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From "Phil Steitz (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MATH-464) LegendreGaussIntegrator ignores defaultMaximalIterationCount and does 38 million iterations
Date Thu, 11 Aug 2011 20:36:27 GMT

    [ https://issues.apache.org/jira/browse/MATH-464?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13083502#comment-13083502
] 

Phil Steitz commented on MATH-464:
----------------------------------

+1 for your suggestion, Luc.  Lets try to get this into 3.0.

> LegendreGaussIntegrator ignores defaultMaximalIterationCount and does 38 million iterations
> -------------------------------------------------------------------------------------------
>
>                 Key: MATH-464
>                 URL: https://issues.apache.org/jira/browse/MATH-464
>             Project: Commons Math
>          Issue Type: Bug
>    Affects Versions: 2.1
>            Reporter: Michael Borcherds
>            Priority: Critical
>             Fix For: 3.0
>
>   Original Estimate: 3h
>  Remaining Estimate: 3h
>
> The following code results in count = 37801710 which is effectively an infinite loop
for typical functions we are using
> (in GeoGebra)
> The argument defaultMaximalIterationCount = 100 is being ignored
> This is the version we are using:
> http://www.geogebra.org/trac/browser/trunk/geogebra/org/apache/commons/math/analysis/integration/LegendreGaussIntegrator.java
>     	LegendreGaussIntegrator gauss = new LegendreGaussIntegrator(5, 100);
>     
> 	try {
> 		double result = gauss.integrate(new testFun(), -10, 0.32462367623786328);
> 	} catch (Exception ee) {
> 		ee.printStackTrace();
> 	}
> class testFun implements UnivariateRealFunction {
>     public double value(double x) throws FunctionEvaluationException {
>     	count ++;
>         if (x>=0 && x<=5) return 0.2; else return 0;
>     }
> }

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