TensorBoard

• 代码案例：

  from torch.utils.tensorboard import SummaryWriter
  import torch
  import torchvision
  from torchvision import datasets, transforms# 设置TensorBoard日志路径
  writer = SummaryWriter('runs/mnist')# 加载数据集
  transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.5,), (0.5,))])
  trainset = datasets.MNIST('~/.pytorch/MNIST_data/', download=True, train=True, transform=transform)
  trainloader = torch.utils.data.DataLoader(trainset, batch_size=64, shuffle=True)# 添加图像到TensorBoard
  images, labels = next(iter(trainloader))
  img_grid = torchvision.utils.make_grid(images)
  writer.add_image('mnist_images', img_grid)
  writer.close()
  

  此代码展示了如何使用TensorBoard记录和可视化图像数据。

t-SNE降维可视化

• 代码案例：

  from sklearn.manifold import TSNE
  from sklearn.datasets import load_iris
  import matplotlib.pyplot as plt# 加载数据
  iris = load_iris()
  X = iris.data
  y = iris.target# t-SNE降维
  tsne = TSNE(n_components=2, random_state=42)
  X_tsne = tsne.fit_transform(X)# 可视化
  plt.figure(figsize=(8, 8))
  colors = ['red', 'green', 'blue']
  for i in range(len(colors)):plt.scatter(X_tsne[y == i, 0], X_tsne[y == i, 1], c=colors[i], label=iris.target_names[i])
  plt.legend()
  plt.show()
  

  此代码使用t-SNE将鸢尾花数据集从4维降至2维，并进行可视化。

特征图可视化

• 代码案例：

  import torch
  import torchvision.models as models
  import torchvision.transforms as transforms
  from PIL import Image
  import matplotlib.pyplot as plt# 加载预训练模型
  model = models.resnet18(pretrained=True)
  model.eval()# 加载图像
  img = Image.open('path_to_image.jpg')
  transform = transforms.Compose([transforms.Resize(256),transforms.CenterCrop(224),transforms.ToTensor(),transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])])
  img = transform(img).unsqueeze(0)# 获取特征图
  with torch.no_grad():features = model.conv1(img)features = features.squeeze(0)# 可视化特征图
  fig, ax = plt.subplots(1, 3, figsize=(15, 5))
  for i in range(3):ax[i].imshow(features[i].cpu().numpy(), cmap='viridis')ax[i].axis('off')
  plt.show()
  

  此代码展示了如何提取并可视化ResNet模型中的特征图。

混淆矩阵和ROC曲线可视化

• 代码案例：

  from sklearn.metrics import confusion_matrix, ConfusionMatrixDisplay, roc_curve, auc
  import matplotlib.pyplot as plt# 假设y_true是真实标签，y_pred是预测标签，y_scores是预测概率
  y_true = [0, 1, 0, 1, 0, 1, 0, 1]
  y_pred = [0, 0, 0, 1, 0, 1, 1, 1]
  y_scores = [0.1, 0.4, 0.35, 0.8, 0.2, 0.7, 0.6, 0.9]# 绘制混淆矩阵
  cm = confusion_matrix(y_true, y_pred)
  disp = ConfusionMatrixDisplay(confusion_matrix=cm)
  disp.plot(cmap=plt.cm.Blues)
  plt.title('Confusion Matrix')
  plt.show()# 绘制ROC曲线
  fpr, tpr, _ = roc_curve(y_true, y_scores)
  roc_auc = auc(fpr, tpr)
  plt.plot(fpr, tpr, color='blue', lw=2, label='ROC curve (area = %0.2f)' % roc_auc)
  plt.plot([0, 1], [0, 1], color='gray', linestyle='--')
  plt.title('Receiver Operating Characteristic (ROC) Curve')
  plt.xlabel('False Positive Rate')
  plt.ylabel('True Positive Rate')
  plt.legend(loc='lower right')
  plt.show()
  

  此代码展示了如何绘制混淆矩阵和ROC曲线。

Neptune团队协作

• 代码案例：

  import neptune.new as neptune
  from sklearn.model_selection import train_test_split
  from sklearn.linear_model import LogisticRegression
  from sklearn.metrics import accuracy_score# 初始化Neptune项目
  run = neptune.init_run(project="your_project_name", api_token="your_api_token")# 记录实验参数
  params = {"n_estimators": 100, "learning_rate": 0.1}
  run["parameters"] = params# 加载数据
  X, y = load_data()
  X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)# 训练模型
  model = LogisticRegression()
  model.fit(X_train, y_train)
  y_pred = model.predict(X_test)
  accuracy = accuracy_score(y_test, y_pred)# 记录模型性能
  run["accuracy"] = accuracy# 保存模型
  run["model"].upload("model.pkl")# 结束实验
  run.stop()
  

