[Cbc] What does "bad ub change for column 35 from 3 to 7" mean?
John Forrest
john.forrest at fastercoin.com
Fri Mar 25 15:45:00 EDT 2011
Fixes in trunk seem to work.
Took 4 seconds when I tried with new version - but it may be chance.
John Forrest
On Fri, 2011-03-25 at 14:20 +0100, Kim Hansen wrote:
> Hi,
>
> (I have send this yesterday, but the first message appears to have been lost).
>
> I have a MIP problem that cbc has a problem with:
> http://ange.dk/~kim/bad_ub.mps.gz
>
> It prints a lot of errors like this:
> Cbc0010I After 4000 nodes, 229 on tree, 35778 best solution, best
> possible 32038.1 (330.41 seconds)
> bad ub change for column 35 from 3 to 7
> bad ub change for column 40 from 2 to 3
> bad lb change for column 49 from 1 to -0
> bad ub change for column 35 from 6 to 7
>
> What does it mean and what can I do to avoid it?
>
> I have the problem with the cbc 2.5.0, it is the version that is in
> Debian Squeeze. When I use the older cbc 2.20.00 from CoinAll 1.2.0 it
> does not have the problem. Actually it solves the problem with the old
> solver in about 5 seconds while the new version uses 850 seconds.
>
> Regards,
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