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为提高水平层状介质中三维异常体的电磁波散射精确数值模拟的效率,提出了一种将求解积分方程的对角张量近似(DTA)和稳定型双共轭梯度快速Fourier变换(BCGS-FFT)混合应用的算法。根据不同回代方式得到了两种近似,即DTA1和DTA2,二者均可以通过快速Fourier变换技术加速。DTA既可以作为BCGS-FFT算法的初始猜测值也可以作为它的预条件因子,从而使得这种混合算法能以比传统的BCGS-FFT算法更少的迭代次数精确求解电磁波散射场。对DTA、混合DTA-BCGS以及BCGS-FFT的精度和收敛性进行了对比,结果表明,DTA2改进型的对角张量近似可使计算精度进一步提高,而混合DTA-BCGS能以更少的迭代次数达到与传统的BCGS-FFT完全相同的精度。
In order to improve the efficiency of accurate numerical simulation of electromagnetic scattering of three-dimensional anomaly bodies in horizontal layered media, a new method, called diagonal tensor approximation (DTA) and stable biconjugate gradient Fourier transform (BCGS-FFT) ) Mixed application of the algorithm. Two approximations are obtained based on the different back-substitution methods, namely DTA1 and DTA2, both of which can be accelerated by the fast Fourier transform technique. DTA can be used as both the initial guess and the preconditioner of the BCGS-FFT algorithm, so that the hybrid algorithm can accurately solve the electromagnetic scattering field with fewer iterations than the traditional BCGS-FFT algorithm. The accuracy and convergence of DTA, mixed DTA-BCGS and BCGS-FFT are compared. The results show that the improved DTA2 diagonal tensor approximation can further improve the computational accuracy, while the hybrid DTA-BCGS can use fewer iterations The number of times is exactly the same as the traditional BCGS-FFT.