#20428: crash with ultraspherical polynomials
-------------------------+----------------------------
Reporter: rws | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-7.2
Component: symbolics | Keywords:
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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{{{
%time _=ultraspherical(10000,7/5,x)
...
RuntimeError: ECL says: Memory limit reached. Please jump to an outer
pointer, quit program and enlarge the
memory limits before executing the program again.
}}}
Currently Maxima is called with ultraspherical (Gegenbauer) polynomials
but already a naive Python implementation is faster:
{{{
sage: def u(n,a):
return sum((-1)^k*prod(i for i in srange(a,
n-k+a))/factorial(n-2*k)/factorial(k)*(2*x)^(n-2*k) for k in
range(floor(n/2)+1))
....:
sage: %time _=u(10000,7/5)
CPU times: user 1min 43s, sys: 128 ms, total: 1min 43s
Wall time: 1min 43s
}}}
and the Maxima version would be not even expanded. A direct Pynac
implementation should need only seconds.
--
Ticket URL: <http://trac.sagemath.org/ticket/20428>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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