#14082: PARI stack overflow crashes Sage
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Reporter: jdemeyer | Owner: jdemeyer
Type: defect | Status: new
Priority: critical | Milestone: sage-5.7
Component: c_lib | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: Jeroen Demeyer | Merged in:
Dependencies: | Stopgaps:
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Changes (by {'newvalue': u'Jeroen Demeyer', 'oldvalue': ''}):
* author: => Jeroen Demeyer
Old description:
> The following crashes Sage hard:
> {{{
> sage: i = CDF.0
> sage: fz=animate([line([zeta(s+i*t) for t in srange(0,50,0.01)]) for s in
> srange(0,0.9,0.01)],xmin=-1.5,ymin=-2,xmax=2.5,ymax=2)
> *** the PARI stack overflows !
> current stack size: 16000000 (15.259 Mbytes)
> [hint] you can increase GP stack with allocatemem()
>
> *** Error in the PARI system. End of program.
> }}}
>
> The problem is simple: instead of using the '''proper PARI interface'''
> in `sage/libs/pari/gen.pyx`, for some reason PARI is called directly in
> `sage/rings/complex_double.pyx`. This interface misses some features,
> such as cleaning up the PARI stack :-)
>
> This goes back to
> {{{
> changeset: 1292:28dfa54b6a23
> parent: 1273:97f9271f8637
> user: William Stein <[email protected]>
> date: Sun Sep 24 23:13:32 2006 -0700
> summary: Finished the 2nd draft of the double precision complex
> numbers.
> }}}
>
> Solution: use the proper PARI interface instead.
New description:
The following crashes Sage hard:
{{{
sage: i = CDF.0
sage: fz=animate([line([zeta(s+i*t) for t in srange(0,50,0.01)]) for s in
srange(0,0.9,0.01)],xmin=-1.5,ymin=-2,xmax=2.5,ymax=2)
*** the PARI stack overflows !
current stack size: 16000000 (15.259 Mbytes)
[hint] you can increase GP stack with allocatemem()
*** Error in the PARI system. End of program.
}}}
The problem is simple: instead of using the '''proper PARI interface''' in
`sage/libs/pari/gen.pyx`, for some reason PARI is called directly in
`sage/rings/complex_double.pyx`. This interface misses some features, such
as cleaning up the PARI stack :-)
I also noticed that all PARI computations in this module use a
'''precision of 1728 bits''' on 64-bit systems due to a misunderstanding
of PARI precision (machine words in the PARI library vs. decimal digits in
GP).
This code goes back to
{{{
changeset: 1292:28dfa54b6a23
parent: 1273:97f9271f8637
user: William Stein <[email protected]>
date: Sun Sep 24 23:13:32 2006 -0700
summary: Finished the 2nd draft of the double precision complex
numbers.
}}}
Solution: use the proper PARI interface instead.
--
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14082#comment:4>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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