[Coin-discuss] Suggestions on how to go about tuning?

[hpwalton at comcast.net]

Is there doc anywhere on suggestions for tuning CBC/Clp? 

I'm having a performance issue with a specific instance of data.  Other instances of the same data run very quickly...(a few seconds), and this is running in terms of hours.

I'm thinking CBC just gets off on the wrong foot.  I'm able to solve it with another open source solver very rapidly (in the "few minutes" range).   

I was hoping I could learn enough on my own, but at this point I'm not really sure the most effective way to go about it.  I'm not looking for someone to do the thinkin' for me..more lookin' for some guidance on CBC specifically.

It is (roughly) a Hamiltonian Cycle problem...I've indicated some SOS type 1 constraints and that helped get an answer fast, but the answer isn't all that good.

It's a minimization problem, the optimal solution is 2.1, the first integer answer CBC finds is 3.6, and the "lower bound" is 1.  the cost/weights are non-negative small decimals (ranging from zero to 2.5).

The lower bound doesn't start coming up for quite a while...so it spends a lot of time exploring nodes which are not fruitful.

Any suggestions are welcome.  I've seen at least one other request in the archives for tuning paramters...

Thanks,
Philip
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