在基本结构上,变分自编码器的代码基本上不会改变。唯一需要修改的是数据集相关的代码部分,包括数据的读入、预处理、批量处理等。以下是使用PyTorch框架实现变分自编码器的代码示例:
import torch
import torch.nn as nn
import torch.nn.functional as F
class VAE(nn.Module):
def __init__(self, input_dim, latent_dim):
super(VAE, self).__init__()
self.input_dim = input_dim
self.latent_dim = latent_dim
# Encode
self.fc1 = nn.Linear(input_dim, 512)
self.fc2_mean = nn.Linear(512, latent_dim)
self.fc2_log_var = nn.Linear(512, latent_dim)
# Decode
self.fc3 = nn.Linear(latent_dim, 512)
self.fc4 = nn.Linear(512, input_dim)
def encode(self, x):
x = F.relu(self.fc1(x))
mean = self.fc2_mean(x)
log_var = self.fc2_log_var(x)
return mean, log_var
def reparameterize(self, mean, log_var):
std = torch.exp(0.5 * log_var)
eps = torch.randn_like(std)
return eps * std + mean
def decode(self, z):
z = F.relu(self.fc3(z))
reconstruction = torch.sigmoid(self.fc4(z))
return reconstruction
def forward(self, x):
mean, log_var = self.encode(x)
z = self.reparameterize(mean, log_var)
reconstruction = self.decode(z)
return reconstruction, mean, log_var
# Load data
train_data = torch.utils.data.DataLoader(
torchvision.datasets.MNIST('./data',
train=True,
download=True,
transform=torchvision.transforms.Compose([
torchvision.transforms.ToTensor()
])),
batch_size=128,
shuffle=True
)
# Train
model = VAE(input_dim=28*28, latent_dim=10)
optimizer = torch.optim.Adam(model.parameters(), lr=1
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