迭代计算

The SEM poles have been calculated theoretically by using the iterative method and contour integral method so far, but the both methods have many defects.

为了从理论上得到散射体的极点，人们提出了许多的数值计算方法，如Newton迭代法，Muller迭代法和围线积分法等，但都存在种种缺陷。

The integral equation is convergent for any conductivity distribution and frequency if iterative solvers are used.

提出一种应用迭代法求解新积分方程的迭代初值优化选择方法，并通过具体算例对比说明该方法可使频率域电磁测深三维模拟的计算效率得到有效提高。

If the Landweber method and pre-iteration method were convergent, the residue sequence would be monotone decreasing. By analyzing the convergence, the fact is demonstrated that for the severe ill-conditioned matrix of sensitivity coefficient, because of the limitation of the precision of the computer, the residue sequence is not monotone decreasing; thereby the reconstruction images diverge from the true distribution of the conductivity. So the generalized inverse method with threshold is established and the selection way of the regularization parameter is presented, by which the better images are reconstructed.

Landweber法和预迭代法收敛，则其残差序列单调递减，通过对它们的收敛性进行分析，证实对于病态性严重的灵敏度系数矩阵，由于受计算精度的限制，迭代过程中的残差序列不再单调递减，从而导致重建图象偏离实际电导率分布，因此作者建立了带阈值的广义逆算法，提出了规则化参数选择方法，获得了较好的图象重建质量。

It can be found that the IPCA, as a non-iterative method, can obtain one principal component by only one calculating process. Therefore the IPCA is not only fast in calculation, but can avoid the cumulative error suffered by iterative methods.

使用模拟和实验HPLC-DAD数据对IPCA进行了验证，结果表明IPCA是一种非迭代方法，只需要完成一次计算过程即可得到一个主成分，因此IPCA不仅能够显著提高运算速度，而且可以避免迭代法中的误差积累问题。

This paper is devoted to solving linear saddle point problems, Specifically, We consider nonsymmetric systems, written as usual in block form, where the upper left block is an invertible linear operator with positive definite symmetric part. Such saddle point problems arise, for example, in certain finite element and finite difference discretizations of NavierStokes equations, Oseen equations, and mixed finite element discretization of second order convection-diffusion problems.

中文题名求解鞍点问题的迭代方法副题名外文题名论文作者冯丽红导师曹志浩教授学科专业计算数学研究领域\研究方向学位级别博士学位授予单位复旦大学学位授予日期2002 论文页码总数87页关键词鞍点问题迭代方法网格离散线性方程组馆藏号BSLW /2003 /O241 /15 论文针对鞍点问题的求解分析了一些典型的快速算法。

According to the space domain iteration method of the Fredholm integral equation of the first kind, the wave number domain iteration formula is deduced for calculating the wave spectrum of the potential field on a lower horizontal plane.

根据第一类Fredholm积分方程的空间域迭代解法，推导出计算向下延拓水平面上位场波谱的波数域迭代公式。

Regarding iterated processes as objective function,parameters of algebra iterated system as design variables,and boundary condition of iterated variables as constrains,a new optimum method was proposed,which was used to calculate bifurcation of Logistic mapping.

以迭代过程关系构成目标函数，参数为设计变量，迭代变量的边界为约束，建立关于分支值计算的新方法含约束条件的最优化程序算法。

In this paper, we consider the iterative methods for computing the generalized Bott-Duffin inverse.

该文我们考虑计算广义Bott-Duffin逆的迭代方法，研究了迭代公式收敛的充分必要条件。

It Newton iteration is used in the analysis of math value,and the simplicity formula is given to resolve(including original initial value formula and advanced approximation formula),which can be characterized by fast speed and easy remembering.

采用数值分析中的牛顿迭代法求反渐开线函数的根，并给出了符合精度要求的解算反渐开线函数的简单公式(包括原始初值公式和近似值精化公式)，具有迭代收敛速度快、简单易记的优点，它们适用于[0，π/2]的全区段，免除了分段计算的烦恼，并运用VB编写计算机程序，从而实现反渐开线函数快速求根的目的。

By using accelerating Aitken method in iterative method of nonlinear equations, a new modified method is given. The method is applied to modified Newton method, thereby a new method is developed, which is faster and stable. Also, its algorithm is given. Numerical results show that the new method is very efficient.

通过对非线性方程组的迭代法引入Aitken加速技术，设计了一种非线性方程组的迭代解法的加速方法；将该方法与M步Newton法相结合，得到一种收敛速度快而且计算稳定的方法，并给出了具体算法；数值结果表明了新算法是有效的。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。