#8415: bug in quadratic field embedding into QQbar
-----------------------------+----------------------------------------------
Reporter: robertwb | Owner: was
Type: defect | Status: new
Priority: major | Milestone: sage-4.3.4
Component: number theory | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
-----------------------------+----------------------------------------------
Comment(by cremona):
{{{
sage: r = QQbar(-7).sqrt()
sage: s = r.conjugate()
sage: (r-s).exactify() # hangs
}}}
It's in the QQbqr code... The actual hanging is happening in a call to
pari's nffactor on line 1632 of qqbar.py. So I think it's yet another
manifestation of pari's nnffactor bugs:
{{{
j...@selmer%sage -gp
...
GP/PARI CALCULATOR Version 2.3.3 (released)
amd64 running linux (x86-64/GMP-4.2.1 kernel) 64-bit version
compiled: Feb 22 2010, gcc-4.3.3 (Ubuntu 4.3.3-5ubuntu4)
(readline v6.0 enabled, extended help available)
...
? nf = nfinit(y^2-y+2);
? nffactor(nf,x^2-x+2)
*** nffactor: the PARI stack overflows !
current stack size: 8000000 (7.629 Mbytes)
[hint] you can increase GP stack with allocatemem()
}}}
( from inside sage, this just hangs).
According to http://old.nabble.com/New-PARI-stable-
release-2.3.5-td27467266.html there are 3 bug-fixes to nffactor in 2.3.5
which is a bug-fix release. Current development version is 2.4.3, in
which the above example works fine. I have not tried 2.3.5.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8415#comment:4>
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.
