Opened 3 years ago

Closed 3 years ago

#24154 closed defect (fixed)

Fix equation handling of Polyhedron.to_linear_program() and thus integral_points_count(preprocess=True)

Reported by: mkoeppe Owned by:
Priority: critical Milestone: sage-8.1
Component: geometry Keywords:
Cc: SimonKing, vdelecroix, jipilab Merged in:
Authors: Matthias Koeppe Reviewers: Dima Pasechnik
Report Upstream: N/A Work issues:
Branch: 6ad4bf7 (Commits, GitHub, GitLab) Commit: 6ad4bf7868923b9382bce80b4372e9ad014d0cd3
Dependencies: Stopgaps:

Status badges

Description (last modified by mkoeppe)

As reported in ​https://groups.google.com/d/msg/sage-devel/TuF0CidR-JI/8-zpcu-MCgAJ, the preprocessing code in integral_points_count sometimes fails. This is ultimately because Polyhedron.to_linear_program does not handle equations correctly. 

sage: P = Polyhedron(vertices=[[19]])
sage: P.to_linear_program().show()
Maximization:
  

Constraints:
  constraint_0: -19 <= x_0 <= -19
Variables:
  x_0 is a continuous variable (min=-oo, max=+oo)
sage: P.to_linear_program().polyhedron().vertices_list()
[[-19]]

Change History (6)

comment:1 Changed 3 years ago by mkoeppe

  • Description modified (diff)

comment:2 Changed 3 years ago by roed

  • Component changed from PLEASE CHANGE to geometry

comment:3 Changed 3 years ago by mkoeppe

  • Branch set to u/mkoeppe/fix_equation_handling_polyhedron_to_linear_program

comment:4 Changed 3 years ago by mkoeppe

  • Authors set to Matthias Koeppe
  • Commit set to 6ad4bf7868923b9382bce80b4372e9ad014d0cd3
  • Status changed from new to needs_review

New commits:

​6ad4bf724154: Fix equation handling of Polyhedron.to_linear_program()

comment:5 Changed 3 years ago by dimpase

  • Reviewers set to Dima Pasechnik
  • Status changed from needs_review to positive_review

OK, makes sense.

comment:6 Changed 3 years ago by vbraun

  • Branch changed from u/mkoeppe/fix_equation_handling_polyhedron_to_linear_program to 6ad4bf7868923b9382bce80b4372e9ad014d0cd3
  • Resolution set to fixed
  • Status changed from positive_review to closed
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