resnext50_32x4d(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnext50_32x4d-7cdf4587.pth groups = 32 width_per_group = 4 return ResNet(Bottleneck, [3, 4, 6, 3], num_classes=num_classes, include_top=include_top, groups=groups, width_per_group=width_per_group)def resnext101_32x8d(num_classes=1000, include_top=True): # https://download.pytorch.org/models/resnext101_32x8d-8ba56ff5.pth groups = 32 width_per_group = 8 return ResNet(Bottleneck, [3, 4, 23, 3], num_classes=num_classes, include_top=include_top, groups=groups, width_per_group=width_per_group)# 以上是神经网络结构，因为读取了模型之后代码还得知道神经网络的结构才能进行预测device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu") # 将代码放入GPU进行训练print("using {} device.".format(device))net = resnet34()net.load_state_dict(torch.load("Resnet.pth", map_location=device))net.to(device)net.eval() # 关闭梯度，将模型调整为测试模式with torch.no_grad(): # 梯度清零 outputs = net(image.to(device)) # 将图片打入神经网络进行测试 print(net) # 输出模型结构 print(outputs) # 输出预测的张量数组 ans = (outputs.argmax(1)).item() # 最大的值即为预测结果，找出最大值在数组中的序号， # 对应找其在种类中的序号即可然后输出即为其种类 print(classes[ans])##输出的是那种即为预测结果代码下载链接：链接：https://pan.baidu.com/s/1el2kss9x1qiSLd4B4H3Iyw
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