bugGNU Octave - Bugs: bug #29333, something went wrong while...

 
 

bug #29333: something went wrong while calculcation of mod

Submitted by:  None
Submitted on:  Thu 25 Mar 2010 12:17:10 PM UTC  
 
Category: InterpreterSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Incorrect Result
Status: FixedAssigned to: Jaroslav Hajek <highegg>
Originator Name: David MonichiOriginator Email: -unavailable-
Open/Closed: ClosedRelease: 3.2.4
Operating System: GNU/Linux

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Wed 31 Mar 2010 06:09:18 AM UTC, comment #1:

In development version, mod is now handled by fmod (+ manipulation afterwards), so this should be fixed as long as fmod provides accurate results. Note, however, that 2^70 is a floating-point number by default and so working with it is inaccurate. Use int64 and uint64 for big integers. If these aren't enough and you need true bignums, you probably need something else than Octave.

Jaroslav Hajek <highegg>In charge of this item.
Thu 25 Mar 2010 12:17:10 PM UTC, original submission:

Calculcating some cryptography stuff I got following result today:

octave:1> mod(2^(35*2),561)
ans = 131072
octave:2>

At least I would have expected to get some error message like NaN, Inf, ... so I know what's going on.

Didn't have to possibility to check it with a newer version, sorry

cheers

/david

Anonymous

 

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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Wed 31 Mar 2010 06:09:51 AM UTChigheggStatusNone=>Fixed
      Open/ClosedOpen=>Closed
    Wed 31 Mar 2010 06:09:18 AM UTChigheggAssigned toNone=>highegg

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