Opened 5 years ago
Closed 5 years ago
#17441 closed defect (fixed)
Change ring fails for SchemeMorphism_polynomial defined with fraction field elements
Reported by:  gjorgenson  Owned by:  

Priority:  minor  Milestone:  sage6.5 
Component:  algebraic geometry  Keywords:  
Cc:  bhutz  Merged in:  
Authors:  Grayson Jorgenson  Reviewers:  Ben Hutz 
Report Upstream:  N/A  Work issues:  
Branch:  0db9c36 (Commits)  Commit:  0db9c36faa39f251c4443dfe0c228214a588019e 
Dependencies:  Stopgaps: 
Description (last modified by )
If a SchemeMorphism_polynomial is defined with fraction field elements, change ring fails; in that case, change_ring should be called on the numerator and denominator:
A.<x,y> = AffineSpace(QQ,2) H = Hom(A,A) f = H([3*x^2/y,y^2/x]) f.change_ring(RR)
Change History (8)
comment:1 Changed 5 years ago by
 Branch set to u/gjorgenson/ticket/17441
 Created changed from 12/03/14 17:56:02 to 12/03/14 17:56:02
 Modified changed from 12/03/14 17:56:02 to 12/03/14 17:56:02
comment:2 Changed 5 years ago by
 Commit set to 51a7d2f9c74e9b79a9f2822efcdf6d8deac028a3
 Status changed from new to needs_review
comment:3 Changed 5 years ago by
 Description modified (diff)
comment:4 Changed 5 years ago by
 Reviewers set to Ben Hutz
 Status changed from needs_review to needs_work
This looks good except for one minor thing. In the code you have
if isinstance(f,FractionFieldElement) == True
Make this
if isinstance(f, FractionFieldElement):
comment:5 Changed 5 years ago by
 Commit changed from 51a7d2f9c74e9b79a9f2822efcdf6d8deac028a3 to 0db9c36faa39f251c4443dfe0c228214a588019e
Branch pushed to git repo; I updated commit sha1. New commits:
0db9c36  17441: Removed redundant check

comment:6 Changed 5 years ago by
 Status changed from needs_work to needs_review
comment:7 Changed 5 years ago by
 Status changed from needs_review to positive_review
comment:8 Changed 5 years ago by
 Branch changed from u/gjorgenson/ticket/17441 to 0db9c36faa39f251c4443dfe0c228214a588019e
 Resolution set to fixed
 Status changed from positive_review to closed
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New commits:
Calls change_ring separately on the numerator and denominator of fraction field elements in the morphism