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arXiv 2203.02596stat.ME
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针对幂惩罚的改进路径式坐标下降算法

Improved Pathwise Coordinate Descent for Power Penalties

Maryclare Griffin

AI总结:

本文针对非凸的 $\ell_q$ 惩罚回归问题,通过重新参数化使其更适合路径式坐标下降,提出两种改进的路径式算法,并证明它们比冷启动方法更快且更可能获得更优解。

摘要:

路径式坐标下降算法已被用于快速且成功地计算 lasso 及其他惩罚回归问题的完整解路径。它们通过按有序的调节参数值序列依次求解构成解路径的问题,而不是分别求解每个问题,从而改进了冷启动算法。然而,将路径式坐标下降算法扩展到更一般的 bridge 或幂族 $\ell_q$ 惩罚具有挑战性。由于 $\ell_q$ 惩罚回归问题可能是非凸的,并且求解负担尤其沉重,因此需要更快的算法来计算这些惩罚的解路径。在本文中,我们证明 $\ell_q$ 惩罚回归问题的一种重新参数化更适合路径式坐标下降算法。这使我们能够在实践中改进 $\ell_q$ 惩罚回归问题的模式阈值函数的计算,并引入两种独立的路径式算法。我们证明,任一路径式算法都比相应的冷启动替代方案更快,并证明不同的路径式算法可能更有可能达到更好的解。

英文摘要:

Pathwise coordinate descent algorithms have been used to compute entire solution paths for lasso and other penalized regression problems quickly with great success. They improve upon cold start algorithms by solving the problems that make up the solution path sequentially for an ordered set of tuning parameter values, instead of solving each problem separately. However, extending pathwise coordinate descent algorithms to more the general bridge or power family of $\ell_q$ penalties is challenging. Faster algorithms for computing solution paths for these penalties are needed because $\ell_q$ penalized regression problems can be nonconvex and especially burdensome to solve. In this paper, we show that a reparameterization of $\ell_q$ penalized regression problems is more amenable to pathwise coordinate descent algorithms. This allows us to improve computation of the mode-thresholding function for $\ell_q$ penalized regression problems in practice and introduce two separate pathwise algorithms. We show that either pathwise algorithm is faster than the corresponding cold-start alternative, and demonstrate that different pathwise algorithms may be more likely to reach better solutions.

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。

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