Class: SquaredL2Updater

Class used to perform steps (weight update) using Gradient Descent methods. For general minimization problems, or for regularized problems of the form min L(w) + regParam * R(w), the compute function performs the actual update step, when given some (e.g. stochastic) gradient direction for the loss L(w), and a desired step-size (learning rate).The updater is responsible to also perform the update coming from the regularization term R(w) (if any regularization is used).