#10369: Yet another bug in factorization over number fields
-----------------------------+----------------------------------------------
Reporter: lftabera | Owner: tbd
Type: defect | Status: new
Priority: critical | Milestone: sage-4.6.2
Component: factorization | Keywords: factorization, number fields
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
-----------------------------+----------------------------------------------
I have found several issues factoring polynomials over number fields. This
time pari seems to work ok, so it is not related to #10279
{{{
sage: N.<a>=NumberField(x^6+x^5+x^4+x^3+x^2+x+1)
sage: K.<t>=N[]
sage: l = (-1/7*a^5 - 1/7*a^4 - 1/7*a^3 - 1/7*a^2 - 2/7*a - 1/7)*t^10 +
(4/7*a^5 - 2/7*a^4 - 2/7*a^3 - 2/7*a^2 - 2/7*a - 6/7)*t^9 + (90/49*a^5 +
152/49*a^4 + 18/49*a^3 + 24/49*a^2 + 30/49*a + 36/49)*t^8 + (-10/49*a^5 +
10/7*a^4 + 198/49*a^3 - 102/49*a^2 - 60/49*a - 26/49)*t^7 + (40/49*a^5 +
45/49*a^4 + 60/49*a^3 + 277/49*a^2 - 204/49*a - 78/49)*t^6 + (90/49*a^5 +
110/49*a^4 + 2*a^3 + 80/49*a^2 + 46/7*a - 30/7)*t^5 + (30/7*a^5 +
260/49*a^4 + 250/49*a^3 + 232/49*a^2 + 32/7*a + 8)*t^4 + (-184/49*a^5 -
58/49*a^4 - 52/49*a^3 - 66/49*a^2 - 72/49*a - 72/49)*t^3 + (18/49*a^5 -
32/49*a^4 + 10/49*a^3 + 4/49*a^2)*t^2 + (2/49*a^4 - 4/49*a^3 + 2/49*a^2)*t
sage: factor(l)
}}}
Depending on the execution I get two answers
wrong answer:
{{{
(-1/7*a^5 - 1/7*a^4 - 1/7*a^3 - 1/7*a^2 - 2/7*a - 1/7) * t^4 * (t^6 +
(-19/7*a^5 - 17/7*a^4 - 15/7*a^3 - 13/7*a^2 - 11/7*a - 9/7)*t^5 + (2*a^5 -
10/7*a^4 - 16/7*a^3 + 10/7*a^2 - 2/7*a + 18/7)*t^4 + (-40/7*a^5 - 8/7*a^4
- 40/7*a^3 - 48/7*a^2 - 32/7)*t^3 + (26/7*a^5 - 6/7*a^4 + 26/7*a^3 -
6/7*a^2 - 4/7*a + 34/7)*t^2 + (-20/7*a^5 - 4/7*a^4 - 20/7*a^3 - 4/7*a^2 -
20/7*a - 16/7)*t + 2/7*a^5 - 2/7*a^4 + 2/7*a^3 - 2/7*a^2 + 2/7*a - 2/7)
}}}
solution that looks right:
{{{
(-1/7*a^5 - 1/7*a^4 - 1/7*a^3 - 1/7*a^2 - 2/7*a - 1/7) * t * (t - a^5 -
a^4 - a^3 - a^2 - a - 1)^4 * (t^5 + (-12/7*a^5 - 10/7*a^4 - 8/7*a^3 -
6/7*a^2 - 4/7*a - 2/7)*t^4 + (12/7*a^5 - 8/7*a^3 + 16/7*a^2 + 2/7*a +
20/7)*t^3 + (-20/7*a^5 - 20/7*a^3 - 20/7*a^2 + 4/7*a - 2)*t^2 + (12/7*a^5
+ 12/7*a^3 + 2/7*a + 16/7)*t - 4/7*a^5 - 4/7*a^3 - 4/7*a - 2/7)
}}}
With pari I only get the second answer, so it looks like a sage problem.
Next example is different:
{{{
sage: l2 = (-1/7*a^5 - 1/7*a^4 - 1/7*a^3 - 1/7*a^2 - 2/7*a - 1/7)*t^10 +
(4/7*a^5 - 2/7*a^4 - 2/7*a^3 - 2/7*a^2 - 2/7*a - 6/7)*t^9 + (90/49*a^5 +
152/49*a^4 + 18/49*a^3 + 24/49*a^2 + 30/49*a + 36/49)*t^8 + (-10/49*a^5 +
10/7*a^4 + 198/49*a^3 - 102/49*a^2 - 60/49*a - 26/49)*t^7 + (40/49*a^5 +
45/49*a^4 + 60/49*a^3 + 277/49*a^2 - 204/49*a - 78/49)*t^6 + (90/49*a^5 +
110/49*a^4 + 2*a^3 + 80/49*a^2 + 46/7*a - 30/7)*t^5 + (30/7*a^5 +
260/49*a^4 + 250/49*a^3 + 232/49*a^2 + 32/7*a + 8)*t^4 + (-184/49*a^5 -
58/49*a^4 - 52/49*a^3 - 66/49*a^2 - 72/49*a - 72/49)*t^3 + (18/49*a^5 -
32/49*a^4 + 10/49*a^3 + 4/49*a^2)*t^2 + (2/49*a^4 - 4/49*a^3 + 2/49*a^2)*t
}}}
The pari released with sage computes the factorization without problems,
but trying to compute the factorization with sage the program starts to
eat all available ram and you have to kill the program.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10369>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
