共查询到17条相似文献,搜索用时 250 毫秒
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时域体电场积分方程性态较好,但时域面积分方程性态较差,这就造成体面耦合的时域电场积分方程在迭代求解时经常遇到收敛较慢的问题,无法满足工程需要,并且一般预条件技术获得的加速效果也不甚理想。因此,时域体面积分方程迭代求解时间过长已成为体面积分方程在实际工程应用中的核心问题。针对时域体面电场积分方程矩阵性态差的问题,提出一种引入分块预条件方法(BMP),可以加快矩阵迭代收敛的速度。将时域体面积分方程的矩阵分解成3块矩阵相乘的形式,而这3块矩阵都是稀疏的,并通过几个体面算例说明该预条件技术的效率。 相似文献
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本文针对体积分方程矩量法(VIE-MoM)分析三维非均匀介质电磁散射问题所导出的大型矩阵方程的求解问题, 基于多层快速极子技术(MLFMA)算法研究了快速近似迭代方法.提出了一种基于MLFMA分组方案对系数矩阵进行重组并提取强耦合元素的近场预条件器的构造方法,有效地提高了广义最小余量法(GMRES)的迭代收敛速度.提出了一种在迭代计算过程中的近似矩阵向量乘积方案,明显降低了单步计算过程中MLFMA远区耦合作用的计算时间.计算实例表明,采用本文的迭代加速技术可使计算速度提高3至5倍,有效地提高了VIE-MoM大型矩阵方程的迭代求解速度. 相似文献
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高阶矩量法在计算电磁学中的应用越来越广泛, 为了进一步提高其计算规模, 引入并行的自适应交叉近似压缩算法(Adaptive Cross Approximation algorithm, ACA).该算法首先采用非均匀有理B样条建模(Non-Uniform Rational B-Splines, NURBS)的方法进行面片分组; 然后利用矩量法中远区阻抗矩阵的低秩特性进行ACA压缩; 最后采用稀疏近似逆预条件(Sparse Pattern Approximate Inverse preconditioning, SPAI)的共轭梯度法(Conjugate Gradient method, CG)快速求解矩阵方程.该算法中的ACA压缩过程和迭代求解过程都特别适合并行计算.数值实验表明, 对于电大尺寸问题, ACA压缩后的矩阵占用的内存远远低于原矩阵, 而预条件的共轭梯度法可以很快收敛.此外该算法在大规模并行时的效率较高. 相似文献
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论文提出了一种叠层矩量法分析多尺度目标电磁特性。论文采用矩量法直接计算强相互作用区域,多层矩阵压缩方法(MLMCM)和多层快速多极子方法(MLFMA)分别用于加速计算低频和高频作用区域。论文通过使用多分辨ILU(MR-ILU)预条件加速迭代求解矩量法离散多尺度目标产生的病态矩阵方程。通过分析实际多尺度目标电磁特性证明论文方法的有效性。 相似文献
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本文利用多频多入射方向的Newton-Kantorovich方法,结合矩量法求解利用后向近场散射数据,对二维导体目标外形成像而产生的非线性耦合积分方程,然后采用基于Gram-Schedmit正交化的伪逆技术求解所得的病态线性方程组,利用最小二乘法给出迭代的初值。为减小计算量,当迭代到一定程度时,改用修正的Newton-Kantorovich方法,同时,每迭代三次,采用一次加速收敛公式。最后,以数值结果证明了本方法的有效性及抗噪声性能。 相似文献
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求解复杂载体天线辐射问题的近场预条件技术 总被引:2,自引:0,他引:2
提出了一种近场预条件技术与LDU分解法相结合的新技术,用于加速矩量法(MoM)分析复杂载体上线天线辐射问题中线性方程组的迭代求解.通过LDU分解可将系数矩阵中表示载体上单元相互作用的具有对角占优特性的子阵分离出来,构造一个矩阵分解形式的预条件阵.结合广义最小留数(GMRES)法,分别对装载在两个简单形体和一架大型飞机模型上的线天线的辐射问题进行了求解.数值结果表明,该方法可大大加快线性方程组迭代求解的收敛速度,提高分析计算效率. 相似文献
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利用后向近场散射数据成像的Newton—Kantorovich方法研究 总被引:1,自引:1,他引:0
本文利用多频多入射方向的Newton-Kantorovich方法,结合矩量法求解利用后向近场散射数据,对二维导体目标外形成像而产生的非线性耦合积分方程,然后采用基于Gram-Schedmit正交化的伪逆技术求解所得的病态线性方程组,利用最小二乘法给出迭代的初值,为减小计算量,当迭代到一定程度时,改用修正的Newton-Kantorovich方法,同时,每迭代三次,采用一次加速收敛公式,最后,以数值 相似文献
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An efficient preconditioner for electromagnetic integral equations using predefined wavelet packet basis 总被引:1,自引:0,他引:1
Hai Deng Hao Ling 《Antennas and Propagation, IEEE Transactions on》2002,50(11):1633-1640
An approximate-inverse preconditioner based on the predefined wavelet packet (PWP) basis is proposed for the fast iterative solution of electromagnetic integral equations. The PWP basis is designed to achieve a sparse representation of the moment matrix and the preconditioner is constructed by inverting the block-diagonal approximation of the PWP-based moment matrix and transforming the results into the space domain. Numerical results show that the PWP preconditioner is effective in accelerating the convergence rate of iterative solution to moment equations. It is also demonstrated that by properly designing the block-diagonal matrix and computing the matrix elements, the total computational complexity and memory costs for the preconditioner can be kept to O(NlogN). 相似文献
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Diagonal preconditioners for the EFIE using a wavelet basis 总被引:1,自引:0,他引:1
