An Effective Dynamic Gradient Calibration Method for Continual Learning

TL;DR

This paper introduces a dynamic gradient calibration method for continual learning that aims to mitigate catastrophic forgetting by adjusting gradients during training, inspired by variance reduction techniques, and can enhance existing methods.

Contribution

The paper proposes a novel gradient calibration algorithm for continual learning, inspired by variance reduction, that improves performance and can be integrated with existing methods.

Findings

Improved performance on benchmark datasets

Effective reduction of catastrophic forgetting

Compatible with multiple existing CL methods

Abstract

Continual learning (CL) is a fundamental topic in machine learning, where the goal is to train a model with continuously incoming data and tasks. Due to the memory limit, we cannot store all the historical data, and therefore confront the ``catastrophic forgetting'' problem, i.e., the performance on the previous tasks can substantially decrease because of the missing information in the latter period. Though a number of elegant methods have been proposed, the catastrophic forgetting phenomenon still cannot be well avoided in practice. In this paper, we study the problem from the gradient perspective, where our aim is to develop an effective algorithm to calibrate the gradient in each updating step of the model; namely, our goal is to guide the model to be updated in the right direction under the situation that a large amount of historical data are unavailable. Our idea is partly inspired by the seminal stochastic variance reduction methods (e.g., SVRG and SAGA) for reducing the variance of gradient estimation in stochastic gradient descent algorithms. Another benefit is that our approach can be used as a general tool, which is able to be incorporated with several existing popular CL methods to achieve better performance. We also conduct a set of experiments on several benchmark datasets to evaluate the performance in practice.