Opened 6 years ago

Closed 3 years ago

#13696 closed defect (fixed)

process chained equalities with different signs correctly

Reported by: dimpase Owned by: ncohen
Priority: major Milestone: sage-duplicate/invalid/wontfix
Component: linear programming Keywords:
Cc: vbraun, ppurka, ncohen Merged in:
Authors: Reviewers: Jeroen Demeyer
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: #14540 Stopgaps:

Description (last modified by mkoeppe)

we have to deal with what remained from #12091. At least, report errors for the inputs like the following: 

sage: p = MixedIntegerLinearProgram()
sage: b = p.new_variable()
sage: b[0] <= 555*b[1] >= 2
sage: b[0] <= 555*b[1] == 2

which even with #12091 are incorrectly processed 

sage: b[0] <= 555*b[1] >= 2
2 <= x_0 <= 555*x_1
sage: b[0] <= 555*b[1] == 2
555*x_1 == 2

Change History (14)

comment:1 Changed 6 years ago by dimpase

  • Type changed from PLEASE CHANGE to defect

comment:2 Changed 6 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:3 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:4 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:5 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:6 Changed 3 years ago by mkoeppe

  • Description modified (diff)

Description modified to make the example self-contained.

comment:7 Changed 3 years ago by dimpase

  • Milestone changed from sage-6.4 to sage-wishlist

comment:8 Changed 3 years ago by jdemeyer

  • Dependencies changed from #12091 to #14540

comment:9 Changed 3 years ago by jdemeyer

  • Milestone changed from sage-wishlist to sage-7.2

comment:10 Changed 3 years ago by mkoeppe

And how about: 

sage: b[0] <= 3 <= 4 <= b[1]
4 <= x_1

comment:11 Changed 3 years ago by jdemeyer

  • Milestone changed from sage-7.2 to sage-duplicate/invalid/wontfix
  • Reviewers set to Jeroen Demeyer
  • Status changed from new to needs_review

comment:12 Changed 3 years ago by jdemeyer

  • Status changed from needs_review to positive_review

comment:13 Changed 3 years ago by jdemeyer

The reviewer of #14540 was not happy with a partial solution, so it's probably better to thoroughly fix the problem on #14540.

comment:14 Changed 3 years ago by vbraun

  • Resolution set to fixed
  • Status changed from positive_review to closed
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