limits to Limit [Re: Severe bug in Mathematica 6 - Limit - 1 - No more memory available. Mathematica kernel has shut down.]
- From: Daniel Lichtblau <danl@xxxxxxxxxxx>
- Date: Fri, 15 Jun 2007 12:08:20 -0700
On Jun 15, 1:20 pm, Vladimir Bondarenko <v...@xxxxxxxxxxxxxxx> wrote:
Limit[Sqrt[1/z^1000000000+z], z-> Infinity]
No more memory available.
Mathematica kernel has shut down.
Best wishes,
Vladimir Bondarenko
[...]
Looks like a reasonable consequence of sensible methodology. More
details below.
As a bug report, this would, hereabouts, be regarded poorly insofar as
it is overly complicated. The same behavior happens with:
In[26]:= Limit[1/z^1000000000+z, z->Infinity]
No more memory available.
Mathematica kernel has shut down.
Try quitting other applications and then retry.
An ambitious QA analyst might guess the problem is in a power series
expansion, and check as thus.
In[1]:= Unprotect[Series];
In[2]:= Series[a__]:= Null /; (Print[InputForm[ser[a]]];False)
In[3]:= Limit[1/z^1000000000+z, z->Infinity]
ser[(1 + z^1000000001)/z, {z, 0, 1}, Assumptions -> z^(-1) >
1073741824]
No more memory available.
This takes us to the cause of the crash. Limit recognized it had a
rational function in the variable z and, quite sensibly, attempted to
find a series expansion. That in turn uses a dense data structure and
ran out of memory. We now have the underlying example
Series[(1 + z^1000000001)/z, {z,0,2}]
Further removal of dross shows that
Series[(1 + z^1000000001), {z,0,2}]
will likewise crash. At this point someone (me) looks hard in a
debugger and sees the crash is from attempting to add SeriesData
objects with powers quite far apart.
1 + SeriesData[z, 0, {}, 1000000001, 1000000001, 1]
This is something I might look at further, though frankly I give it no
more than a low priority. Your classification of this as a "severe
bug" indicates some prioritization issues, to say the least.
Daniel Lichtblau
Wolfram Research
.
- Prev by Date: Re: solutions, missing and excess, to transcendental equations [Re: JB discovers yet another K-12 level Maple bug the long liver, 1992--2007--? (solve)]
- Next by Date: Re: big exponents in rational functions [Re: Yet another Maple regression bug, 2000--2007--? (trivial integral)]
- Previous by thread: solutions, missing and excess, to transcendental equations [Re: JB discovers yet another K-12 level Maple bug the long liver, 1992--2007--? (solve)]
- Next by thread: incurable definite integration behavior [Re: Bug in Mathematica 6 - Integrate - 1]
- Index(es):
Relevant Pages
|
