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Posted to c-dev@axis.apache.org by "Fred Preston (JIRA)" <ax...@ws.apache.org> on 2005/09/28 12:51:47 UTC

[jira] Created: (AXISCPP-838) The serialisation of 555.555 as a float produces a value of 555.554993 on the wire.

The serialisation of 555.555 as a float produces a value of 555.554993 on the wire.
-----------------------------------------------------------------------------------

         Key: AXISCPP-838
         URL: http://issues.apache.org/jira/browse/AXISCPP-838
     Project: Axis-C++
        Type: Bug
  Components: Serialization  
 Environment: n/a
    Reporter: Fred Preston


Using the UnitTest_XSD_float test.  If you change the code as follows:-

Was
[40]// Test non-nillable element
[41]	    xsd__float result = ws->asNonNillableElement((xsd__float)35.353588);

Now
[40]// Test non-nillable element
[41]	    xsd__float result = ws->asNonNillableElement((xsd__float)555.555);

Then on the wire you get:-
<nonNillableElement>555.554993</nonNillableElement>


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Re: [jira] Created: (AXISCPP-838) The serialisation of 555.555 as a float produces a value of 555.554993 on the wire.

Posted by Fred Preston <PR...@uk.ibm.com>.

Hi Manohar,
        This is obviously to do with rounding errors in the floating point 
conversion.  There will always be some numbers that will not interpret 
exactly to a given length because of the way that the number is held 
internally.  I would need to work out what 555.555 looked like as a 
floating point number, but I'm sure it will not be able to be represented 
exactly within the limits of a float type.  Thus a certain amount of 
accuracy is lost.  It could be that we are compounding errors somewhere or 
we need to look at how we store and recover numbers.  We may also need to 
look at how much accuracy is 'actually' available in floating point 
numbers.

Regards,

Fred Preston.





Manohar K Chintala <cm...@in.ibm.com>
30/09/2005 09:11
Please respond to "Apache AXIS C Developers List"
 
        To:     "Apache AXIS C Developers List" <ax...@ws.apache.org>
        cc: 
        Subject:        Re: [jira] Created: (AXISCPP-838) The 
serialisation of 555.555 as a float produces a value of 555.554993 on the 
wire.

 


I've observed that when result is displayed using "%.5f" this problem
occurs. If result is displayed using "%.3f" the output is 555.555, and for
"%.4f" the output is proper 555.5550. Also, this problem happens with 
1,5,7
and 9 numbers when only. i.e. when the values given like  555.111 ,
555.555, 555.777 and 555.999 this serialization problem occurs and for
other numbers it works fine.

Regards
Manohar



 
             "Fred Preston 
             (JIRA)" 
             <axis-c-dev@ws.ap                                          To 

             ache.org>                 axis-c-dev@ws.apache.org 
                                                                        cc 

             09/28/2005 04:21 
             PM                                                    Subject 

                                       [jira] Created: (AXISCPP-838) The 
                                       serialisation of 555.555 as a float 

             Please respond to         produces a value of 555.554993 on 
              "Apache AXIS C           the wire. 
             Developers List" 
 
 
 
 
 




The serialisation of 555.555 as a float produces a value of 555.554993 on
the wire.
-----------------------------------------------------------------------------------


         Key: AXISCPP-838
         URL: http://issues.apache.org/jira/browse/AXISCPP-838
     Project: Axis-C++
        Type: Bug
  Components: Serialization
 Environment: n/a
    Reporter: Fred Preston


Using the UnitTest_XSD_float test.  If you change the code as follows:-

Was
[40]// Test non-nillable element
[41]             xsd__float result =
ws->asNonNillableElement((xsd__float)35.353588);

Now
[40]// Test non-nillable element
[41]             xsd__float result =
ws->asNonNillableElement((xsd__float)555.555);

Then on the wire you get:-
<nonNillableElement>555.554993</nonNillableElement>


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