论文标题
在凸优化方法中利用高级导数
Exploiting higher-order derivatives in convex optimization methods
论文作者
论文摘要
至少自1970年代以来,在凸优化中利用高阶衍生物是众所周知的。在每种迭代中,高阶(也称为张量)方法最小化了目标函数的正则泰勒膨胀,如果相应的高阶导数是lipschitz的连续,则会导致更快的收敛速率。最近,证明了此类方法的一系列较低的迭代复杂性界限,并揭示了较低的复杂性边界之间的差距。此外,由于可以在凸功能的适当正则化的泰勒扩展,因此可以在多项式时间最小化,因此可以实现此类方法。直到最近,提出了一种具有最佳收敛速率$ 1/k^{(3p+1)/2} $的算法,以最大程度地减少Lipschitz $ p $ -th派生的凸功能。对于Lipschitz第三个衍生品的凸功能,这些开发允许提出一种二阶方法,其收敛速率$ 1/k^5 $,该方法比现有二阶方法的$ 1/k^{3.5} $更快。
Exploiting higher-order derivatives in convex optimization is known at least since 1970's. In each iteration higher-order (also called tensor) methods minimize a regularized Taylor expansion of the objective function, which leads to faster convergence rates if the corresponding higher-order derivative is Lipschitz-continuous. Recently a series of lower iteration complexity bounds for such methods were proved, and a gap between upper an lower complexity bounds was revealed. Moreover, it was shown that such methods can be implementable since the appropriately regularized Taylor expansion of a convex function is also convex and, thus, can be minimized in polynomial time. Only very recently an algorithm with optimal convergence rate $1/k^{(3p+1)/2}$ was proposed for minimizing convex functions with Lipschitz $p$-th derivative. For convex functions with Lipschitz third derivative, these developments allowed to propose a second-order method with convergence rate $1/k^5$, which is faster than the rate $1/k^{3.5}$ of existing second-order methods.