#14677: Limit computation causes Sage to crash
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Reporter: tmonteil | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-6.3
Component: symbolics | Resolution:
Keywords: maxima | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Comment (by pbruin):
Unfortunately not fixed by #13973, despite comment:5. The crash appears
to be related to the `domain: complex` setting used by Sage. GDB shows
that it is still the same infinite recursion as in comment:4. This is
possibly caused by the fact that Maxima uses Gruntz's algorithm, which was
designed only for real functions.
With a patched Sage version of Maxima (5.33.0.p1, see #15033) using ECL:
{{{
(%i1) f: (x^x-sin(x)^sin(x))/(x^3*log(x));
x sin(x)
x - sin(x)
(%o1) -----------------
3
x log(x)
(%i2) limit(f, x, 0);
(%o2) und
(%i3) domain: complex;
(%o3) complex
(%i4) limit(f, x, 0);
Maxima encountered a Lisp error:
BINDING-STACK overflow at size 10240. Stack can probably be resized.
Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.
Maxima encountered a Lisp error:
Detected access to an invalid or protected memory address.
Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.
;;;
;;; Detected access to protected memory, also kwown as 'bus or
segmentation fault'.
;;; Jumping to the outermost toplevel prompt
;;;
}}}
(repeated many times, then a core dump).
Just for comparison, in a recent development version of Maxima (after
5.33.0) using GCL:
{{{
(%i4) limit(f, x, 0);
}}}
(no error message, the answer is an empty line). Finally, using SBCL:
{{{
(%i4) limit(f, x, 0);
INFO: Binding stack guard page unprotected
Binding stack guard page temporarily disabled: proceed with caution
INFO: Binding stack guard page reprotected
}}}
(just once, then returns to prompt).
--
Ticket URL: <http://trac.sagemath.org/ticket/14677#comment:9>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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