写一段用matlab实现的用于回归分析的bp神经网络代码

使用 Matlab 实现的用于回归分析的 BP 神经网络的代码如下： % BP 神经网络参数设置
inputNum = 3;
hiddenNum = 5;
outputNum = 1;
learnRate = 0.1; % 初始化权值
w1 = rand(inputNum, hiddenNum);
b1 = rand(1, hiddenNum);
w2 = rand(hiddenNum, outputNum);
b2 = rand(1, outputNum); % 训练模型
for iter = 1:200
% 前向传播
h = bsxfun(@plus, train_x * w1, b1);
h_sigmoid = 1 ./ (1 + exp(-1 * h));
o = bsxfun(@plus, h_sigmoid * w2, b2);
% 计算损失
loss = sum((train_y - o).^2);
% 反向传播
delta_o = -2 * (train_y - o);
delta_h = delta_o * w2' .* h_sigmoid .* (1 - h_sigmoid);
delta_w2 = h_sigmoid' * delta_o;
delta_b2 = sum(delta_o);
delta_w1 = train_x' * delta_h;
delta_b1 = sum(delta_h);
% 梯度下降迭代
w1 = w1 - learnRate * delta_w1;
b1 = b1 - learnRate * delta_b1;
w2 = w2 - learnRate * delta_w2;
b2 = b2 - learnRate * delta_b2;
end