JAVA arithmetic problem with double ?

If I try to work double precision numbers I get a unintelligible result, but what do I do wrong ?
Are there any inaccuracy in the JAVA double precision numbers arithmetic or what's the problem with this very simple example code ? How can I get correct result ?
Simple example code :
================
for (double i = 0; i < 10; i = i + 0.01)
System.out.println(i);
On the output :
===========
0.0
0.01
0.02
0.03
0.04
0.05
0.060000000000000005
0.07
0.08
0.09
0.09999999999999999
0.10999999999999999
0.11999999999999998
0.12999999999999998
0.13999999999999999
0.15
0.16
0.17
0.18000000000000002
0.19000000000000003
0.20000000000000004
0.21000000000000005
0.22000000000000006
0.23000000000000007
0.24000000000000007
0.25000000000000006
0.26000000000000006
0.2700000000000001
0.2800000000000001
0.2900000000000001
0.3000000000000001
0.3100000000000001
0.3200000000000001
0.3300000000000001
0.34000000000000014
0.35000000000000014
0.36000000000000015
0.37000000000000016
0.38000000000000017
0.3900000000000002
0.4000000000000002
0.4100000000000002
0.4200000000000002
0.4300000000000002
0.4400000000000002
0.45000000000000023
0.46000000000000024
0.47000000000000025
0.48000000000000026
0.49000000000000027
0.5000000000000002
0.5100000000000002
0.5200000000000002
0.5300000000000002
0.5400000000000003
0.5500000000000003
0.5600000000000003
0.5700000000000003
0.5800000000000003
0.5900000000000003
0.6000000000000003
0.6100000000000003
0.6200000000000003
0.6300000000000003
0.6400000000000003
0.6500000000000004
0.6600000000000004
0.6700000000000004
0.6800000000000004
0.6900000000000004
0.7000000000000004
0.7100000000000004
0.7200000000000004
0.7300000000000004
0.7400000000000004
0.7500000000000004
0.7600000000000005
0.7700000000000005
0.7800000000000005
0.7900000000000005
0.8000000000000005
0.8100000000000005
0.8200000000000005
0.8300000000000005
0.8400000000000005
0.8500000000000005
0.8600000000000005
0.8700000000000006
0.8800000000000006
0.8900000000000006
0.9000000000000006
0.9100000000000006
0.9200000000000006
0.9300000000000006
0.9400000000000006
0.9500000000000006
0.9600000000000006
0.9700000000000006
0.9800000000000006
0.9900000000000007
1.0000000000000007
1.0100000000000007
1.0200000000000007
1.0300000000000007
1.0400000000000007
1.0500000000000007
1.0600000000000007
1.0700000000000007
1.0800000000000007
1.0900000000000007
1.1000000000000008
1.1100000000000008
1.1200000000000008
1.1300000000000008
1.1400000000000008
1.1500000000000008
1.1600000000000008
1.1700000000000008
1.1800000000000008
1.1900000000000008
1.2000000000000008
1.2100000000000009
1.2200000000000009
1.2300000000000009
1.2400000000000009
1.2500000000000009
1.260000000000001
1.270000000000001
1.280000000000001
1.290000000000001
1.300000000000001
1.310000000000001
1.320000000000001
1.330000000000001
1.340000000000001
1.350000000000001
1.360000000000001
1.370000000000001
1.380000000000001
1.390000000000001
1.400000000000001
1.410000000000001
1.420000000000001
1.430000000000001
1.440000000000001
1.450000000000001
1.460000000000001
1.470000000000001
1.480000000000001
1.490000000000001
1.500000000000001
1.5100000000000011
1.5200000000000011
1.5300000000000011
1.5400000000000011
1.5500000000000012
1.5600000000000012
1.5700000000000012
1.5800000000000012
1.5900000000000012
1.6000000000000012
1.6100000000000012
1.6200000000000012
1.6300000000000012
1.6400000000000012
1.6500000000000012
1.6600000000000013
1.6700000000000013
1.6800000000000013
1.6900000000000013
1.7000000000000013
1.7100000000000013
1.7200000000000013
1.7300000000000013
1.7400000000000013
1.7500000000000013
1.7600000000000013
1.7700000000000014
1.7800000000000014
1.7900000000000014
1.8000000000000014
1.8100000000000014
1.8200000000000014
1.8300000000000014
1.8400000000000014
1.8500000000000014
1.8600000000000014
1.8700000000000014
1.8800000000000014
1.8900000000000015
1.9000000000000015
1.9100000000000015
1.9200000000000015
1.9300000000000015
1.9400000000000015
1.9500000000000015
1.9600000000000015
1.9700000000000015
1.9800000000000015
1.9900000000000015
2.0000000000000013
2.010000000000001
2.020000000000001
2.0300000000000007
2.0400000000000005
2.0500000000000003
Thanks for answerers !
Joseph

