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我正在尝试实现一个渐变下降算法,这个算法之前用python编写的matlab中有numpy,但是我得到了一组相似但不同的结果.

这是matlab代码

function [theta] = gradientDescentMulti(X, y, theta, alpha, num_iters)

m = length(y);
num_features = size(X,2);
for iter = 1:num_iters;
    temp_theta = theta;
    for i = 1:num_features
        temp_theta(i) = theta(i)-((alpha/m)*(X * theta - y)'*X(:,i));
    end
    theta = temp_theta;
end


end

和我的python版本

def gradient_descent(X,y, alpha, trials):

    m = X.shape[0]
    n = X.shape[1]
    theta = np.zeros((n, 1))

    for i in range(trials):

        temp_theta = theta
        for p in range(n):
            thetaX = np.dot(X, theta)
            tMinY = thetaX-y
            temp_theta[p] = temp_theta[p]-(alpha/m)*np.dot(tMinY.T, X[:,p:p+1])

        theta = temp_theta …