{"title":"Explicit solutions of Genz test integrals","authors":"Vesa Kaarnioja","doi":"10.1016/j.aml.2024.109444","DOIUrl":null,"url":null,"abstract":"<div><div>A collection of test integrals introduced by Genz (1984) has remained popular to this day for assessing the robustness of high-dimensional numerical integration algorithms. However, the explicit solutions to these integrals do not appear to be readily available in the existing literature: typically the true values of the test integrals are simply approximated using “overkill” numerical solutions. In this paper, analytic solutions are presented for the Genz test integrals <span><span><span><math><mrow><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>⋯</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>cos</mo><mrow><mo>(</mo><mrow><mn>2</mn><mi>π</mi><msub><mrow><mi>w</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>+</mo><munderover><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow><mo>)</mo></mrow><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>⋯</mo><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>d</mi></mrow></msup><mo>cos</mo><mrow><mo>(</mo><mrow><mn>2</mn><mi>π</mi><msub><mrow><mi>w</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>+</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><munderover><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow><mo>)</mo></mrow><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><mfrac><mrow><mo>sin</mo><mrow><mo>(</mo><mfrac><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow><mrow><mn>2</mn></mrow></mfrac><mo>)</mo></mrow></mrow><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow></mfrac><mo>,</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>⋯</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><mfrac><mrow><mn>1</mn></mrow><mrow><msubsup><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msubsup><mo>+</mo><msup><mrow><mrow><mo>(</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>−</mo><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>⋯</mo><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><mrow><mo>(</mo><mrow><mo>arctan</mo><mrow><mo>(</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow><mo>+</mo><mo>arctan</mo><mrow><mo>(</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>−</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow></mrow><mo>)</mo></mrow><mo>,</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>⋯</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><msup><mrow><mrow><mo>(</mo><mrow><mn>1</mn><mo>+</mo><munderover><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow><mo>)</mo></mrow></mrow><mrow><mo>−</mo><mrow><mo>(</mo><mi>d</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow></mrow></msup><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>⋯</mo><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mi>d</mi><mo>!</mo><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow></mfrac><munder><mrow><mo>∑</mo></mrow><mrow><mi>u</mi><mo>⊆</mo><mrow><mo>{</mo><msub><mrow><mi>c</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>}</mo></mrow></mrow></munder><mfrac><mrow><msup><mrow><mrow><mo>(</mo><mo>−</mo><mn>1</mn><mo>)</mo></mrow></mrow><mrow><mi>#</mi><mi>u</mi></mrow></msup></mrow><mrow><mn>1</mn><mo>+</mo><munder><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>∈</mo><mi>u</mi></mrow></munder><mi>i</mi></mrow></mfrac><mo>,</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>⋯</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>exp</mo><mrow><mo>(</mo><mrow><mo>−</mo><munderover><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msubsup><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow><mrow><mn>2</mn></mrow></msubsup><msup><mrow><mrow><mo>(</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>−</mo><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow></mrow><mrow><mn>2</mn></mrow></msup></mrow><mo>)</mo></mrow><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>⋯</mo><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mfrac><mrow><msup><mrow><mi>π</mi></mrow><mrow><mi>d</mi><mo>/</mo><mn>2</mn></mrow></msup></mrow><mrow><msup><mrow><mn>2</mn></mrow><mrow><mi>d</mi></mrow></msup></mrow></mfrac><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><mfrac><mrow><mi>erf</mi><mrow><mo>(</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow><mo>+</mo><mi>erf</mi><mrow><mo>(</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>−</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow></mrow><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow></mfrac><mo>,</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>⋯</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>exp</mo><mrow><mo>(</mo><mrow><mo>−</mo><munderover><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><mrow><mo>|</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>−</mo><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>|</mo></mrow></mrow><mo>)</mo></mrow><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>⋯</mo><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><mfrac><mrow><mo>exp</mo><mrow><mo>(</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>−</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow><mo>−</mo><mo>exp</mo><mrow><mo>(</mo><mo>−</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow></mrow><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow></mfrac><mo>,</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><msub><mrow><mi>w</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></munderover><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><msub><mrow><mi>w</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></munderover><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>⋯</mo><munderover><mrow><mo>∫</mo></mrow><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow></munderover><mo>exp</mo><mrow><mo>(</mo><mrow><munderover><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow><mo>)</mo></mrow><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>⋯</mo><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow></msub><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msub><mspace></mspace><mi>d</mi><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mn>2</mn></mrow></munderover><mrow><mo>(</mo><mo>exp</mo><mrow><mo>(</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow><mo>−</mo><mn>1</mn><mo>)</mo></mrow><mfrac><mrow><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>3</mn></mrow><mrow><mi>d</mi></mrow></munderover><mrow><mo>(</mo><mo>exp</mo><mrow><mo>(</mo><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow><mo>−</mo><mn>1</mn><mo>)</mo></mrow></mrow><mrow><munderover><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>d</mi></mrow></munderover><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow></mfrac><mo>,</mo></mrow></math></span></span></span> where <span><math><mrow><mi>d</mi><mo>∈</mo><msub><mrow><mi>Z</mi></mrow><mrow><mo>+</mo></mrow></msub></mrow></math></span>, <span><math><mrow><mn>0</mn><mo><</mo><msub><mrow><mi>w</mi></mrow><mrow><mi>i</mi></mrow></msub><mo><</mo><mn>1</mn></mrow></math></span>, and <span><math><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>∈</mo><msub><mrow><mi>R</mi></mrow><mrow><mo>+</mo></mrow></msub></mrow></math></span> for all <span><math><mrow><mi>i</mi><mo>∈</mo><mrow><mo>{</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mi>d</mi><mo>}</mo></mrow></mrow></math></span>.</div></div>","PeriodicalId":55497,"journal":{"name":"Applied Mathematics Letters","volume":"163 ","pages":"Article 109444"},"PeriodicalIF":2.9000,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Mathematics Letters","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0893965924004646","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
A collection of test integrals introduced by Genz (1984) has remained popular to this day for assessing the robustness of high-dimensional numerical integration algorithms. However, the explicit solutions to these integrals do not appear to be readily available in the existing literature: typically the true values of the test integrals are simply approximated using “overkill” numerical solutions. In this paper, analytic solutions are presented for the Genz test integrals where , , and for all .
期刊介绍:
The purpose of Applied Mathematics Letters is to provide a means of rapid publication for important but brief applied mathematical papers. The brief descriptions of any work involving a novel application or utilization of mathematics, or a development in the methodology of applied mathematics is a potential contribution for this journal. This journal''s focus is on applied mathematics topics based on differential equations and linear algebra. Priority will be given to submissions that are likely to appeal to a wide audience.