[Cgl] knapsackcover seems to cut off optimal solution

[Ashutosh Mahajan]

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