Dynamics of batch training in a perceptron
Early stopping and weight decay are studied in a linear perceptron using a new simplified approach to the dynamics in the thermodynamical limit. The approach is directly deduced from the gradient descent weight update. It allows an exact description of the dynamics of the batch training process. The results are compared with a recent study of early stopping and weight decay based on the equilibrium statistical mechanics approach. It is shown that the equilibrium results for early stopping are good approximations and are exact for weight decay. Furthermore, in the dynamical approach it is possible to determine the necessary number of training steps to fulfil certain termination conditions. It can be shown that asymptotically, i.e. if the number of examples is large, only two batch steps are required to reach the optimal convergence, if the learning rate is optimally chosen.