[Coin-discuss] BCP: An integer feasible node may not be pruned leading to abort.

[Miroslav Karamanov]

When a feasible solution is found, bounds are updated but 
actual pruning of the node is done by bound (line 100, 
BCP_lp_main_loop.cpp). But pruning is not guaranteed. 
Whether it will occur depends on the granularity and the 
difference between the objective value stored at p.node and 
the objective value of the same solution computed during the 
feasibility tests.
The former is used for pruning the node in the main loop.
The latter is used for updating the upper bound. (It is 
computed in BCP_lp_user::test_full (my favorite function 
these days) by rounding the variables first.)
Clearly, there could be a difference.

Suggested fixes:
1. do not consider bounds, just prune all integer feasible 
nodes.
2. be consistent with the objective value of the particular 
solution.
3. both.

Best,
Miroslav