Opened 4 years ago
Closed 3 years ago
#25780 closed defect (fixed)
Normalize bound checking in points function
Reported by:  raghukul01  Owned by:  

Priority:  major  Milestone:  sage8.3 
Component:  algebraic geometry  Keywords:  algebraic scheme, gsoc2018 
Cc:  bhutz, raghukul01  Merged in:  
Authors:  Raghukul Raman  Reviewers:  Ben Hutz 
Report Upstream:  N/A  Work issues:  
Branch:  b9266c6 (Commits, GitHub, GitLab)  Commit:  b9266c657e20c8832e043bddd24d1abace89dc5a 
Dependencies:  Stopgaps: 
Description
Consider this example
sage: P.<x,y> = ProjectiveSpace(QQ, 1) sage: print sorted(list(P.points_of_bounded_height(bound=3))) [(2 : 1), (1 : 1), (1/2 : 1), (0 : 1), (1/2 : 1), (1 : 0), (1 : 1), (2 : 1)]
Points of height 3 are not present.
sage: P.<x,y,z> = ProjectiveSpace(2,QQ) sage: list(P.points_of_bounded_height(bound=5))
here we have some points like (2 : 4/3 : 1)
which have height=6, if we use enum_projective_rational_field function results are as we would expect. So the underlying definition for height of rational points need to be uniform in all these functions.
Change History (6)
comment:1 Changed 4 years ago by
 Branch set to u/raghukul01/normalize_bound_checking_in_points_function
comment:2 Changed 4 years ago by
 Commit set to 26c28949343ffa6dc2d1ba1e142fe4a28d312543
 Status changed from new to needs_review
comment:3 Changed 4 years ago by
Just one comment here. What do you think about using?
self.point(c, check=False)
It is about twice as fast and since the function is for projective space (not a subscheme) it's not like we need to check that the point is welldefined. It will cause them not to be normalized to the last coordinate to 1 though.
I have the doctests running now, but I don't really expect a failure.
comment:4 Changed 4 years ago by
 Commit changed from 26c28949343ffa6dc2d1ba1e142fe4a28d312543 to b9266c657e20c8832e043bddd24d1abace89dc5a
Branch pushed to git repo; I updated commit sha1. New commits:
b9266c6  25780: Improved conversion to projective point

comment:5 Changed 4 years ago by
 Reviewers set to Ben Hutz
 Status changed from needs_review to positive_review
comment:6 Changed 3 years ago by
 Branch changed from u/raghukul01/normalize_bound_checking_in_points_function to b9266c657e20c8832e043bddd24d1abace89dc5a
 Resolution set to fixed
 Status changed from positive_review to closed
New commits:
25780: Corrected algorithm in points function