bugGNU Octave - Bugs: bug #60800, [octave forge] (communications)...

 
 

bug #60800: [octave forge] (communications) rsenc() returns incorrect result with shortened messages

Submitter:  None
Submitted:  Sun 20 Jun 2021 12:46:45 AM UTC
   
 
Category:  Octave Package Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  None Assigned to:  None
Originator Name:  Matt Hostetter Originator Email:  -email is unavailable-
Open/Closed:  * Open Release:  * 5.2.0
Operating System:  * GNU/Linux Fixed Release:  None
Planned Release:  None
* Mandatory Fields

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Fri 31 Jan 2025 06:58:33 PM UTC, comment #1: 

I confirm this incorrect behavior. A fix would be appreciated.

Nir Krakauer <nir_krakauer>
Sun 20 Jun 2021 12:46:45 AM UTC, original submission:  

Reed-Solomon encoding with shortened codes seems to not be working.

The generator polynomial for RS(15, 9) is g(x) = x^6 + 7x^5 + 9x^4 + 3x^3 + 12x^2 + 10x + 12. Encoding the message m(x) = 1 should result in the codeword c(x) = m(x)g(x) = g(x), as seen in the third line. However, when encoding the shortened message [0,0,0,0,1] the incorrect codeword is produced.


octave:165> rsgenpoly(15, 9)
ans =
GF(2^4) array. Primitive Polynomial = D^4+D+1 (decimal 19)

Array elements =

    1    7    9    3   12   10   12

octave:166> rsenc(gf([0,0,0,0,1], 4), 15-4, 9-4, 'end')
ans =
GF(2^4) array. Primitive Polynomial = D^4+D+1 (decimal 19)

Array elements =

    0    0    0    0    1    7    1   12    8   10   12

octave:167> rsenc(gf([0,0,0,0,0,0,0,0,1], 4), 15, 9, 'end')
ans =
GF(2^4) array. Primitive Polynomial = D^4+D+1 (decimal 19)

Array elements =

    0    0    0    0    0    0    0    0    1    7    9    3   12   10   12


Anonymous

 

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    History

    Follow 2 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2021-06-20 siko1056 CategoryLibraries Octave Package
        Summary(communications) rsenc() returns incorrect result with shortened messages [octave forge] (communications) rsenc() returns incorrect result with shortened messages

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