This result is entirely unsurprising, and the flaw lies in your program, not in Java.
Java represents numbers in 2's complement [SEM] form (read the Java Language Specification (JLS), according to agreed standards. When you specify a fractional number that appears to be nice and easy to work with, you are thinking in decimal notation, not binary, and you are giving it a number that cannot be precisely represented. It is a little like asking you to write down exactly what pi is (all its digits ;-)).
So the number you get is not precisely what you asked for (one very insignificant error). But then you compound it by adding an inaccurately represented number to an inaccurately represented number, and so on, until the bit errors combine to make a very inaccurate number.
The correct way to approach what you are trying to do would be to perform the addition using integers, and multiply each time you want to scale it to a double.
This has been asked many times - I would suggest you:
- Search the forums
- Check out the language spec
- or do a degree in CompSci :-)
A calculator is a little more accurate because it does not have to conform to agreed standards, and so can use special logic to minimise such errors. The average pocket calulator also works to a much lower level of accuracy (usu 8 digits), and therefore masks the errors to you. You'd find that you got the same effect if you played with it long enough.
Hope this helps

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*** 331,338 ****
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--- 331,337 ----
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*** 367,388 ****
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--- 366,371 ----
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+
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*** 1400,1405 ****
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               score_painter.draw_score(g, score);
               level_display.draw_level(g, level);
               explosion.draw_boom(g);
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Thanks in advance
Sebastian

This is a simple animation example quickly thrown together. I have two classes, an animation panel which is a JPanel subclass that overrides paintComponent and draws the animation, and a JApplet subclass that simply holds the animation panel in the applet's contentpane:
SimpleAnimationPanel.java
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.JPanel;
import javax.swing.Timer;
class SimpleAnimationPanel extends JPanel
    private static final int DELAY = 20;
    public static final int X_TRANSLATION = 2;
    public static final int Y_TRANSLATION = 2;
    private Point point = new Point(5, 32);
    private BufferedImage duke = null;
    private Timer timer = new Timer(DELAY, new TimerAction());
    public SimpleAnimationPanel()
        try
            // borrow an image from sun.com
            duke = ImageIO.read(new URL(
                    "http://java.sun.com/products/plugin/images/duke.wave.med.gif"));
        catch (MalformedURLException e)
            e.printStackTrace();
        catch (IOException e)
            e.printStackTrace();
        setPreferredSize(new Dimension(600, 400));
        timer.start();
    // do our drawing here in the paintComponent override
    @Override
    protected void paintComponent(Graphics g)
        super.paintComponent(g);
        if (duke != null)
            g.drawImage(duke, point.x, point.y, this);
    private class TimerAction implements ActionListener
        @Override
        public void actionPerformed(ActionEvent e)
            int x = point.x;
            int y = point.y;
            Dimension size = SimpleAnimationPanel.this.getSize();
            if (x > size.width)
                x = 0;
            else
                x += X_TRANSLATION;
            if (y > size.height)
                y = 0;
            else
                y += Y_TRANSLATION;
            point.setLocation(new Point(x, y)); // update the point
            SimpleAnimationPanel.this.repaint();
}AnimationApplet.java
import java.lang.reflect.InvocationTargetException;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class AnimationApplet extends JApplet
    public void init()
        try
            SwingUtilities.invokeAndWait(new Runnable()
                public void run()
                    // construct the panel
                    JPanel simpleAnimation = new SimpleAnimationPanel();
                    // put it in the contentPane of the JApplet
                    getContentPane().add(simpleAnimation);
                    setSize(simpleAnimation.getPreferredSize());
        catch (InterruptedException e)
            e.printStackTrace();
        catch (InvocationTargetException e)
            e.printStackTrace();
}Here's a 3rd bonus class that shows how to put the JPanel into a stand-alone program, a JFrame. It's very similar to doing it in the JApplet:
AnimationFrame.java
import javax.swing.JFrame;
public class AnimationFrame
    private static void createAndShowUI()
        JFrame frame = new JFrame("SimpleAnimationPanel");
        frame.getContentPane().add(new SimpleAnimationPanel());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    public static void main(String[] args)
        java.awt.EventQueue.invokeLater(new Runnable()
            public void run()
                createAndShowUI();
}Edited by: Encephalopathic on Mar 15, 2008 11:01 PM

