bugGNU Octave - Bugs: bug #40647, Matrix addition error

 
 

bug #40647: Matrix addition error

Submitted by:  None
Submitted on:  Wed 20 Nov 2013 03:15:56 PM UTC  
 
Category: Octave FunctionSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Incorrect Result
Status: InvalidAssigned to: None
Originator Name: MartinOriginator Email: -unavailable-
Open/Closed: ClosedRelease: 3.6.4
Operating System: GNU/Linux

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Thu 21 Nov 2013 09:13:52 PM UTC, comment #2:

http://wiki.octave.org/FAQ#Why_is_this_floating_point_computation_wrong.3F

Jordi GutiƩrrez Hermoso <jordigh>
Project Administrator
Wed 20 Nov 2013 03:47:55 PM UTC, comment #1:

This is a simple case of machine precision overrun. Please understand that numerical values in Octave are double-precision floating point by default, which limits the range of significant digits that can be represented.

Mike Miller <mtmiller>
Project Administrator
Wed 20 Nov 2013 03:15:56 PM UTC, original submission:

octave:64> f
f =

0 0

octave:65> d
d =

1.0000e-12 1.0000e-19

octave:66> e
e =

1 1

octave:67> e+d-e
ans =

1.0001e-12 0.0000e+00

octave:68> f+d-f
ans =

1.0000e-12 1.0000e-19

Anonymous

 

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    Follow 2 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Wed 20 Nov 2013 03:47:55 PM UTCmtmillerStatusNone=>Invalid
      Open/ClosedOpen=>Closed

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