[Symphony] Help/Feature request

[Ted Ralphs]

On Thu, Oct 13, 2011 at 11:13 AM, Haroldo Santos
<haroldo.santos at gmail.com>wrote:

> Hi,
>
> I've been using SYMPHONY in the last days and I'm really appreciating how
> it executes well in parallel, great job !
>
> There are some questions I have about heuristics :
>
> Is there any command line parameter to activate (increase number of
> passes) of the feasibility pump heuristic ?
>

There isn't a way to set the parameters related to the feasibility pump on
the command line, but these parameters can easily be set in a parameter
file with the "-f" command-line switch. The parameters associated with the
feasibility pump are the ones that begine with "fp_". You can find them in
master_func.c by searching for the string "fp_" (line 2957 in the trunk
version). Does this help?


> Is there any way to inform a file with one (or more) initial feasible
> solutions (this would be really nice) ?
>

For what purpose? There is a way to give an initial solution to SYMPHONY,
but it's really just used to get an initial bound. If no better solution is
found by the end, it will then be reported as the optimum. Otherwise, I
don't think it's used for anything.

Are there plans to implement other heuristics in SYMPHONY (e.g. RINS) ?
>

Well, there are always plans, but no one to implement them at the moment
:). We worked on RINS a few years ago, but it never made it into the code.
Actually, it may not be that hard to use Cbc's heuristics within SYMPHONY,
although RINS is probably a difficult one to export. If you are interested
in doing some work in this area, I can try to shove you in the right
direction :).

Cheers,

Ted
-- 
Dr. Ted Ralphs
Associate Professor, Lehigh University
(610) 628-1280
ted 'at' lehigh 'dot' edu
coral.ie.lehigh.edu/~ted
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