Faster stochastic cubic regularized Newton methods with momentum
Cubic regularized Newton (CRN) methods have attracted signiffcant research interest because they offer stronger solution guarantees and lower iteration complexity. With the rise of the big-data era, there is growing interest in developing stochastic cubic regularized Newton (SCRN) methods that do not require exact gradient and Hessian evaluations. In this paper, we propose faster SCRN methods that incorporate gradient estimation with small, controlled errors and Hessian estimation with momentum-based variance reduction. These methods are particularly effective for problems where the gradient can be estimated accurately and at low cost, whereas accurate estimation of the Hessian is expensive. Under mild assumptions, we establish the iteration complexity of our SCRN methods by analyzing the descent of a novel potential sequence. Finally, numerical experiments show that our SCRN methods can achieve comparable performance to deterministic CRN methods and vastly outperform ffrst-order methods in terms of both iteration counts and solution quality.