[Coin-discuss] SYMPHONY speedup

[Jack Bryan]

Thanks, 

If I use SYMPHONY solver to solve the same mILP models on the same hardware platform,
how much speedup I can get ?

For example, if I solve the same MILP model with one CPU, and then I solve it with 
10 CPUs, how much the average speedup I can get ?

"Average" means that the average speedup of 10 or 20 MILP models.

Are there some papers that use SYMPHONY as a paralle solver and show some results ?  

I need to know these results before I decide whether I need parallel SYMPHONY to solve 
large milp models that may take more than 15 minutes.

thanks

Jack

April 22  2009 

> Date: Wed, 22 Apr 2009 10:16:48 +0200
> From: achterberg at zib.de
> To: dtustudy68 at hotmail.com
> CC: coin-discuss at list.coin-or.org
> Subject: Re: [Coin-discuss] SYMPHONY speedup
> 
> Hi Jack,
> 
> for MILP, your question cannot be answered (LP is a different story). Parallel speedup and
> performance difference accross different solvers depend on the model.
> 
> For example, there are models that can be solved by solver A in less than a second but
> that take forever by another solver B, just because solver B is lacking the important
> feature (like a cutting plane or a presolving reduction) to solve this particular model.
> And there may be other models for which the situation is reversed. Finally, there are
> models that can be solved in roughly the same time by all branch-and-cut MILP solvers.
> 
> Overall, my experience is that the algorithmic quality of a solver is usually much more
> important than parallelization. This means, that often solvers like CBC, SCIP, Gurobi,
> XPress, or CPLEX will be faster than Symphony, even if you use 1000 CPUs for Symphony.
> But, as I said, some models do not require the sophisticated machinery that these solvers
> provide and parallelize well. In this setting, Symphony can be really great if you have
> access to a massively parallel computing environment.
> 
> So, the short answer is: you just need to test it for your models. You cannot say in advance.
> 
> 
> Cheers,
> 
> Tobias
> 
> Jack Bryan wrote:
> > Hi ,
> > 
> > I am a new user of SYMPHONY .
> > 
> > I need to use it to solve very large mixed integer linear programming 
> > models.
> > 
> > So, I need to use PVM for SYMPHONY .
> > 
> > But, I do not know how much speed up I can get from the parallel SYMPHONY ?
> > 
> > For example, if it takes 100 seconds to solve a MILP model in CPLEX, how
> > long to solve it in SYMPHONY ?
> > 
> > 
> > thanks
> > 
> > Jack
> > 
> > April 21  2009
> > 
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