From owner-freebsd-java  Sun Jul 11  3:26:11 1999
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To: freebsd-java@FreeBSD.ORG
Subject: Re: strange java calculation errors
In-reply-to: Your message of "Fri, 09 Jul 1999 16:04:32 CST."
	<199907092204.QAA09955@mt.sri.com>
Date: Sun, 11 Jul 1999 19:22:57 +0900
From: SHUDO Kazuyuki <shudoh@muraoka.info.waseda.ac.jp>
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> > > > >I use the latest jdk1.1.8_ELF.V99-6-3.tar.gz with applied net-patch.
> > > > >On a few-weeks-old 3.2-STABLE.
> > > > >I have strange arithmetic errors.

> > Ok, I set up a sample program. I think it needs to be an awt-application.
> > I don't get any errors without setVisible(), but with a visible frame
> > I get errors every few seconds. It has to be a Thread, too, I think.

> > Martin
> >
> > //BugTest.java ----------------------------------------------

I could simplify this code a bit.
Math.pow(...) returns a strange value occasionally.
Moving a mouse pointer on the frame seems to
increase the frequency of errors.

Kazuyuki SHUDO				Happy Hacking!
  Muraoka Lab., Grad. School of Sci. & Eng., Waseda Univ.

==========
import java.awt.*;
import java.util.Random;

public class BugTest extends Frame implements Runnable {
  public BugTest(){
    setSize(100,100);
    setVisible(true);
  }

  public void run(){
    double base, pow;

    Random random = new Random();

    while (true){
      base =  random.nextDouble() * 10.0;
      pow = Math.pow(base, 3.9);

      if (pow < 1.0e-200) {
	System.out.println();
	System.out.println("base: " + base +
	  " (0x" + Long.toHexString(Double.doubleToLongBits(base)) + ")");
	System.out.println("pow: " + pow +
	  " (0x" + Long.toHexString(Double.doubleToLongBits(pow)) + ")");
      }
    }
  }

  public static void main(String args[]){
    BugTest bug = new BugTest();
    Thread bugThread = new Thread(bug);
    bugThread.setPriority(Thread.MIN_PRIORITY);
    bugThread.start();
  }
}


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