Opened 2 years ago

Closed 2 years ago

#28174 closed defect (fixed)

Fixed typo for dehomogenization of non-endomorphisms

Reported by: gh-HTalbott Owned by:
Priority: major Milestone: sage-8.9
Component: geometry Keywords: SI2019
Cc: gh-Torrencem Merged in:
Authors: Matt Torrence, Henry Talbott Reviewers: Ben Hutz
Report Upstream: N/A Work issues:
Branch: 4f462a0 (Commits, GitHub, GitLab) Commit: 4f462a0255fef1590a6979d4b95fee204f55b432
Dependencies: Stopgaps:

Status badges

Description (last modified by gh-HTalbott)

The following code is broken:

sage: P1.<x,y> = ProjectiveSpace(QQ,1)
sage: P2.<u,v,w> = ProjectiveSpace(QQ,2)
sage: H = Hom(P2,P1)
sage: f = H([u*w, v^2 + w^2])
sage: f.dehomogenize((2,1))
# raises IndexError

This seems to be because of a typo in, in the dehomogenization method. The method uses the domain to find the number of generators of the input, when it should be using the codomain.

Change History (5)

comment:1 Changed 2 years ago by gh-HTalbott

  • Type changed from PLEASE CHANGE to defect

comment:2 Changed 2 years ago by gh-Torrencem

  • Authors set to Matt Torrence, Henry Talbott
  • Branch set to u/gh-Torrencem/28174_dehomogenization_fix
  • Commit set to 4f462a0255fef1590a6979d4b95fee204f55b432
  • Status changed from new to needs_review

New commits:

4f462a028174: Fix dehomogenization error for non-endomorphisms

comment:3 Changed 2 years ago by gh-HTalbott

  • Description modified (diff)

comment:4 Changed 2 years ago by bhutz

  • Reviewers set to Ben Hutz
  • Status changed from needs_review to positive_review

Looks good to me.

comment:5 Changed 2 years ago by vbraun

  • Branch changed from u/gh-Torrencem/28174_dehomogenization_fix to 4f462a0255fef1590a6979d4b95fee204f55b432
  • Resolution set to fixed
  • Status changed from positive_review to closed
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