#10058: Segfault in backward and inverse FFT for 2**n elements
-------------------------------------+-------------------------------------
Reporter: mpatel | Owner: jason, jkantor
Type: defect | Status: needs_review
Priority: major | Milestone: sage-6.2
Component: numerical | Resolution:
Keywords: gsl, fft, | Merged in:
segfault | Reviewers: Luis Felipe Tabera
Authors: Mike Hansen, Luis | Alonso, Marc Mezzarobba
Felipe Tabera Alonso, Marc | Work issues:
Mezzarobba | Commit:
Report Upstream: N/A | 9beddc73f3003afe617d0a4dc76b741b25dd7e50
Branch: | Stopgaps:
u/mmezzarobba/10058-gsl_fft |
Dependencies: |
-------------------------------------+-------------------------------------
Changes (by {'newvalue': u'Mike Hansen, Luis Felipe Tabera Alonso, Marc
Mezzarobba', 'oldvalue': u'Mike Hansen, Luis Felipe Tabera Alonso'}):
* commit: => 9beddc73f3003afe617d0a4dc76b741b25dd7e50
* author: Mike Hansen, Luis Felipe Tabera Alonso => Mike Hansen, Luis
Felipe Tabera Alonso, Marc Mezzarobba
* branch: => u/mmezzarobba/10058-gsl_fft
* reviewer: Luis Felipe Tabera Alonso => Luis Felipe Tabera Alonso, Marc
Mezzarobba
Old description:
> Sage crashes when asked to do a backward or inverse FFT for sizes that
> are powers of two:
> {{{
> sage: a = FFT(5)
> sage: a[1] = 2
> sage: a.forward_transform()
> sage: a.backward_transform()
> sage: a = FFT(4)
> sage: a[1] = 2
> sage: a.forward_transform()
> sage: a.backward_transform()
>
> ------------------------------------------------------------
> 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).
> ------------------------------------------------------------
> }}}
> This is with 4.6.alpha2.
>
> Joal Heagney reported this problem on [http://groups.google.com/group
> /sage-devel/browse_thread/thread/7830e0c484a0f38d sage-devel].
>
> Apply: trac_10058.2.patch, trac_10058_doc.patch
New description:
Sage crashes when asked to do a backward or inverse FFT for sizes that are
powers of two:
{{{
sage: a = FFT(5)
sage: a[1] = 2
sage: a.forward_transform()
sage: a.backward_transform()
sage: a = FFT(4)
sage: a[1] = 2
sage: a.forward_transform()
sage: a.backward_transform()
------------------------------------------------------------
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).
------------------------------------------------------------
}}}
This is with 4.6.alpha2.
Joal Heagney reported this problem on [http://groups.google.com/group
/sage-devel/browse_thread/thread/7830e0c484a0f38d sage-devel].
--
Comment:
Gitified and rebased on top of 6.1. The second patch looks good to me,
except for minor points that I fixed in my two commits. Could seomeone
please check:
* that I rebased the code correctly;
* whether you agree with my changes?
(If both are ok, please go ahead and set the ticket's status to
`positive_review`.)
--
Ticket URL: <http://trac.sagemath.org/ticket/10058#comment:7>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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