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arXiv 2409.02673math.NAcs.NA
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一种无粗传播器的Parareal算法?

A Parareal algorithm without Coarse Propagator?

Martin J. Gander, Mario Ohlberger, Stephan Rave

AI总结:

本文首次提出一种无粗传播器的Parareal算法,给出适用于空间近似粗传播器的新收敛证明,并用数值实验验证其对抛物型问题有效、对双曲型问题不适用。

摘要:

Parareal算法于2001年提出,目的是在时间方向上并行求解演化问题。它基于并行的精细时间传播器F和串行的粗时间传播器G,二者交替求解演化问题并迭代收敛到精细解。粗传播器G是Parareal中非常重要的组成部分,这一点在收敛分析中可以看出。我们在此首次提出一种无粗传播器的Parareal算法,并解释为什么这种方法对抛物型问题可以非常有效。我们给出了一个新的收敛证明,适用于在空间上进行近似的粗传播器,这与更经典的在时间上进行近似的粗传播器形成对比,并且我们的证明在不存在粗传播器的情况下也适用。我们用数值实验说明了理论结果,并解释了为什么这种方法不能用于双曲型问题。

英文摘要:

The Parareal algorithm was invented in 2001 in order to parallelize the solution of evolution problems in the time direction. It is based on parallel fine time propagators called F and sequential coarse time propagators called G, which alternatingly solve the evolution problem and iteratively converge to the fine solution. The coarse propagator G is a very important component of Parareal, as one sees in the convergence analyses. We present here for the first time a Parareal algorithm without coarse propagator, and explain why this can work very well for parabolic problems. We give a new convergence proof for coarse propagators approximating in space, in contrast to the more classical coarse propagators which are approximations in time, and our proof also applies in the absence of the coarse propagator. We illustrate our theoretical results with numerical experiments, and also explain why this approach can not work for hyperbolic problems.

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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