Opened 9 years ago

Closed 7 weeks ago

#32 closed defect (migrated)

knapsack cover cuts off optimal solution

Reported by: asm4 Owned by: rlh
Priority: major Milestone:
Component: Cgl Version:
Keywords: Cc:

Description

One of the users of SYMPHONY provided an instance on which the KnapsackCover cuts off the optimal solution.

The LP files and the code that reproduces the problem are located here:

http://coral.ie.lehigh.edu/~asm4/tmp/knapsack/

out1.lp is the original instance. out2.lp is the instance obtained after adding CglKnapsackCover inequalities. solving out2.lp with cplex or cbc gives a solution value of 401, while out1.lp gives 397.

Affects trunk and release version 0.54.2

Change History (3)

comment:1 Changed 9 years ago by rlh

  • Owner changed from somebody to rlh

Asked asm4 to try with lastest verion of stable.

comment:2 Changed 9 years ago by asm4

Stable version 0.55 also shows this defect for the same inputs and same setup as above.

comment:3 Changed 7 weeks ago by stefan

  • Resolution set to migrated
  • Status changed from new to closed

This ticket has been migrated to GitHub and will be resolved there: https://github.com/coin-or/Cgl/issues/32

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