Opened 10 years ago

Last modified 5 years ago

#10085 new defect

The gen() method for power series over power series works incorrectly

Reported by: schilly Owned by: sage-combinat
Priority: major Milestone: sage-6.4
Component: combinatorics Keywords: LazyPowerSeries
Cc: axel.bacher@…, mhansen, mantepse Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description (last modified by chapoton)

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.

Change History (9)

comment:1 Changed 10 years ago by schilly

  • Description modified (diff)

comment:2 Changed 10 years ago by burcin

  • Cc mhansen added
  • Component changed from symbolics to combinatorics
  • Owner changed from burcin to sage-combinat

comment:3 Changed 7 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:4 Changed 7 years ago by mantepse

  • Cc mantepse added
  • Keywords LazyPowerSeries added

comment:5 Changed 7 years ago by mhansen

A fix is in #15673

comment:6 Changed 7 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:7 Changed 7 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:8 Changed 6 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:9 Changed 5 years ago by chapoton

  • Description modified (diff)
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