  此代码展示了如何使用Neptune记录实验参数、模型性能和模型文件。

WandB

• 代码案例：

  import wandb
  import torch
  import torch.nn as nn
  import torch.optim as optim
  from torch.utils.data import DataLoader
  from torchvision import datasets, transforms# 初始化WandB项目
  wandb.init(project="your_project_name")# 加载数据集
  transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.5,), (0.5,))])
  trainset = datasets.MNIST('~/.pytorch/MNIST_data/', download=True, train=True, transform=transform)
  trainloader = DataLoader(trainset, batch_size=64, shuffle=True)# 定义模型
  model = nn.Sequential(nn.Linear(784, 128),nn.ReLU(),nn.Linear(128, 64),nn.ReLU(),nn.Linear(64, 10),nn.LogSoftmax(dim=1))
  criterion = nn.NLLLoss()
  optimizer = optim.SGD(model.parameters(), lr=0.003)# 训练模型
  epochs = 5
  for epoch in range(epochs):running_loss = 0for images, labels in trainloader:images = images.view(images.shape[0], -1)optimizer.zero_grad()output = model(images)loss = criterion(output, labels)loss.backward()optimizer.step()running_loss += loss.item()wandb.log({"loss": running_loss / len(trainloader)})print(f"Epoch {epoch+1}/{epochs}, Loss: {running_loss / len(trainloader)}")# 结束WandB实验
  wandb.finish()
  

  此代码展示了如何使用WandB记录训练过程中的损失。

VisualDL（PaddlePaddle）

• 代码案例：

  import paddle
  from paddle.vision.models import resnet18
  from paddle.vision.datasets import Cifar10
  from paddle.vision.transforms import Compose, Normalize
  from visualdl import LogWriter# 初始化VisualDL日志
  log_writer = LogWriter("log")# 加载数据集
  transform = Compose([Normalize(mean=[127.5, 127.5, 127.5], std=[127.5, 127.5, 127.5], data_format='HWC')])
  train_dataset = Cifar10(mode='train', transform=transform)
  train_loader = paddle.io.DataLoader(train_dataset, batch_size=64, shuffle=True)# 定义模型
  model = resnet18(pretrained=True)
  criterion = paddle.nn.CrossEntropyLoss()
  optimizer = paddle.optimizer.Adam(parameters=model.parameters(), learning_rate=0.001)# 训练模型
  epochs = 5
  for epoch in range(epochs):for i, (images, labels) in enumerate(train_loader()):output = model(images)loss = criterion(output, labels)loss.backward()optimizer.step()optimizer.clear_grad()log_writer.add_scalar(tag="loss", step=i + epoch * len(train_loader()), value=loss.numpy())print(f"Epoch {epoch+1}/{epochs}, Loss: {loss.numpy()[0]}")
  

  此代码展示了如何使用VisualDL记录PaddlePaddle模型训练过程中的损失。

高维特征降维可视化（PCA）

• 代码案例：

  from sklearn.decomposition import PCA
  from sklearn.datasets import load_iris
  import matplotlib.pyplot as plt# 加载数据
  iris = load_iris()
  X = iris.data
  y = iris.target# PCA降维
  pca = PCA(n_components=2)
  X_pca = pca.fit_transform(X)# 可视化
  plt.figure(figsize=(8, 8))
  colors = ['red', 'green', 'blue']
  for i in range(len(colors)):plt.scatter(X_pca[y == i, 0], X_pca[y == i, 1], c=colors[i], label=iris.target_names[i])
  plt.legend()
  plt.show()
  

