全連接層
import torch
from torchvision import datasets, transforms
import torch.nn as nn
import torch.optim as optim
from tqdm import tqdm # 用于進度條顯示
import os# 定義數據預處理(標準化+Tensor轉換)
transform = transforms.Compose([transforms.ToTensor(),transforms.Normalize((0.1307,), (0.3081,)) # MNIST的均值和標準差
])# 下載/加載數據集
train_dataset = datasets.MNIST(root='./data', train=True, download=True, transform=transform
)test_dataset = datasets.MNIST(root='./data', train=False, download=True, transform=transform
)# 創建DataLoader
train_loader = torch.utils.data.DataLoader(train_dataset, batch_size=64, shuffle=True)
test_loader = torch.u