In this article, we propose two efficient combined methods to compute the integral integral(1)(0) f(x)/x-c J(m) (omega x(r)) dx with a special and nonlinear oscillator x(r), where 0 = 0, 2r is an element of N+. One is...
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In this article, we propose two efficient combined methods to compute the integral integral(1)(0) f(x)/x-c J(m) (omega x(r)) dx with a special and nonlinear oscillator x(r), where 0 < c < 1, m >= 0, 2r is an element of N+. One is established by combining the complex integration method with the two-point taylor interpolation method. The other is to combine two complex integration methods. The explicit formula of the integral. +8 integral(+infinity)(0) 1/x-c J(m)(omega x(r))dx is expressed in terms of the Meijer.. function. Importantly, the rigorous error analysis is performed by a large amount of theoretical analysis. The asymptotic error estimates in inverse powers of omega are achieved. Finally, numerical experiments show the validity of theoretical analysis and the efficiency of the proposed methods. In addition, we make numerical comparisons between the two proposed combined methods and another combined method.
The recent article (J. Math. Anal. Appl. 494 (2021), Article number: 124 4 48) presented an asymptotic Filon-type method for computing the oscillatory integral with a special oscilla-tor and weak singularities, f0b x ...
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The recent article (J. Math. Anal. Appl. 494 (2021), Article number: 124 4 48) presented an asymptotic Filon-type method for computing the oscillatory integral with a special oscilla-tor and weak singularities, f0b x alpha (b - x)fi f (x)eiwxrdx, -1 < alpha , fi < 0 , 0 < b < + 00 , w E R , r E N +. In this article, we propose and analyze two different efficient and accurate quadrature methods for this singularly oscillatory integral. First, we give a two-pointtaylor interpo-lation method by using a two-pointtaylor polynomial instead of f (x ) . In addition, we propose a more efficient contour integration method. By exploiting the taylor polynomial of the function f at x = 0 , and then based on the additivity of the integration interval, we change the considered integral into two integrals. One integral can be efficiently com-puted by the contour integration method based on Cauchy Residue Theorem and gener-alized Gaussian-Laguerre quadrature rule. The other integral can be explicitly calculated by special functions. Specifically, we perform the rigorous error analysis of the proposed methods and obtain asymptotic error estimates in inverse powers of the frequency param-eter w. Ultimately, the proposed methods are compared with the asymptotic Filon-type method given in this work (J. Math. Anal. Appl. 494 (2021), Article number: 124 4 48) and the modified Filon-type method. At the same computational cost, the two-pointtaylor in-terpolation method and the asymptotic Filon-type method have a very close accuracy level. Their accuracy is higher than that of the modified Filon-type method, and the precision of the contour integration method is much higher than that of the asymptotic Filon-type method, the modified Filon-type method, and the two-point taylor interpolation method. We verify error analyses of the proposed methods by experimental results. Numerical ex-periments can also verify the efficiency and precision of the proposed methods. (c) 2022 Elsevier Inc. All
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