  此代码使用PCA将鸢尾花数据集从4维降至2维，并进行可视化。

特征图可视化（卷积层）

• 代码案例：

  import torch
  import torch.nn as nn
  import torchvision.models as models
  import torchvision.transforms as transforms
  from PIL import Image
  import matplotlib.pyplot as plt# 加载预训练模型
  model = models.resnet18(pretrained=True)
  model.eval()# 加载图像
  img = Image.open('path_to_image.jpg')
  transform = transforms.Compose([transforms.Resize(256),transforms.CenterCrop(224),transforms.ToTensor(),transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
  ])
  img = transform(img).unsqueeze(0)# 获取特征图
  with torch.no_grad():features = model.conv1(img)features = features.squeeze(0)# 可视化特征图
  fig, ax = plt.subplots(1, 3, figsize=(15, 5))
  for i in range(3):ax[i].imshow(features[i].cpu().numpy(), cmap='viridis')ax[i].axis('off')
  plt.show()
  

  此代码展示了如何提取并可视化ResNet模型中的特征图。通过选择不同的卷积层（如model.layer1、model.layer2等），可以进一步探索模型在不同层次提取的特征。

Grad-CAM 可视化

• 代码案例：

  import cv2
  import numpy as np
  import torch
  import torch.nn as nn
  import torchvision.models as models
  import torchvision.transforms as transforms
  from PIL import Image
  import matplotlib.pyplot as plt# 加载预训练模型
  model = models.resnet18(pretrained=True)
  model.eval()# 加载图像
  img = Image.open('path_to_image.jpg')
  transform = transforms.Compose([transforms.Resize(256),transforms.CenterCrop(224),transforms.ToTensor(),transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
  ])
  img_tensor = transform(img).unsqueeze(0)# 获取模型的最后一个卷积层的输出
  def get_last_conv_layer(model):for name, module in model.named_modules():if isinstance(module, nn.Conv2d):last_conv_layer = modulereturn last_conv_layerlast_conv_layer = get_last_conv_layer(model)# 前向传播
  outputs = []
  def hook(module, input, output):outputs.append(output)
  handle = last_conv_layer.register_forward_hook(hook)with torch.no_grad():output = model(img_tensor)handle.remove()# 获取特征图和类别权重
  feature_map = outputs[0].squeeze(0).cpu().numpy()
  weights = model.fc.weight.data.cpu().numpy()# 计算 Grad-CAM
  class_idx = torch.argmax(output).item()
  cam = np.zeros(feature_map.shape[1:], dtype=np.float32)
  for i, w in enumerate(weights[class_idx]):cam += w * feature_map[i, :, :]cam = cv2.resize(cam, (224, 224))
  cam = np.maximum(cam, 0)
  cam = cam / np.max(cam)# 可视化
  img = cv2.imread('path_to_image.jpg')
  img = cv2.resize(img, (224, 224))
  heatmap = cv2.applyColorMap(np.uint8(255 * cam), cv2.COLORMAP_JET)
  heatmap = cv2.cvtColor(heatmap, cv2.COLOR_BGR2RGB)
  superimposed_img = heatmap * 0.4 + img * 0.6plt.imshow(superimposed_img.astype(np.uint8))
  plt.axis('off')
  plt.show()
  

  此代码通过 Grad-CAM 生成热力图，可视化模型对输入图像的注意力区域。

混淆矩阵和 ROC 曲线可视化

• 代码案例：

  from sklearn.metrics import confusion_matrix, ConfusionMatrixDisplay, roc_curve, auc
  import matplotlib.pyplot as plt# 假设 y_true 是真实标签，y_pred 是预测标签，y_scores 是预测概率
  y_true = [0, 1, 0, 1, 0, 1, 0, 1]
  y_pred = [0, 0, 0, 1, 0, 1, 1, 1]
  y_scores = [0.1, 0.4, 0.35, 0.8, 0.2, 0.7, 0.6, 0.9]# 绘制混淆矩阵
  cm = confusion_matrix(y_true, y_pred)
  disp = ConfusionMatrixDisplay(confusion_matrix=cm)
  disp.plot(cmap=plt.cm.Blues)
  plt.title('Confusion Matrix')
  plt.show()# 绘制 ROC 曲线
  fpr, tpr, _ = roc_curve(y_true, y_scores)
  roc_auc = auc(fpr, tpr)
  plt.plot(fpr, tpr, color='blue', lw=2, label='ROC curve (area = %0.2f)' % roc_auc)
  plt.plot([0, 1], [0, 1], color='gray', linestyle='--')
  plt.title('Receiver Operating Characteristic (ROC) Curve')
  plt.xlabel('False Positive Rate')
  plt.ylabel('True Positive Rate')
  plt.legend(loc='lower right')
  plt.show()
  

  此代码展示了如何绘制混淆矩阵和 ROC 曲线，用于评估分类模型的性能。