基于MPI+OpenMP的时间域航空电磁快速正演算法

doi:10.11720/wtyht.2020.1460

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Abstract

The time domain finite element algorithm has been widely used in airborne electromagnetic three-dimensional forward modeling. However, due to the large airborne electromagnetic measurement area and dense sampling, the forward calculation is huge, and the traditional serial algorithm cannot meet the calculation efficiency requirements. In view of such a situation, the authors carried out parallel acceleration algorithm research to solve the problem of insufficient computational efficiency. Based on the limited range of influence of aviation electromagnetic system, the local grid technology is used to divide the computing task into multiple sub-grids, that is, a set of grids for each source, and the forward calculations of each grid are independent of each other, and hence no data dependency is existent and there is good parallelism. In this paper, MPI technology is used to allocate multiple sub-grid forward tasks, and parallel computing is performed on each process. For each forward subgrid, in the forward modeling of the time domain finite element algorithm, the parallel matrix is calculated by OpenMP technology. The numerical simulation results of the typical electrical model show that the MPI+OpenMP parallel forward algorithm developed in this paper can effectively improve the forward speed, and the maximum acceleration ratio can reach 10 times.

Key words： time-domain airborne EM MPI OpenMP finite element

Received: 24 September 2019 Published: 22 April 2020

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Corresponding Authors: Xiu LI

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	Yun-Tong REN
	Xiu LI
	Yan-Fu QI
	Hua-Ke CAO

Cite this article:

Yun-Tong REN,Xiu LI,Yan-Fu QI, et al. Research on time domain airborne electromagnetic fast forward algorithm based on MPI+OpenMP[J]. Geophysical and Geochemical Exploration, 2020, 44(2): 290-299.

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https://www.wutanyuhuatan.com/EN/10.11720/wtyht.2020.1460 OR https://www.wutanyuhuatan.com/EN/Y2020/V44/I2/290

Moving footprint for time-domian airborne EM system

Global grid vs. local grid
((a) is a Global grid; (b) (c) (d) is a local grid)

OpenMP parallel mode schematic

MPI parallel mode schematic

Airborne transient electromagnetic three-dimensional Forward modeling parallel computing flow chart

Schematic diagram of the horizontal plate model

Comparison of electromagnetic response results between global grid serial computing and local grid parallel computing

Line forward calculation statistics based on MPI+OpenMP parallel acceleration strategy

Acceleration ratio (a) and parallel efficiency (b) for different node numbers

Calculation of complex models

Calculation statistics table

Multiple trajectory map of complex model main section (x=0 line)

Complex terrain anomaly response surface map

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