🔥 推荐系统实战项目集（3个分级项目）¶

# 双塔模型
class TwoTowerModel(nn.Module):  # 继承nn.Module定义网络层
    def __init__(self, num_users, num_items, embedding_dim):
        super().__init__()  # super()调用父类方法
        self.user_emb = nn.Embedding(num_users, embedding_dim)
        self.item_emb = nn.Embedding(num_items, embedding_dim)
        self.user_tower = nn.Sequential(nn.Linear(embedding_dim, 64), nn.ReLU(), nn.Linear(64, 32))
        self.item_tower = nn.Sequential(nn.Linear(embedding_dim, 64), nn.ReLU(), nn.Linear(64, 32))

    def forward(self, user_ids, item_ids):
        user_vec = self.user_tower(self.user_emb(user_ids))
        item_vec = self.item_tower(self.item_emb(item_ids))
        return torch.sigmoid((user_vec * item_vec).sum(dim=1))