Solution of second kind Fredholm integral equations by means of Gauss and anti-Gauss quadrature rules

This paper is concerned with the numerical approximation of Fredholm integral equations of the second kind. A Nyström method based on the anti-Gauss quadrature formula is developed and investigated in terms of stability and convergence in appropriate weighted spaces. The Nyström interpolants corresponding to the Gauss and the anti-Gauss quadrature rules are proved to furnish upper and lower bounds for the solution of the equation, under suitable assumptions which are easily verified for a particular weight function. Hence, an error estimate is available, and the accuracy of the solution can be improved by approximating it by an averaged Nyström interpolant. The effectiveness of the proposed approach is illustrated through different numerical tests.

On the Comparison of Gauss and Hybrid Methods and their Application to Calculation of Definite Integrals

As is known there is the wide class of methods for calculation of the definite integrals constructed by the well-known scientists as Newton, Gauss, Chebyshev, Cotes, Simpson, Krylov and etc. It seems that to receive a new result in this area is impossible. The aim of this work is the applied some general form of hybrid methods to computation of definite integral and compares that with the Gauss method. The generalization of the Gauss quadrature formula have been fulfilled in two directions. One of these directions is the using of the implicit methods and the other is the using of the advanced (forward-jumping) methods. Here have compared these methods by shown its advantages and disadvantages in the results of which have recommended to use the implicit method with the special structure. And also are constructed methods, which have applied to calculation of the definite integral with the symmetric bounders. As is known, one of the popular methods for calculation of the definite integrals with the symmetric bounders is the Chebyshev method. Therefore, here have defined some relations between of the above mentioned methods. For the application constructed, here methods are defined the necessary conditions for its convergence. The receive results have illustrated by calculation the values for some model integral using the methods with the degree p  8.

A p-version of the collocation method for solving the Fredholm integral equations of the second kind in the Mathematica environment

Предложена и реализована p-версия метода коллокации численного решения интегральных уравнений Фредгольма второго рода. В данной реализации осуществлены возможности варьирования степени полинома в полиномиальном представлении приближенного решения уравнений и варьирования количества узлов используемой квадратурной формулы Гаусса для влияния на точность решения. Исследовано влияние числа точек коллокации, использованных для аппроксимации решения, и количества узлов квадратурной формулы Гаусса на число обусловленности системы линейных алгебраических уравнений, к решению которой сводится построение приближенного решения, и на его точность путем численного решения примеров, в том числе приведенных в известных изданиях. Предложенный алгоритм реализован на языке программного пакета Mathematica. Во всех рассмотренных примерах предложенная версия метода коллокации позволила достичь точности решения уравнений, близкой к уровню машинных ошибок округления. Программный продукт, реализующий предложенную p-версию, получился достаточно компактным, а метод оказался экономичным: машинное время, необходимое для решения рассмотренных в работе задач, не превышало 3 секунды работы персонального компьютера. Описан алгоритм, позволяющий оценить точность приближенного решения по предложенной p-версии метода в тех случаях, когда точное решение интегрального уравнения неизвестно. A p-version of the collocation method for the numerical solution of Fredholm integral equations of the second kind is proposed and implemented. In the considered implementation, the possibilities are realized for the variation of the polynomial degree in the polynomial representation of the approximate solution of equations and the variation of the number of nodes of the employed Gauss quadrature formula to affect the solution accuracy. The influence of the number of collocation points used for the solution approximation and of the number of nodes of the Gauss quadrature formula on the condition number of the system of linear algebraic equations to the solution of which the construction of the approximate solution is reduced and on its accuracy are studied by the numerical solution of examples, including some examples presented in well-known publications. The proposed algorithm is implemented in the language of the program package Mathematica. In all considered examples, the proposed version of the collocation method has enabled us to reach the accuracy of the solution of equations, which is close to the level of the machine rounding errors. The program product implementing the proposed p-version has proved to be compact and the method turned out to be economical: the machine time required for the solution of problems considered in the paper did not exceed 3 seconds of the CPU time of a personal computer. We describe an algorithm allowing us to estimate the accuracy of the approximate solution obtained by the proposed p-version of the method in the cases where the exact solution of the integral equation is unknown.

A Spectral Numerical Method for Solving Distributed-Order Fractional Initial Value Problems

In this paper, we construct and analyze a Legendre spectral-collocation method for the numerical solution of distributed-order fractional initial value problems. We first introduce three-term recurrence relations for the fractional integrals of the Legendre polynomial. We then use the properties of the Caputo fractional derivative to reduce the problem into a distributed-order fractional integral equation. We apply the Legendre–Gauss quadrature formula to compute the distributed-order fractional integral and construct the collocation scheme. The convergence of the proposed method is discussed. Numerical results are provided to give insights into the convergence behavior of our method.

Development of Galerkin Method for Solving the Generalized Burger's-Huxley Equation

Numerical treatments for the generalized Burger's—Huxley GBH equation are presented. The treatments are based on cardinal Chebyshev and Legendre basis functions with Galerkin method. Gauss quadrature formula and El-gendi method are used to convert the problem into a system of ordinary differential equations. The numerical results are compared with the literatures to show efficiency of the proposed methods.