Result of multiplying and equals for complex numbers is wrong
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Key: MATH-221
URL: https://issues.apache.org/jira/browse/MATH-221
Project: Commons Math
Issue Type: Bug
Affects Versions: 1.2
Environment: OS: Debian lenny
IDE: Version: 3.4.0; Build id: I20080617-2000
java.runtime.version=1.6.0_04-b12
java.vendor.url=http://java.sun.com/
Reporter: Dieter Roth
Priority: Minor
Hi.
The bug relates on complex numbers.
The methods "multiply" and "equals" of the class Complex are involved.
Mathematoc background: (0,i) * (-1,0i) = (0,-i).
Little java program + output that shows the bug:
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import org.apache.commons.math.complex.*;
public class TestProg {
public static void main(String[] args) {
ComplexFormat f = new ComplexFormat();
Complex c1 = new Complex(0,1);
Complex c2 = new Complex(-1,0);
Complex res = c1.multiply(c2);
Complex comp = new Complex(0,-1);
System.out.println("res: "+f.format(res));
System.out.println("comp: "+f.format(comp));
System.out.println("res=comp: "+res.equals(comp));
}
}
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res: -0 - 1i
comp: 0 - 1i
res=comp: false
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I think the problem could be "multiply" method that gives (-0,-1i) instead of
(0,-1i).
Or if you think thats right, the equals method has to be modified.
Good Luck
Dieter
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