#10100: Segfault calling change_ring(RR) on a symbolic polynomial
--------------------------------------------+-------------------------------
Reporter: davidloeffler | Owner: burcin
Type: defect | Status: needs_review
Priority: major | Milestone: sage-4.7.1
Component: symbolics | Keywords:
Work_issues: | Upstream: N/A
Reviewer: Volker Braun, Jeroen Demeyer | Author: Mike Hansen
Merged: | Dependencies:
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Changes (by jdemeyer):
* reviewer: Volker Braun => Volker Braun, Jeroen Demeyer
Old description:
> The following code seems to crash Sage on some (but not all) systems:
> {{{
> sage: a = var('a')
> sage: R.<x> = a.parent()[]
> sage: (x - a).change_ring(RR) # boom!
> }}}
>
> This bug was originally spotted when calculating char polys of symbolic
> matrices:
> {{{
> sage: a,b,c= var('a,b,c')
> sage: mprime = matrix([[01,b+1,2],[a+1,2,1],[2,1,c+1]])
> sage: cp = mprime.charpoly()
> sage: cp.real_roots() # boom!
> }}}
> See [http://groups.google.co.uk/group/sage-
> devel/browse_thread/thread/0ea6c973a56191ab/e91868cd98f7fb74 this sage-
> devel thread].
>
> Apply
> * [attachment:trac_10100.patch]
> * [attachment:trac_10100_wrap_sigonoff.patch]
New description:
The following code seems to crash Sage on some (but not all) systems:
{{{
sage: a = var('a')
sage: R.<x> = a.parent()[]
sage: (x - a).change_ring(RR) # boom!
}}}
This bug was originally spotted when calculating char polys of symbolic
matrices:
{{{
sage: a,b,c= var('a,b,c')
sage: mprime = matrix([[01,b+1,2],[a+1,2,1],[2,1,c+1]])
sage: cp = mprime.charpoly()
sage: cp.real_roots() # boom!
}}}
See [http://groups.google.co.uk/group/sage-
devel/browse_thread/thread/0ea6c973a56191ab/e91868cd98f7fb74 this sage-
devel thread].
Apply
* [attachment:trac_10100.patch]
* [attachment:trac_10100_wrap_sigonoff.patch]
* [attachment:10100_sig_review.patch]
--
Comment:
Positive review, modulo my reviewer patch.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10100#comment:10>
Sage <http://www.sagemath.org>
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