Problem with double click in alv interactive report

Hello frnds,
        the problem is i am displaying basic list using grid display with pf-status and usercommand forms. My first column is checkbox, after selecting checkboxes if i click on the pf-status Button then in the internal table corresponding field is not getting updated with value 'X'. But once if i double click on the basic list after selecting the checkboxes the values are reflecting as X in the internal table . But my requirement is i want to get the values to be populated once i click on push button only ?
fcode i have used is &IC1( which is the fcode to trigger double event).Please help me out.
Thanks in advance.
subash.

hi ,
i had used like this .. it is working...
*&      Form USER_COMMAND
FORM USER_COMMAND USING R_UCOMM LIKE SY-UCOMM
                        R_SELFIELD TYPE SLIS_SELFIELD.
clear : v_flag.
CASE R_UCOMM.
    WHEN 'DATA'.
LOOP AT IT_TEMP.
     if it_temp-checkbox = 'X'.
          v_flag = 'X'.
          v_pernr1 = IT_TEMP-PERNR.
*--Get compensation data and populate final internal table
          refresh it_fin.
          CALL FUNCTION 'Z_HR_COMP_STATEMENT'
            EXPORTING
              PERNR = v_pernr1
              BEGDA = s_date-low
              ENDDA = s_date-high
            TABLES
              FINAL = it_fin.
          if not it_fin[] is initial.
            delete adjacent duplicates from it_fin comparing pernr.
            read table it_fin index 1.
            move-corresponding it_fin to it_final.
            append it_final.
            clear it_final.
          endif.
        endif.
     enddo.
ENDLOOP.
      if not v_flag is initial.
*------ display final data
        PERFORM final_display.
      else.
        message s000 with 'Select atleast one pernr'.
      endif.
endcase.
ENDFORM.                    "USER_COMMAND
regards,
venkat.

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I have a mid 2012 macbook pro 17", i recently installed Yosemite although it fixed my internet problem (connection dropping randomly) now i am having issues with opening apps and files. Double clicking on a file launches the corresponding app but does't open the file i just get and message stating the app is not open anymore if click the file again. Finder keyboard shorcuts such as command+Q don't work. Can't access some menu items such as "about this mac". Dragging a file into the dock icon launches the app but doesn't open the file either.
I have no idea what's causing this. anybody got a clue or having similar problems
Thank you

Same problem here. (Yosemite 10.0.1)
the mouse is a 'team scorpion g-reaver' http://teamscorpion.net/ts2014/g-reaver_1.html
It's work perfectly on the pc of my brother (he uses windows).
It's a clean install...
And has a funny fact... The Left Button was with this problem... So what I did? I changed the primary mouse button to the Right... Worked ok for almost 1~2 days... After that, the two buttons showed the double-click problem....
But, I repeat, the mouse works perfectly in the windows of my brother '-'

