[Cgl] knapsackcover seems to cut off optimal solution

[Ashutosh Mahajan]

bug still persists. ticket opened. thanks.

ashutosh

On Thu, 10 Dec 2009, Robin Lougee-Heimer wrote:

>    Ashutosh:
> 
>    If this is still an issue, will you please report it in the Cgl bug
>    tracking factility?
> 
>    https://projects.coin-or.org/Cgl/report
> 
>    thanks,
>    Robin
>    ----------------------------------------------------------------------------------
>    Robin Lougee-Heimer, PhD
>    Program Manager, COIN-OR
>    IBM TJ Watson Research Center
>    1101 Kitchawan Road, Yorktown Heights, NY 10598
>    ph: 914-945-3032   fax: 914-945-3434
>    robinlh at us.ibm.com
>    http://www.coin-or.org
> 
>    Ashutosh Mahajan                   To cgl at list.coin-or.org
>    <asm4 at lehigh.edu>                  cc
>    Sent by:                      Subject [Cgl] knapsackcover seems to cut off
>    cgl-bounces at list.coin-or.org          optimal solution
> 
>    10/26/2009 03:18 PM
> 
>    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.
> 
>    This behaviour was seen with latest stable r792. i expect it in the
>    release
>    version as well (though i did not check). is this a bug, or something
>    wrong
>    with my construction?
> 
>    thanks.
>    --
>    regards
>    Ashutosh Mahajan
>    http://coral.ie.lehigh.edu/~asm4
> 
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--
regards
Ashutosh Mahajan
http://coral.ie.lehigh.edu/~asm4