Logistic回归代价函数的数学推导及实现
logistic回归的代价函数形式如下： J(θ)=−1m[∑i=1my(i)loghθ(x(i))+(1−y(i))log(1−hθ(x(i)))]J(\theta) = -\frac{1}{m}\left[\sum_{i=1}^{m}y^{(i)}\log h_\theta(x^{(i)}) + (1 - y^{(i)})\log (1 - h_\theta(x^{(i)}))\right]可
