[Cbc] confused about depth

[James Howey]

I have a model that occasionally gets lost in the weeds.

 

Cbc0010I After 6200 nodes, 4814 on tree, 1e+50 best solution, best possible
0 (97.67 seconds)

Cbc0020I Exiting on maximum time

Cbc0005I Partial search - best objective 1e+50 (best possible 0), took
549614 iterations and 6236 nodes (100.02 seconds)

Cbc0035I Maximum depth 4816, 0 variables fixed on reduced cost

 

My confusion stems from the reported maximum depth of 4816. I have only 270
(sos) objects in the model.

 

It would seem that by the time I reach 270 I could judge this node integer
feasible or not, and continue in shallower depths. 

 

Is this behavior by design, and if, as I suspect, it is, are there
situations where this strategy is effective? Maybe even my situation?

 

Additional info: In my situation, there is an order to the objects that will
reliably give you an infeasible/integer solution judgment by the time you
reach 270. I have prioritized the objects in this order and turned off
strong branching. 

 

What would happen if I hacked the branch decision logic to just  never split
the last level? Is branch logic where I will be spending my time in the
future?

 

Thanks for any light you can shed.

 

jkh

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