Java VM problems with dbassist

I downloaded jdk116_v5 from blackdown as instructed in the
installation manual. It's installed in /jdk116_v5 and I created
the link to /usr/local/jre also as instructed.
The installation went well until the end. It couldn't run the
dbassist. It spewed the message:
Unable to initialize threads: Cannot find class java/lang/thread
Could not create Java VM
The same message also pops up whenever I try running the
dbassist program.
The readme that came with jdk said that it does need a JAVA_HOME
and CLASSPATH. I have experimented with setting the JAVA_HOME
to /jdk116_v5 and CLASSPATH to /jdk116_v5 and also
to /jdk116_v5/lib and /jdk116_v5/lib/classes.zip but nothing
seems to solve the problem.
Does anyone have any suggestions? Unfortunately, (dare I say it?)
Java is not one of my strengths...
Thanks and Regards
Devin
null

I modified the dbassist script to add the
$JRE_DIR/lib/classes.zip to CLASSPATH
Got rid of the not finding the lang/thread class error. but now
get an exception
java.lang.NullPointerException
at
CheckerClass_base.CheckforNcharSets(CheckerClass_base.java:995)
at CheckerClass.initializeLanguage(CheckerClass.java:241)
at CheckerClass.DetectAll(CheckerClass.java:73)
at DBConfigInfo_base.<init>(DBConfigInfo_base.java:901)
at DBConfigInfo.<init>(DBConfigInfo.java:44)
at DBCreateWizard.<init>(DBCreateWizard.java:421)
at DBCreateWizard.main(DBCreateWizard.java:1082)
Devin Smith (guest) wrote:
: I downloaded jdk116_v5 from blackdown as instructed in the
: installation manual. It's installed in /jdk116_v5 and I created
: the link to /usr/local/jre also as instructed.
: The installation went well until the end. It couldn't run the
: dbassist. It spewed the message:
: Unable to initialize threads: Cannot find class
java/lang/thread
: Could not create Java VM
: The same message also pops up whenever I try running the
: dbassist program.
: The readme that came with jdk said that it does need a
JAVA_HOME
: and CLASSPATH. I have experimented with setting the JAVA_HOME
: to /jdk116_v5 and CLASSPATH to /jdk116_v5 and also
: to /jdk116_v5/lib and /jdk116_v5/lib/classes.zip but nothing
: seems to solve the problem.
: Does anyone have any suggestions? Unfortunately, (dare I say
it?)
: Java is not one of my strengths...
: Thanks and Regards
: Devin
null

HttpServletRequesr.getParameter : Problem with double quotes

Hi,
I am having a problem in accessing "POST" parameters which have "quotes" in it. For example,
If the post parameter named param contains Hello "(hw)" World, the getParameter returns Hello instead of Hello "(hw)" World.
I'm not sure if this is related to encoding. Encoding seem to be ISO-8859-1 (got from getCharacterEncoding).
Any clue of the problem ?

How do you send the post parameters. Do you send them usign a html from or are you sending them programaticaly. In that case make sure the keys and values are URL encoded with UTF-8

Problem With Double

I'm executing the code abouve, but I found an error:
double d4 = 19.64 + .51;
System.out.println(">>d4:" + d4);
[out] >>d4:20.150000000000002 // erro

This tech tip article explains what you're seeing:
http://java.sun.com/developer/JDCTechTips/2003/tt0204.html#2

Java installation problem with E60

did anyone experience this?
i can't install any java file (.jar or .jad) to my E60. including opera mini..
any ideas?
i tried to install both to memory card or to phone memory.
while the installation bar is in progress suddenly an alert says "unable to install"...
.sisx files works fine..
please help.
Heni

I had same problem. Here's where...
http://java.sun.com/j2se/1.4.2/system-configurations.html
Supported System Configurations
JavaTM 2 Platform, Standard Edition
Version 1.4.2
These configurations apply to both the Java 2 SDK and Java 2 Runtime Environment (J2RE).
IA32 Windows
System Requirements
32-bit: SDK J2RE
Windows 98 (1st & 2nd Editions) Windows Active & Classic Desktop

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