Simplest random walk for approximating Robin boundary value problems and ergodic limits of reflected diffusions

Fuente: arXiv
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Auteurs principaux: Leimkuhler, B., Sharma, A., Tretyakov, M. V.
Format: Preprint
Publié: 2020
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author Leimkuhler, B.
Sharma, A.
Tretyakov, M. V.
author_facet Leimkuhler, B.
Sharma, A.
Tretyakov, M. V.
contents A simple-to-implement weak-sense numerical method to approximate reflected stochastic differential equations (RSDEs) is proposed and analysed. It is proved that the method has the first order of weak convergence. Together with the Monte Carlo technique, it can be used to numerically solve linear parabolic and elliptic PDEs with Robin boundary condition. One of the key results of this paper is the use of the proposed method for computing ergodic limits, i.e. expectations with respect to the invariant law of RSDEs, both inside a domain in $\mathbb{R}^{d}$ and on its boundary. This allows to efficiently sample from distributions with compact support. Both time-averaging and ensemble-averaging estimators are considered and analysed. A number of extensions are considered including a second-order weak approximation, the case of arbitrary oblique direction of reflection, and a new adaptive weak scheme to solve a Poisson PDE with Neumann boundary condition. The presented theoretical results are supported by several numerical experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2006_15670
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Simplest random walk for approximating Robin boundary value problems and ergodic limits of reflected diffusions
Leimkuhler, B.
Sharma, A.
Tretyakov, M. V.
Numerical Analysis
Probability
60H35, 65C30, 60H10, 37H10
A simple-to-implement weak-sense numerical method to approximate reflected stochastic differential equations (RSDEs) is proposed and analysed. It is proved that the method has the first order of weak convergence. Together with the Monte Carlo technique, it can be used to numerically solve linear parabolic and elliptic PDEs with Robin boundary condition. One of the key results of this paper is the use of the proposed method for computing ergodic limits, i.e. expectations with respect to the invariant law of RSDEs, both inside a domain in $\mathbb{R}^{d}$ and on its boundary. This allows to efficiently sample from distributions with compact support. Both time-averaging and ensemble-averaging estimators are considered and analysed. A number of extensions are considered including a second-order weak approximation, the case of arbitrary oblique direction of reflection, and a new adaptive weak scheme to solve a Poisson PDE with Neumann boundary condition. The presented theoretical results are supported by several numerical experiments.
title Simplest random walk for approximating Robin boundary value problems and ergodic limits of reflected diffusions
topic Numerical Analysis
Probability
60H35, 65C30, 60H10, 37H10
url https://arxiv.org/abs/2006.15670