The electric field integral equation (EFIE) has found widespread use and in practice has been accepted as a stable method. However, mathematically, the solution of the EFIE is an “ill-posed” problem. In practical terms, as one uses more and more expansion and testing functions per wavelength, the condition number of the resulting moment-method matrix increases (without bound). This means that for high-sampling densities, iterative methods such as conjugate gradients converge more slowly. However, there is a way to change all this. The EFIE is considered using a wavelet basis for expansion and for testing functions. Then, the resulting matrix is multiplied on both sides by a diagonal matrix. This results in a well-conditioned matrix which behaves much like the matrix for the magnetic field integral equation (MFIE). Consequences for the stability and convergence rate of iterative methods are described 相似文献
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R. S. Chen K. F. Tsang Edward K. N. Yung 《Journal of Infrared, Millimeter and Terahertz Waves》2000,21(8):1281-1301
In this paper, symmetric successive overrelaxation (SSOR) preconditioned CG technique are introduced into method of lines (MOL) to further enhance the computational efficiency of this semi-analytic method. Millimeter wave scattering by an infinite plane metallic grating is used as the examples to describe its implementation, whose analysis usually needs fast algorithms because of electrically large dimension. For arbitrary incident wave, Helmholz equation and boundary condition are used to calculate the impedance matrix and then to obtain reduced current-voltage linear matrix equation in spatial domain. An effective symmetric successive overrelaxation preconditioned conjugate gradient iterative method, SSOR-PCG, is chosen to solve this matrix equation. With SSOR as the preconditioner as well as its efficient implementing in CG algorithm, PCG method can converge to accurate solution in much fewer iteration steps. 相似文献
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A single-level low rank IE-QR algorithm for PEC scattering problems using EFIE formulation 总被引:1,自引:0,他引:1
Seung Mo Seo Jin-Fa Lee 《Antennas and Propagation, IEEE Transactions on》2004,52(8):2141-2146
This paper presents a single-level matrix compression algorithm, termed IE-QR, based on a low-rank approximation to speed up the electric field integral equation (EFIE) formulation. It is shown, with the number of groups chosen to be proportional to N/sup 1/2/, where N is the number of unknowns, the memory and CPU time for the resulting algorithm are both O(N/sup 1.5/). The unique features of the algorithm are: a. The IE-QR algorithm is based on the near-rank-deficiency property for well-separated groups. This near-rank-deficiency assumption holds true for many integral equation methods such as Laplacian, radiation, and scattering problems in electromagnetics (EM). The same algorithm can be adapted to other applications outside EM with few or no modifications; and, b. The rank estimation is achieved by a dual-rank process, which ranks the transmitting and receiving groups, respectively. Thus, the IE-QR algorithm can achieve matrix compression without assembling the entire system matrix. Also, a "geometric-neighboring" preconditioner is presented in this paper. This "geometric-neighboring" preconditioner when used in conjunction with GMRES is proven to be both efficient and effective for solving the compressed matrix equations. 相似文献
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在电磁散射问题中,由均匀介质和金属组合而成的多区域结构目标在天线仿真、雷达成像等工程问题中有着广泛应用. 针对多区域目标的散射问题,研究了不连续伽辽金(discontinuous Galerkin, GD)方法在多区域面积分(surface integral equation, SIE)矩量法中的使用,同时提出了一种优化的距离稀疏预处理(optimized distance sparse preconditioner, O-DSP)方法。该方法根据阻抗矩阵中不同积分算子随距离变化的特性来个性化选择预处理矩阵,进一步增加了预处理矩阵的稀疏性. 数值计算表明,相比之前的距离稀疏预处理方法,优化的预处理矩阵非零元素仅为以前的一半,而且具有相同加速迭代效果. 相似文献