#18787: symbolic modular integers still broken
-------------------------------------+-------------------------------------
Reporter: tmonteil | Owner:
Type: defect | Status: needs_work
Priority: major | Milestone: sage-6.9
Component: symbolics | Resolution:
Keywords: | Merged in:
Authors: Ralf Stephan | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/rws/bug_with_products_of_symbolic_variables_with_modular_integers|
6f9e551e2110aa700b29eee6f379ec93890d7ba8
Dependencies: | Stopgaps:
-------------------------------------+-------------------------------------
Changes (by rws):
* status: needs_info => needs_work
* milestone: sage-pending => sage-6.9
* dependencies: #18980 =>
Old description:
> As reported on [http://ask.sagemath.org/question/27196/multiplying-
> matrices-with-different-parents/ this ask question]
>
> {{{
> sage: _ = var('A,B')
> sage: (A + 3*B)*Zmod(9)(6)
> 0*B
> }}}
>
> while the result should be `6*A`.
>
> It seems that the internal state of these objects is really messed up:
> {{{
> sage: _ = var('A,B')
> sage: (3*A + 3*B)*Zmod(9)(6) # Yes, the output is really empty!
>
> sage: (3*A + 3*B)*Zmod(9)(6)*A
> ------------------------------------------------------------------------
> Unhandled SIGSEGV: A segmentation fault occurred in Sage.
> This probably occurred because a *compiled* component of Sage has a bug
> in it and is not properly wrapped with sig_on(), sig_off().
> Sage will now terminate.
> ------------------------------------------------------------------------
> }}}
New description:
> {{{
> sage: f(x) = Zmod(7)(1) * x**2 + Zmod(9)(1) * x**3
> sage: f(1)
> 2
> sage: Zmod(7)(1) + Zmod(9)(1)
...
TypeError: unsupported operand parent(s) for '+': 'Ring of integers modulo
7' and 'Ring of integers modulo 9'
> }}}
--
Comment:
Replying to [comment:27 vdelecroix]:
> Why is it in sage-pending?
I didn't want patchbot on it.
--
Ticket URL: <http://trac.sagemath.org/ticket/18787#comment:28>
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