Density estimation for elliptic PDE with random input by preintegration and quasi-Monte Carlo methods

Fuente: arXiv
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Main Authors: Gilbert, Alexander D., Kuo, Frances Y., Srikumar, Abirami
Format: Preprint
Published: 2024
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_version_ 1866909328148004864
author Gilbert, Alexander D.
Kuo, Frances Y.
Srikumar, Abirami
author_facet Gilbert, Alexander D.
Kuo, Frances Y.
Srikumar, Abirami
contents In this paper, we apply quasi-Monte Carlo (QMC) methods with an initial preintegration step to estimate cumulative distribution functions and probability density functions in uncertainty quantification (UQ). The distribution and density functions correspond to a quantity of interest involving the solution to an elliptic partial differential equation (PDE) with a lognormally distributed coefficient and a normally distributed source term. There is extensive previous work on using QMC to compute expected values in UQ, which have proven very successful in tackling a range of different PDE problems. However, the use of QMC for density estimation applied to UQ problems will be explored here for the first time. Density estimation presents a more difficult challenge compared to computing the expected value due to discontinuities present in the integral formulations of both the distribution and density. Our strategy is to use preintegration to eliminate the discontinuity by integrating out a carefully selected random parameter, so that QMC can be used to approximate the remaining integral. First, we establish regularity results for the PDE quantity of interest that are required for smoothing by preintegration to be effective. We then show that an $N$-point lattice rule can be constructed for the integrands corresponding to the distribution and density, such that after preintegration the QMC error is of order $\mathcal{O}(N^{-1+ε})$ for arbitrarily small $ε>0$. This is the same rate achieved for computing the expected value of the quantity of interest. Numerical results are presented to reaffirm our theory.
format Preprint
id arxiv_https___arxiv_org_abs_2402_11807
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Density estimation for elliptic PDE with random input by preintegration and quasi-Monte Carlo methods
Gilbert, Alexander D.
Kuo, Frances Y.
Srikumar, Abirami
Numerical Analysis
65D30, 65D32, 35J25, 62G07
In this paper, we apply quasi-Monte Carlo (QMC) methods with an initial preintegration step to estimate cumulative distribution functions and probability density functions in uncertainty quantification (UQ). The distribution and density functions correspond to a quantity of interest involving the solution to an elliptic partial differential equation (PDE) with a lognormally distributed coefficient and a normally distributed source term. There is extensive previous work on using QMC to compute expected values in UQ, which have proven very successful in tackling a range of different PDE problems. However, the use of QMC for density estimation applied to UQ problems will be explored here for the first time. Density estimation presents a more difficult challenge compared to computing the expected value due to discontinuities present in the integral formulations of both the distribution and density. Our strategy is to use preintegration to eliminate the discontinuity by integrating out a carefully selected random parameter, so that QMC can be used to approximate the remaining integral. First, we establish regularity results for the PDE quantity of interest that are required for smoothing by preintegration to be effective. We then show that an $N$-point lattice rule can be constructed for the integrands corresponding to the distribution and density, such that after preintegration the QMC error is of order $\mathcal{O}(N^{-1+ε})$ for arbitrarily small $ε>0$. This is the same rate achieved for computing the expected value of the quantity of interest. Numerical results are presented to reaffirm our theory.
title Density estimation for elliptic PDE with random input by preintegration and quasi-Monte Carlo methods
topic Numerical Analysis
65D30, 65D32, 35J25, 62G07
url https://arxiv.org/abs/2402.11807