[Dip] What is "Solution Update" in the statistics?

[Matthew Galati]

Hi Kim,

The "Total Solution Update" refers to the amount of time spent in solving
the master problem. So, for PC, that is the amount of time in solving the DW
master LP. It is pretty common for alot of relative time to be spent in
there. Of course, that also depends on the instance (and the solver - CPX vs
CLP, for example).

The price+branch heuristic is very effective. Without it, I am not too
surprised you don't find integer solutions. Without it, you would need a
user-defined heuristic, general MIP heuristics (not hooked up currently),
good branching (DIP's is naive) or luck. So - I do find that it is important
to use.

With respect to performance, if you have a particular instance in mind that
you want me to look at, let me know.

Thanks,
Matt


On Fri, Dec 17, 2010 at 5:55 AM, kim <kim at hamilton-vejlin.dk> wrote:

> In the Decomp Statistics time expenditure breakdown, what does "Total
> Solution Update" cover?
>
> For my runs I frequently spend 60% of the time in "solution update".
> Note that I have disabled the upper bounding heuristic and do not
> typically locate even a single feasible solution.
>
> -Kim
>
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