class DBN(object): def __init__(self, sizes): self.sizes = sizes self.num_layers = len(sizes) self.biases = [np.random.randn(y, 1) for y in sizes[1:]] self.weights = [np.random.randn(y, x) / np.sqrt(x) for x, y in zip(sizes[:-1], sizes[1:])] def sigmoid(self, z): return 1.0 / (1.0 + np.exp(-z)) def feedforward(self, a): for b, w in zip(self.biases, self.weights): a = self.sigmoid(np.dot(w, a) + b) return a def predict(self, X): y_pred = np.zeros_like(y_test) for i in range(len(X)): y_pred[i] = np.argmax(self.feedforward(X[i].reshape(-1, 1))) return y_pred def train(self, dbn_training_data, dbn_epochs): pass

这是一个深度置信网络（Deep Belief Network）的类定义，包含了初始化、sigmoid函数、前向传播、预测和训练等方法。其中，sizes参数表示每层神经元的数量，biases和weights分别表示偏置和权重。feedforward方法实现了前向传播，predict方法用于预测，train方法用于训练。具体的训练过程需要在train方法中实现。