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Posted to issues@commons.apache.org by "Alex (JIRA)" <ji...@apache.org> on 2012/07/24 22:58:35 UTC
[jira] [Updated] (MATH-832) Brent solver calculates incorrect root
(namley Double.MAX_VALUE)
[ https://issues.apache.org/jira/browse/MATH-832?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Alex updated MATH-832:
----------------------
Description:
Wolfram-Alpha-Solution:
http://www.wolframalpha.com/input/?i=min+100*sqrt%28x%29%2B1000000%2Fx%2B10000%2Fsqrt%28x%29+with+x%3E0
Java-Input:{code:title=Test.java|borderStyle=solid}
int startValue1 = 100 + 1000000 + 10000;
int startValue2 = 100;
System.out.println(
(new BrentSolver()).solve(Integer.MAX_VALUE, new UnivariateFunction() {
@Override
public double value(double x) {
return 100/(2*Math.sqrt(x)) - 1000000/Math.pow(x,2) - 10000/(2*Math.pow(x,(double) 3/2));
}
}, 1/Double.MAX_VALUE, Double.MAX_VALUE, startValue1)
);
System.out.println(
(new BrentSolver()).solve(Integer.MAX_VALUE, new UnivariateFunction() {
@Override
public double value(double x) {
return 100/(2*Math.sqrt(x)) - 1000000/Math.pow(x,2) - 10000/(2*Math.pow(x,(double) 3/2));
}
}, 1/Double.MAX_VALUE, Double.MAX_VALUE, startValue2)
);{code}
Java-Output:{code:borderStyle=solid}
804.9355821866686
1.7976931348623157E308 (= Double.MAX_VALUE){code}
was:
Wolfram-Alpha-Solution:
http://www.wolframalpha.com/input/?i=min+100*sqrt%28x%29%2B1000000%2Fx%2B10000%2Fsqrt%28x%29+with+x%3E0
Java-Input:{code:title=Test.java|borderStyle=solid}
int startValue1 = 100 + 1000000 + 10000;
int startValue2 = 100;
System.out.println(
(new BrentSolver()).solve(Integer.MAX_VALUE, new UnivariateFunction() {
@Override
public double value(double x) {
return 100/(2*Math.sqrt(x)) - 1000000/Math.pow(x,2) - 10000/(2*Math.pow(x,(double) 3/2));
}
}, 1/Double.MAX_VALUE, Double.MAX_VALUE, startValue1)
);
System.out.println(
(new BrentSolver()).solve(Integer.MAX_VALUE, new UnivariateFunction() {
@Override
public double value(double x) {
return 100/(2*Math.sqrt(x)) - 1000000/Math.pow(x,2) - 10000/(2*Math.pow(x,(double) 3/2));
}
}, 1/Double.MAX_VALUE, Double.MAX_VALUE, startValue2)
);{code}
Java-Output:{code:title=Test.java|borderStyle=solid}
804.9355821866686
1.7976931348623157E308 (= Double.MAX_VALUE){code}
> Brent solver calculates incorrect root (namley Double.MAX_VALUE)
> ----------------------------------------------------------------
>
> Key: MATH-832
> URL: https://issues.apache.org/jira/browse/MATH-832
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 3.0
> Environment: Netbeans 7.1.2
> Reporter: Alex
> Original Estimate: 0.75h
> Remaining Estimate: 0.75h
>
> Wolfram-Alpha-Solution:
> http://www.wolframalpha.com/input/?i=min+100*sqrt%28x%29%2B1000000%2Fx%2B10000%2Fsqrt%28x%29+with+x%3E0
> Java-Input:{code:title=Test.java|borderStyle=solid}
> int startValue1 = 100 + 1000000 + 10000;
> int startValue2 = 100;
> System.out.println(
> (new BrentSolver()).solve(Integer.MAX_VALUE, new UnivariateFunction() {
> @Override
> public double value(double x) {
> return 100/(2*Math.sqrt(x)) - 1000000/Math.pow(x,2) - 10000/(2*Math.pow(x,(double) 3/2));
> }
> }, 1/Double.MAX_VALUE, Double.MAX_VALUE, startValue1)
> );
> System.out.println(
> (new BrentSolver()).solve(Integer.MAX_VALUE, new UnivariateFunction() {
> @Override
> public double value(double x) {
> return 100/(2*Math.sqrt(x)) - 1000000/Math.pow(x,2) - 10000/(2*Math.pow(x,(double) 3/2));
> }
> }, 1/Double.MAX_VALUE, Double.MAX_VALUE, startValue2)
> );{code}
> Java-Output:{code:borderStyle=solid}
> 804.9355821866686
> 1.7976931348623157E308 (= Double.MAX_VALUE){code}
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