# Why Expectation and Maximization algorithm not used in Machine Learning while Gradient Descent algorithm used in Machine Learning?

I know that Newton Raphson, Expectation & Maximization, and Gradient Descent are all known to be optimization methods. Somehow, I wonder why Gradient Descent is chosen to be used in most of Machine Learning applications but I never heard that Expectation & Maximization or Newton Raphson algorithms have been applied. Hope to hear some.

• How do you define "Machine learning"? If broadly, then they are all used... if narrowly, not every optimization algorithm is "best" for every type of problem, e.g., Random Forests will use different algorithms than maximum likelihood estimation of the parameters of a t-distribution. – jbowman Dec 31 '19 at 1:47
• Yes, you make sense. Let's say Machine Learning applications such as Linear Regression, Logistic Regression, and Softmax Regression. – Changhee Kang Dec 31 '19 at 1:50