Hello Andrew, all ------------------------------------------------------------ To: Reginald Beardsley <[email protected]> Subject: Re: [Help-glpk] Multithreading/parallelization Message-ID: <1355723358.2056.14.camel@corvax> From: Andrew Makhorin <[email protected]> Date: Mon, 17 Dec 2012 09:49:18 +0400 ------------------------------------------------------------
> Though parallelization allows reducing the > solution time, in my opinion, it is a brute > force approach (at least for problems which glpk > is intended to solve); moreover, since in case > of hard mips the solution time grows > exponentially, this approach helps not so much > (until you have 2**n processors, where n is the > number of integer variables :). It seems to me > that algorithmic solutions are able to provide > much greater performance. This email is pretty much a repeat of my posting on 04 Sep 2012, archived at: http://lists.gnu.org/archive/html/help-glpk/2012-09/msg00010.html Figure 4 (p120) in Koch etal (2012) supports Andrew's view. Proprietary solvers on multiple cores often performed *very much* worse in terms of elapsed time, nodes explored, and memory consumption. It looks like multi-core hardware only starts to pay off over about 16 cores. Koch, Thorsten, Tobias Achterberg, Erling Andersen, Oliver Bastert, Timo Berthold, Robert E Bixby, Emilie Danna, Gerald Gamrath, Ambros M Gleixner, Stefan Heinz, Andrea Lodi, Hans Mittelmann, Ted Ralphs, Domenico Salvagnin, Daniel E Steffy, and Kati Wolter. 2011. MIPLIB 2010 : mixed integer programming library version 5. Mathematical Programming Computation v3 no2 p103-163. doi:10.1007/s12532-011-0025-9 http://mpc.zib.de/index.php/MPC/article/viewFile/56/28 Robbie --- Robbie Morrison PhD student -- policy-oriented energy system simulation Technical University of Berlin (TU-Berlin), Germany University email (redirected) : [email protected] Webmail (preferred) : [email protected] [from Webmail client] _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
