论文标题

通过采样从DPP学习:超越HKPV和对称性

Learning from DPPs via Sampling: Beyond HKPV and symmetry

论文作者

Bardenet, Rémi, Ghosh, Subhroshekhar

论文摘要

确定点过程(DPP)已成为推荐系统,特征选择或摘要提取的重要工具,从而利用了这些概率模型的内在能力,以促进样品多样性。从DPP进行采样的能力对于这些模型的实证研究至关重要。大多数精确的采样器都是由于Hough,Krishnapur,Peres和Virág(此后HKPV)而引起的光谱元算法的变体,这是一般时间和资源密集型的。对于具有对称内核的DPP,已经提出了可扩展的HKPV采样器,首先将项目的接地套件置于样本,或者迫使内核变为低秩,例如NYSTRöm-type分解。 在目前的工作中,我们的贡献与HKPV截然不同。利用这样一个事实,即可以通过仅采样DPP的某些关键观察物(所谓的线性统计数据)来有效地实现这一事实,我们调用了一种可观察到的单个决定性物质的laplace转换的表达式,该laplace具有单一的决定因素,该依赖于完全普遍性。通过数值分析结合传统的低级近似技术与拉普拉斯反转算法,我们展示了如何直接近似DPP的线性统计量的分布函数。然后,该分布函数可以根据要求将其用于假设检验或实际采样线性统计量。我们的方法是可扩展的,并且适用于非常通用的DPP,除了传统的对称内核之外。

Determinantal point processes (DPPs) have become a significant tool for recommendation systems, feature selection, or summary extraction, harnessing the intrinsic ability of these probabilistic models to facilitate sample diversity. The ability to sample from DPPs is paramount to the empirical investigation of these models. Most exact samplers are variants of a spectral meta-algorithm due to Hough, Krishnapur, Peres and Virág (henceforth HKPV), which is in general time and resource intensive. For DPPs with symmetric kernels, scalable HKPV samplers have been proposed that either first downsample the ground set of items, or force the kernel to be low-rank, using e.g. Nyström-type decompositions. In the present work, we contribute a radically different approach than HKPV. Exploiting the fact that many statistical and learning objectives can be effectively accomplished by only sampling certain key observables of a DPP (so-called linear statistics), we invoke an expression for the Laplace transform of such an observable as a single determinant, which holds in complete generality. Combining traditional low-rank approximation techniques with Laplace inversion algorithms from numerical analysis, we show how to directly approximate the distribution function of a linear statistic of a DPP. This distribution function can then be used in hypothesis testing or to actually sample the linear statistic, as per requirement. Our approach is scalable and applies to very general DPPs, beyond traditional symmetric kernels.

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