Opened 10 years ago

Closed 10 years ago

#12928 closed defect (duplicate)

critical bug in multivariate polynomial factorization over GF(2)

Reported by: Paul Zimmermann Owned by: tbd
Priority: critical Milestone: sage-duplicate/invalid/wontfix
Component: factorization Keywords:
Cc: Martin Albrecht Merged in:
Authors: Reviewers: Jeroen Demeyer
Report Upstream: Fixed upstream, in a later stable release. Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Status badges

Description

consider the following (both with Sage 4.8 and Sage 5.0.beta13 without proof=False):

sage: R.<x,y>=GF(2)[]
sage: factor(x^6 + y^6 + x^5 + x^3 + x + 1,proof=False)
x^6 + y^6 + x^5 + x^3 + x + 1
sage: (x^4+y^2*x^2+x^2+y^2*x+y^4+y^2+1)*(x^2+x+y^2+1)     
x^6 + y^6 + x^5 + x^3 + x + 1

This seems to be a bug in Singular factorization. I set the priority to "critical" since this is really a very basic routine.

Paul

Change History (10)

comment:1 Changed 10 years ago by Paul Zimmermann

Cc: Martin Albrecht added

comment:2 Changed 10 years ago by Paul Zimmermann

here is another example:

sage: R.<x,t> = GF(2)[]
sage: f=x^6 + (t^5 + t^2)*x + t^5 + t^4 + t^3 + 1
sage: factor(f,proof=False)                      
x^6 + x*t^5 + t^5 + t^4 + x*t^2 + t^3 + 1
sage: f % (x+t+1)
0

Note that the factorization algorithm seems not to be deterministic, thus some times the factorization is correct.

Paul

comment:3 Changed 10 years ago by Paul Zimmermann

Note that for the example given in the description, the "bug" seems to be deterministic.

Paul

comment:4 Changed 10 years ago by Martin Albrecht

Hi, can you guys report this upstream? I am travelling this week.

comment:5 Changed 10 years ago by Paul Zimmermann

Report Upstream: N/AReported upstream. Little or no feedback.

comment:6 Changed 10 years ago by Paul Zimmermann

Report Upstream: Reported upstream. Little or no feedback.Fixed upstream, in a later stable release.

the bug is fixed upstream. I have asked in which release the patch will be.

Paul

comment:7 Changed 10 years ago by Paul Zimmermann

upstream says it is fixed in 3-1-4-4.

Paul

comment:8 Changed 10 years ago by Jeroen Demeyer

Milestone: sage-5.3sage-duplicate/invalid/wontfix
Reviewers: Jeroen Demeyer
Status: newneeds_review

Fixed by #13237.

comment:9 Changed 10 years ago by Jeroen Demeyer

Status: needs_reviewpositive_review

comment:10 Changed 10 years ago by Jeroen Demeyer

Resolution: duplicate
Status: positive_reviewclosed
Note: See TracTickets for help on using tickets.