arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2002.02833math.NAastro-ph.COcs.NAphysics.comp-ph
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宇宙微波背景数据时域分量分离的加速线性系解算器

Accelerating linear system solvers for time domain component separation of cosmic microwave background data

J. Papež, L. Grigori, R. Stompor

摘要:

成分分离是任何现代宇宙微波背景(CMB)数据分析管道的关键阶段之一。这是一个固有的非线性过程,通常涉及一系列的线性系的顺序解决方案,类似的,虽然不是相同的系统矩阵,推导出不同的数据模型相同的数据集。这种序列例如在关于前景参数的数据似然的最大化或其后验分布的采样中出现。然而,它们在许多其他情况下也很常见。在这项工作中,我们考虑直接在测量(时间)域中解决组件分离问题,这可能比更标准的基于像素的方法具有许多重要的优势,特别是如果存在不可忽略的时域噪声相关性,因为它是常见的情况。然而,基于时域的方法意味着由于需要操纵时域数据集的全部体积而导致的显著的计算工作量。为了应对这一挑战,我们提出并研究了高效的求解器,适用于解决基于时域的组件分离系统及其序列,并且能够利用从以前的解决方案中获得的信息。这是通过调整后续系统的初始猜测或通过所谓的子空间循环来实现的,子空间循环允许构建逐渐更有效的两级预处理器。我们报告了一个整体的速度超过解决系统独立的一个因素,近7,或5,在工作的例子启发分别由似然最大化和似然抽样程序,我们认为在这项工作中。

英文摘要:

Component separation is one of the key stages of any modern, cosmic microwave background (CMB) data analysis pipeline. It is an inherently non-linear procedure and typically involves a series of sequential solutions of linear systems with similar, albeit not identical system matrices, derived for different data models of the same data set. Sequences of this kind arise for instance in the maximization of the data likelihood with respect to foreground parameters or sampling of their posterior distribution. However, they are also common in many other contexts. In this work we consider solving the component separation problem directly in the measurement (time) domain, which can have a number of important advantageous over the more standard pixel-based methods, in particular if non-negligible time-domain noise correlations are present as it is commonly the case. The time-domain based approach implies, however, significant computational effort due to the need to manipulate the full volume of time-domain data set. To address this challenge, we propose and study efficient solvers adapted to solving time-domain-based, component separation systems and their sequences and which are capable of capitalizing on information derived from the previous solutions. This is achieved either via adapting the initial guess of the subsequent system or through a so-called subspace recycling, which allows to construct progressively more efficient, two-level preconditioners. We report an overall speed-up over solving the systems independently of a factor of nearly 7, or 5, in the worked examples inspired respectively by the likelihood maximization and likelihood sampling procedures we consider in this work.

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