简易dropout代码 2026.7.9

import numpy as np class Dropout: def __init__(self, dropout_rate0.5): self.drop_rate dropout_rate self.mask None def forward(self, x, is_trainTrue): if is_train: # x必须是numpy数组才有shape random_mat np.random.rand(*x.shape) self.mask random_mat self.drop_rate output x * self.mask return output else: scale 1 - self.drop_rate output x * scale return output def backward(self, upstream_grad): grad_x upstream_grad * self.mask return grad_x # 测试代码 if __name__ __main__: dropout_layer Dropout(dropout_rate0.5) # 正确传入numpy数组不能传纯数字 x_data np.array([10, 20, 30, 40]) # 训练模式前向传播 train_out dropout_layer.forward(x_data, is_trainTrue) print(训练输出, train_out) # 推理模式前向传播 pred_out dropout_layer.forward(x_data, is_trainFalse) print(推理输出, pred_out) # 反向梯度测试 grad dropout_layer.backward(np.array([1,1,1,1])) print(反向梯度, grad)