arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2203.03351math.OC
收藏

二阶最优性的OFFO极小化算法及其复杂性

OFFO minimization algorithms for second-order optimality and their complexity

S. Gratton, Ph. L. Toint

摘要:

提出了一类受Adagrad启发的光滑无约束优化算法,其中目标函数从未被评估,但梯度范数至少像$\calO(1/\sqrt{k+1})$一样快地下降,而二阶最优性测度至少像$\calO(1/(k+1)^{1/3})$一样快地收敛到零。后者的收敛速度收敛速率被证明是本质上是尖锐的,是相同的,已知的更标准的算法(如信赖域或自适应正则化方法)使用函数和导数的评估。文中还介绍了一种相关的“发散步长”方法,其基本上锐的收敛速度收敛速率稍差。最后讨论了如何获得较弱的二阶最优性保证(大大)减少计算成本。

英文摘要:

An Adagrad-inspired class of algorithms for smooth unconstrained optimization is presented in which the objective function is never evaluated and yet the gradient norms decrease at least as fast as $\calO(1/\sqrt{k+1})$ while second-order optimality measures converge to zero at least as fast as $\calO(1/(k+1)^{1/3})$. This latter rate of convergence is shown to be essentially sharp and is identical to that known for more standard algorithms (like trust-region or adaptive-regularization methods) using both function and derivatives' evaluations. A related "divergent stepsize" method is also described, whose essentially sharp rate of convergence is slighly inferior. It is finally discussed how to obtain weaker second-order optimality guarantees at a (much) reduced computional cost.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