[Cbc] What does "bad ub change for column 35 from 3 to 7" mean?

[Kim Hansen]

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,
-- 
Kim Hansen
Vadgårdsvej 3, 2.tv
2860 Søborg
Phone: +45 3091 2437