Can someone test this in alpha versions of 4.6?

[Jason Grout]

One of my interacts for class is segfaulting in 4.6, but worked fine in
4.5.2. The problem is illustrated below:

sage: V=(QQ^2).span_of_basis([[1,1]])
sage: v=V([1,1])
sage: x=sqrt(2)*v
sage: 3*x

------------------------------------------------------------
Unhandled SIGSEGV: A segmentation fault occurred in Sage.
This probably occurred because a *compiled* component
of Sage has a bug in it (typically accessing invalid memory)
or is not properly wrapped with _sig_on, _sig_off.
You might want to run Sage under gdb with 'sage -gdb' to debug this.
Sage will now terminate (sorry).
------------------------------------------------------------

I'm trying to track this down at
http://trac.sagemath.org/sage_trac/ticket/10250, and it seems to involve
pynac and the coercion system. Does anyone have alpha versions of 4.6
(or 4.5.3, for that matter) that they can test the above code in so we
can try to pinpoint what change caused the problem? The code above
doesn't work for my copy of 4.6alpha3, for example.

Thanks,

Jason

[John H Palmieri]

On Nov 11, 8:20 am, Jason Grout <jason-s...@creativetrax.com> wrote:
> One of my interacts for class is segfaulting in 4.6, but worked fine in
> 4.5.2.  The problem is illustrated below:
>
> sage: V=(QQ^2).span_of_basis([[1,1]])
> sage: v=V([1,1])
> sage: x=sqrt(2)*v
> sage: 3*x
>
> ------------------------------------------------------------
> Unhandled SIGSEGV: A segmentation fault occurred in Sage.
> This probably occurred because a *compiled* component
> of Sage has a bug in it (typically accessing invalid memory)
> or is not properly wrapped with _sig_on, _sig_off.
> You might want to run Sage under gdb with 'sage -gdb' to debug this.
> Sage will now terminate (sorry).
> ------------------------------------------------------------
>

> I'm trying to track this down athttp://trac.sagemath.org/sage_trac/ticket/10250, and it seems to involve

> pynac and the coercion system.  Does anyone have alpha versions of 4.6
> (or 4.5.3, for that matter) that they can test the above code in so we
> can try to pinpoint what change caused the problem?  The code above
> doesn't work for my copy of 4.6alpha3, for example.

I have 4.5.3 on both a Mac (OS X 10.6) and on sage.math, and on both,
your example works fine. I have 4.6.alpha1 on the same Mac, and I get
the segfault. (I also have 4.6.alpha2 on an OpenSolaris machine, and
that also segfaults.)

--
John

[Jason Grout]

Thanks! That helped tremendously. Now it seems like the problem may
have been introduced in http://trac.sagemath.org/sage_trac/ticket/9502

I'll keep testing...

Thanks,

Jason