#10085: The gen() method for power series over power series works incorrectly
-----------------------------------+-----------------------------
Reporter: schilly | Owner: sage-combinat
Type: defect | Status: new
Priority: major | Milestone: sage-6.4
Component: combinatorics | Resolution:
Keywords: LazyPowerSeries | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Description changed by chapoton:
Old description:
> If I type the following:
> {{{
> S1 = LazyPowerSeriesRing(ZZ)
> S2 = LazyPowerSeriesRing(S1)
> y = S2.gen()
> y.coefficient(1) == 1
> }}}
> I get True, and
> {{{
> y.coefficient(1).coefficient(0)
> }}}
> gets me the "'int' object has no attribute 'coefficient'" error message.
>
> I solved the problem by changing the following line in the gen() method:
> {{{
> res = self._new_initial(1, Stream([0,1,0]))
> }}}
> by
> {{{
> res = self.term(1, 1)
> }}}
>
> The coefficient of order 1 in the series y should not be the integer 1,
> but the power series [1, 0, ...] in S1.
New description:
If I type the following:
{{{
S1 = LazyPowerSeriesRing(ZZ)
S2 = LazyPowerSeriesRing(S1)
y = S2.gen()
y.coefficient(1) == 1
}}}
I get True, and
{{{
y.coefficient(1).coefficient(0)
}}}
gets me the "'int' object has no attribute 'coefficient'" error message.
I solved the problem by changing the following line in the gen() method:
{{{
res = self._new_initial(1, Stream([0,1,0]))
}}}
by
{{{
res = self.term(1, 1)
}}}
The coefficient of order 1 in the series y should not be the integer 1,
but the power series [1, 0, ...] in S1.
--
--
Ticket URL: <http://trac.sagemath.org/ticket/10085#comment:9>
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