Opened 9 years ago
Closed 5 years ago
#10846 closed defect (fixed)
Conversion of PowerSeries > SR bug
Reported by:  vbraun  Owned by:  burcin 

Priority:  major  Milestone:  sage6.4 
Component:  symbolics  Keywords:  
Cc:  Merged in:  
Authors:  Ralf Stephan  Reviewers:  Volker Braun 
Report Upstream:  N/A  Work issues:  
Branch:  26df71b (Commits)  Commit:  26df71b66563b3785d8180412f5979a62f1ba0c1 
Dependencies:  Stopgaps: 
Description
If I convert a powerseries into the symbolic ring, it does not have any variables.
sage: R.<x> = PowerSeriesRing(QQ) sage: s = R([1,2,3,4,5],prec=10) sage: s 1 + 2*x + 3*x^2 + 4*x^3 + 5*x^4 + O(x^10) sage: SR(s) 1 + 2*x + 3*x^2 + 4*x^3 + 5*x^4 + O(x^10) sage: SR(s).variables() ()
Running simplify() fixes it:
sage: SR(s).simplify().variables() (x,)
Change History (14)
comment:1 Changed 9 years ago by
comment:2 Changed 6 years ago by
 Milestone changed from sage5.11 to sage5.12
comment:3 Changed 6 years ago by
 Milestone changed from sage6.1 to sage6.2
comment:4 Changed 6 years ago by
 Milestone changed from sage6.2 to sage6.3
comment:5 Changed 5 years ago by
 Milestone changed from sage6.3 to sage6.4
comment:6 Changed 5 years ago by
 Branch set to u/rws/conversion_of_powerseries____sr_bug
comment:7 Changed 5 years ago by
 Commit set to 99916f9b08354e99489d59858311bf57f342c24b
 Status changed from new to needs_review
New commits:
99916f9  10846: fix conversion of power series to symbolic series

comment:8 Changed 5 years ago by
I'm considering moving all series methods into a subclass SymbolicSeries
of Expression
because they need to be handled apart from expressions, anyway. In a separate file the documentation would be easier to find as well. Comments?
comment:9 Changed 5 years ago by
Note that GiNaC will not add an order term to series from polynomials even if requested. I would consider this a bug. The reason is that pseries are formal, anyway, so they should be fully manipulatable.
This restriction can be circumvented with a simple trick.
comment:10 Changed 5 years ago by
 Commit changed from 99916f9b08354e99489d59858311bf57f342c24b to 26df71b66563b3785d8180412f5979a62f1ba0c1
Branch pushed to git repo; I updated commit sha1. New commits:
26df71b  10846: handle order term correctly

comment:11 Changed 5 years ago by
Passes all tests in a 6.5 patchbot run.
comment:12 Changed 5 years ago by
 Reviewers set to Volker Braun
 Status changed from needs_review to positive_review
comment:13 Changed 5 years ago by
Followup in #18094 which uncovers a bug with bigoh handling.
comment:14 Changed 5 years ago by
 Branch changed from u/rws/conversion_of_powerseries____sr_bug to 26df71b66563b3785d8180412f5979a62f1ba0c1
 Resolution set to fixed
 Status changed from positive_review to closed
A possibly related bug is Trac #9769: Coercon problems to symbolic ring