bug in roots

[zimmermann6]

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| SAGE Version 3.1.4, Release Date: 2008-10-16                       |
| Type notebook() for the GUI, and license() for information.        |
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sage: R=PolynomialRing(ZZ, x)
sage: f=R(x^4+1)
sage: f.roots(GF(2))
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
...
ValueError: factorization of 0 not defined

Component: basic arithmetic

Issue created by migration from https://trac.sagemath.org/ticket/4328

[zimmermann6]

comment:1

I should have said it works with vanilla 3.1.4, thus it is most likely related to the recent patches for
GF(2)[x] I have applied to my 3.1.4 version.

[sagetrac-mabshoff]

comment:2

It works with my current 3.2.alpha0 merge tree:

mabshoff@sage:/scratch/mabshoff/release-cycle/sage-3.2.alpha0$ ./sage
----------------------------------------------------------------------
| SAGE Version 3.1.4, Release Date: 2008-10-16                       |
| Type notebook() for the GUI, and license() for information.        |
----------------------------------------------------------------------

sage: R=PolynomialRing(ZZ, x)
sage: sage: f=R(x^4+1)
sage: sage: f.roots(GF(2))
[(1, 4)]

I suspect the root cause could be #4302.

Cheers,

Michael

[malb]

comment:3

worksforme:

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| SAGE Version 3.1.3, Release Date: 2008-10-14                       |
| Type notebook() for the GUI, and license() for information.        |
----------------------------------------------------------------------
Loading SAGE library. Current Mercurial branch is: test
sage: R=PolynomialRing(ZZ, x)
sage: f=R(x^4+1)
sage: f.roots(GF(2))
[(1, 4)]

sage: P.<x> = PolynomialRing(GF(2))
sage: type(x) # check whether the patch is applied
<type 'sage.rings.polynomial.polynomial_gf2x.Polynomial_GF2X'>

Note that I updates #4302 recently.