[Symphony] Help/Feature request

[Haroldo Santos]

On Sun, Oct 30, 2011 at 1:53 PM, Ted Ralphs <ted at lehigh.edu> wrote:

>
>
> 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?
>
Ok, I'll try it.

>
>
>> 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.
>
There are some MIP heuristics which consider information from a pool of
solutions (e.g.: crossing, implemented in CBC).


> 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 :).
>
 Yes, I'm interest in coding some MIP heuristics and integrating them in
SYMPHONY would be great. I'll read more about symphony organization and
contact you as soon as I have a better understanding of how it works.

Meanwhile, if you have some pointer to indicate me on where to start...


> Cheers,
>
> Ted
> --
> Dr. Ted Ralphs
> Associate Professor, Lehigh University
> (610) 628-1280
> ted 'at' lehigh 'dot' edu
> coral.ie.lehigh.edu/~ted <http://coral.ie.lehigh.edu/%7Eted>
>
>


-- 
=============================================================
Haroldo Gambini Santos
Computing Department - Universidade Federal de Ouro Preto - UFOP
email: haroldo [at ] iceb.ufop.br
home/research page: www.decom.ufop.br/haroldo/

"Computer science is no more about computers than astronomy
is about telescopes." Edsger Dijkstra
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