{"title":"当解的倒数为被积函数时,对非线性积分方程进行数值求解","authors":"Indranil Sarkar, Gaurav Singh","doi":"10.1098/rspa.2023.0310","DOIUrl":null,"url":null,"abstract":"The objective of the present work is to develop a numerical method for solving a nonlinear integral equation given by <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" display=\"block\"> <mml:mi>y</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo>=</mml:mo> <mml:mi>f</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo>+</mml:mo> <mml:msubsup> <mml:mo>∫</mml:mo> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> </mml:msubsup> <mml:mi>k</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo>,</mml:mo> <mml:mi>s</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mfrac> <mml:mn>1</mml:mn> <mml:mrow> <mml:msup> <mml:mrow> <mml:mo stretchy=\"false\">[</mml:mo> <mml:mi>y</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>s</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo stretchy=\"false\">]</mml:mo> </mml:mrow> <mml:mrow> <mml:mi>α</mml:mi> </mml:mrow> </mml:msup> </mml:mrow> </mml:mfrac> <mml:mo> </mml:mo> <mml:mtext>d</mml:mtext> <mml:mi>s</mml:mi> <mml:mo>,</mml:mo> </mml:math> where <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>y</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo>∈</mml:mo> <mml:msup> <mml:mi>C</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo stretchy=\"false\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\"false\">]</mml:mo> </mml:math> with <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>y</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo>></mml:mo> <mml:mn>0</mml:mn> </mml:math> , <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>f</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo>∈</mml:mo> <mml:mi>C</mml:mi> <mml:mo stretchy=\"false\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\"false\">]</mml:mo> </mml:math> with <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>f</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> <mml:mo>≥</mml:mo> <mml:mn>0</mml:mn> </mml:math> , the kernel function <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>k</mml:mi> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo>,</mml:mo> <mml:mi>s</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> </mml:math> is non-negative and continuous on <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mo stretchy=\"false\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\"false\">]</mml:mo> <mml:mo>×</mml:mo> <mml:mo stretchy=\"false\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\"false\">]</mml:mo> </mml:math> and <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>α</mml:mi> <mml:mo>></mml:mo> <mml:mn>0</mml:mn> </mml:math> . The existence of a continuous positive solution of this equation is well-established in the literature. However, there is no reported method to solve it numerically for any <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>α</mml:mi> <mml:mo>></mml:mo> <mml:mn>0.</mml:mn> </mml:math> To attain the desired objective, the renowned Chebyshev collocation method is used. Having unknown Chebyshev coefficients, this method converts the integral equation into a matrix equation that produces a set of nonlinear algebraic equations. To solve these equations, computationally, the well-established Newton’s method is employed. To validate the effectiveness and precision of the method, various numerical examples with well-defined exact solutions are examined. Obtained numerical solutions confirm the accuracy and validity of the numerical method.","PeriodicalId":20716,"journal":{"name":"Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"121 1","pages":"0"},"PeriodicalIF":2.9000,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Numerically solving a nonlinear integral equation when the reciprocal of the solution lies in the integrand\",\"authors\":\"Indranil Sarkar, Gaurav Singh\",\"doi\":\"10.1098/rspa.2023.0310\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The objective of the present work is to develop a numerical method for solving a nonlinear integral equation given by <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" display=\\\"block\\\"> <mml:mi>y</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> <mml:mo>=</mml:mo> <mml:mi>f</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> <mml:mo>+</mml:mo> <mml:msubsup> <mml:mo>∫</mml:mo> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> </mml:msubsup> <mml:mi>k</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo>,</mml:mo> <mml:mi>s</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> <mml:mfrac> <mml:mn>1</mml:mn> <mml:mrow> <mml:msup> <mml:mrow> <mml:mo stretchy=\\\"false\\\">[</mml:mo> <mml:mi>y</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>s</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> <mml:mo stretchy=\\\"false\\\">]</mml:mo> </mml:mrow> <mml:mrow> <mml:mi>α</mml:mi> </mml:mrow> </mml:msup> </mml:mrow> </mml:mfrac> <mml:mo> </mml:mo> <mml:mtext>d</mml:mtext> <mml:mi>s</mml:mi> <mml:mo>,</mml:mo> </mml:math> where <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\"> <mml:mi>y</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> <mml:mo>∈</mml:mo> <mml:msup> <mml:mi>C</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo stretchy=\\\"false\\\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\\\"false\\\">]</mml:mo> </mml:math> with <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\"> <mml:mi>y</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> <mml:mo>></mml:mo> <mml:mn>0</mml:mn> </mml:math> , <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\"> <mml:mi>f</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> <mml:mo>∈</mml:mo> <mml:mi>C</mml:mi> <mml:mo stretchy=\\\"false\\\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\\\"false\\\">]</mml:mo> </mml:math> with <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\"> <mml:mi>f</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> <mml:mo>≥</mml:mo> <mml:mn>0</mml:mn> </mml:math> , the kernel function <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\"> <mml:mi>k</mml:mi> <mml:mo stretchy=\\\"false\\\">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo>,</mml:mo> <mml:mi>s</mml:mi> <mml:mo stretchy=\\\"false\\\">)</mml:mo> </mml:math> is non-negative and continuous on <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\"> <mml:mo stretchy=\\\"false\\\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\\\"false\\\">]</mml:mo> <mml:mo>×</mml:mo> <mml:mo stretchy=\\\"false\\\">[</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy=\\\"false\\\">]</mml:mo> </mml:math> and <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\"> <mml:mi>α</mml:mi> <mml:mo>></mml:mo> <mml:mn>0</mml:mn> </mml:math> . The existence of a continuous positive solution of this equation is well-established in the literature. However, there is no reported method to solve it numerically for any <mml:math xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\"> <mml:mi>α</mml:mi> <mml:mo>></mml:mo> <mml:mn>0.</mml:mn> </mml:math> To attain the desired objective, the renowned Chebyshev collocation method is used. Having unknown Chebyshev coefficients, this method converts the integral equation into a matrix equation that produces a set of nonlinear algebraic equations. To solve these equations, computationally, the well-established Newton’s method is employed. To validate the effectiveness and precision of the method, various numerical examples with well-defined exact solutions are examined. Obtained numerical solutions confirm the accuracy and validity of the numerical method.\",\"PeriodicalId\":20716,\"journal\":{\"name\":\"Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences\",\"volume\":\"121 1\",\"pages\":\"0\"},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2023-10-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1098/rspa.2023.0310\",\"RegionNum\":3,\"RegionCategory\":\"综合性期刊\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MULTIDISCIPLINARY SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1098/rspa.2023.0310","RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MULTIDISCIPLINARY SCIENCES","Score":null,"Total":0}
引用次数: 0
摘要
本文的目的是建立一种求解非线性积分方程的数值方法:y (t) = f (t) +∫1k (t, s) 1 [y (s)] α d s,其中y (t)∈c2 [0,1], y (t) >0, f (t)∈C[0,1],且f (t)≥0,则核函数k (t, s)在[0,1]×[0,1]和α >上是非负连续的;0。该方程的连续正解的存在性已在文献中得到证实。然而,对于任何α >0. 为了达到预期的目标,使用了著名的切比雪夫搭配法。由于切比雪夫系数未知,该方法将积分方程转化为矩阵方程,从而产生一组非线性代数方程。为了在计算上求解这些方程,采用了公认的牛顿法。为了验证该方法的有效性和精度,对具有明确精确解的各种数值算例进行了检验。得到的数值解验证了数值方法的准确性和有效性。
Numerically solving a nonlinear integral equation when the reciprocal of the solution lies in the integrand
The objective of the present work is to develop a numerical method for solving a nonlinear integral equation given by y(t)=f(t)+∫01k(t,s)1[y(s)]αds, where y(t)∈C2[0,1] with y(t)>0 , f(t)∈C[0,1] with f(t)≥0 , the kernel function k(t,s) is non-negative and continuous on [0,1]×[0,1] and α>0 . The existence of a continuous positive solution of this equation is well-established in the literature. However, there is no reported method to solve it numerically for any α>0. To attain the desired objective, the renowned Chebyshev collocation method is used. Having unknown Chebyshev coefficients, this method converts the integral equation into a matrix equation that produces a set of nonlinear algebraic equations. To solve these equations, computationally, the well-established Newton’s method is employed. To validate the effectiveness and precision of the method, various numerical examples with well-defined exact solutions are examined. Obtained numerical solutions confirm the accuracy and validity of the numerical method.
期刊介绍:
Proceedings A has an illustrious history of publishing pioneering and influential research articles across the entire range of the physical and mathematical sciences. These have included Maxwell"s electromagnetic theory, the Braggs" first account of X-ray crystallography, Dirac"s relativistic theory of the electron, and Watson and Crick"s detailed description of the structure of DNA.