快速配置法中数值积分的误差控制策略

We propose two error control techniques for numerical integrations in fast multiscale collocation methods for solving Fredholm integral equations of the second kind with weakly singular kernels. Both techniques utilize quadratures for singular integrals using graded points. One has a polynomial order of accuracy if the integrand has a polynomial order of smoothness except at the singular point and the other has exponential order of accuracy if the integrand has an infinite order of smoothness except at the singular point. We estimate the order of convergence and computational complexity of the corresponding approximate solutions of the equation. We prove that the second technique preserves the order of convergence and computational complexity of the original collocation method. Numerical experiments are presented to illustrate the theoretical estimates.     

解不适定问题的一种多尺度方法

1 前言 数学物理反问题是应用数学领域中成长和发展最快的领域之一.反问题大多是不适定的.对于不适定问题的解法已有不少的学者进行探索和研究,Tikhonov正则化方法是一种理论上最完备而在实践上行之有效的方法(参见[5,6,7,8,13]).     

Fast Multilevel Methods for Solving Ill-posed Problems

1 Introduetion Many industrial and engineering applieations require numerieally solving ill-posed Problems. Regularization methods are employed to find approximate solutions of these problems.The choice of regularization     

MULTILEVEL AUGMENTATION METHODS FOR SOLVING OPERATOR EQUATIONS

We introduce multilevel augmentation methods for solving operator equations based on direct sum decompositions of the range space of the operator and the solution space of the operator equation and a matrix splitting scheme. We establish a general setting for the analysis of these methods, showing that the methods yield approximate solutions of the same convergence order as the best approximation from the subspace. These augmentation methods allow us to develop fast, accurate and stable nonconventional numerical algorithms for solving operator equations. In particular, for second kind equations, special splitting techniques are proposed to develop such algorithms. These algorithms are then applied to solve the linear systems resulting from matrix compression schemes using wavelet-like functions for solving Fredholm integral equations of the second kind. For this special case, a complete analysis for computational complexity and convergence order is presented. Numerical examples are included to demonstra     

RLW方程的Lagrange型二次广义差分法和双孤立波碰撞过程的数值模拟

本文提出一种求解正则长波(RLW)方程初边值问题的Lagrange型二次广义差分法,计算格式简单有效。利用该算法,我们数值模拟了单孤立波传播和双孤立波碰撞的过程。前者与精确解比较是相当吻合的。文章给出半离散和全离散格式的误差