On Nov 28, 2007 10:43 AM, Jennifer S. Balakrishnan <[EMAIL PROTECTED]> wrote:
> I'm trying to integrate a list of Laurent series, and it seems that
> once the list has more than 4 elements, Sage gets upset:
The problem is:
sage: A.<t> = LaurentSeriesRing(QQ)
sage: (-2*t^(-4) + O(t^8)).integral()
Traceback (most recent call last):
...
IndexError: list index out of range
This is because of this code in rings/laurent_series_ring_element.pyx not
being coded correctly around line 880:
if n < 0:
v = [a[i]/(n+i+1) for i in range(-1-n)] + [0]
else:
v = []
v += [a[i]/(n+i+1) for i in range(max(-n,0), len(a))]
try:
So you or somebody should fix that and submit a patch :-).
It's now:
http://trac.sagemath.org/sage_trac/ticket/1302
William
>
> sage: A.<t> = LaurentSeriesRing(QQ)
> sage: B = [-2*t^4 + O(t^16), -2*t^2 + O(t^14), -2 + O(t^12), -2*t^-2 +
> O(t^10), -2*t^-4 + O(t^8), -2*t^-6 + O(t^6)]
> sage: for i in range(6):
> ....: B[i] = integral(B[i])
> ....:
> ---------------------------------------------------------------------------
> <type 'exceptions.IndexError'> Traceback (most recent call last)
>
> /home/jen/<ipython console> in <module>()
>
> /home/jen/sage-2.8.13-use_this_on_sage_dot_math-x86_64-Linux/local/lib/python2.5/site-packages/sage/misc/functional.py
> in integral(x, *args, **kwds)
> 449 """
> 450 if hasattr(x, 'integral'):
> --> 451 return x.integral(*args, **kwds)
> 452 else:
> 453 from sage.calculus.calculus import SR
>
> /home/jen/laurent_series_ring_element.pyx in
> sage.rings.laurent_series_ring_element.LaurentSeries.integral()
>
> <type 'exceptions.IndexError'>: list index out of range
> sage: B
>
> [-2/5*t^5 + O(t^17),
> -2/3*t^3 + O(t^15),
> -2*t + O(t^13),
> 2*t^-1 + O(t^11),
> -2*t^-4 + O(t^8), <================== stopped integrating here
> -2*t^-6 + O(t^6)]
>
> What's going on?
>
> Jen
>
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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