#11889: Power series exp fails uninformatively when base ring has nonzero
characteristic
-----------------------------+----------------------------------------------
Reporter: davidloeffler | Owner: AlexGhitza
Type: defect | Status: new
Priority: trivial | Milestone: sage-4.7.2
Component: algebra | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
-----------------------------+----------------------------------------------
{{{
sage: R.<x> = GF(2)[[]]
sage: f = x + x^2 + O(x^5)
sage: exp(f)
---------------------------------------------------------------------------
ZeroDivisionError Traceback (most recent call
last)
/home/masiao/<ipython console> in <module>()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/functions/log.pyc in __call__(self, x, coerce, hold, prec,
dont_call_method_on_arg)
128 return x.n(prec)
129 return GinacFunction.__call__(self, x, coerce=coerce,
hold=hold,
--> 130 dont_call_method_on_arg=dont_call_method_on_arg)
131
132 exp = Function_exp()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/symbolic/function.so in
sage.symbolic.function.GinacFunction.__call__
(sage/symbolic/function.cpp:6652)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/rings/power_series_ring_element.so in
sage.rings.power_series_ring_element.PowerSeries.exp
(sage/rings/power_series_ring_element.c:11024)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/rings/power_series_ring_element.so in
sage.rings.power_series_ring_element.PowerSeries.solve_linear_de
(sage/rings/power_series_ring_element.c:10857)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/rings/power_series_ring_element.so in
sage.rings.power_series_ring_element._solve_linear_de
(sage/rings/power_series_ring_element.c:12441)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/rings/power_series_ring_element.so in
sage.rings.power_series_ring_element._solve_linear_de
(sage/rings/power_series_ring_element.c:12656)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/rings/power_series_ring_element.so in
sage.rings.power_series_ring_element._solve_linear_de
(sage/rings/power_series_ring_element.c:12379)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/structure/element.so in
sage.structure.element.RingElement.__div__
(sage/structure/element.c:12803)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/structure/coerce.so in
sage.structure.coerce.CoercionModel_cache_maps.bin_op
(sage/structure/coerce.c:6436)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/structure/element.so in
sage.structure.element.RingElement.__div__
(sage/structure/element.c:12777)()
/usr/local/sage/sage-4.7.1/local/lib/python2.6/site-
packages/sage/rings/finite_rings/integer_mod.so in
sage.rings.finite_rings.integer_mod.IntegerMod_int._div_
(sage/rings/finite_rings/integer_mod.c:19299)()
ZeroDivisionError: Inverse does not exist.
}}}
There's no way of making this work in a mathematically meaningful way, but
it could certainly be made to fail a bit more gracefully!
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11889>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
