Hello all Earlier Andrew Makhorin wrote (in relation to a Sudoku problem) (Message-ID: <[EMAIL PROTECTED]>):
> Try using the option '--intopt' to enable the > mip presolver. It may reduce the problem size by > removing redundant rows and columns. I am working on a relatively literal energy system simulation. Part of the model involves interconnected units transacting electricity, natural gas, district heat, and so on. Ultimately a (directed acyclic) patchwork of classical network flow problems needs to be solved -- together with a refinement to avoid low duty (less than say 50%) usage which thereby introduces binary variables to cover the shut-down status. The simulation generates a suitable GLPK problem using the GLPK C-language APIs. It would make my C++ coding easier if I could populate this model with a lot of trivial constraint equations which simply match the flows between units. For instance: flow-from-generator = flow-to-transmission-line Is this sensible or would I be better advised to be resolve these variables before building the GLPK problem? Or will the following setting (GLPK 4.11 API) reduce the problem automatically: lpx_set_int_parm(my_lpx, LPX_K_PRESOL, 1); And will I need to introduce some special variables to cover gas supply from Russia? :-) many thanks in advance Robbie ps: the compile-time (and to a lesser extent the run-time) version information will also be useful for this project, hence looking forward to using 4.16, thanks! --- Robbie Morrison PhD student -- policy-oriented energy system simulation Institute for Energy Engineering (IET) Technical University of Berlin (TU-Berlin), Germany [from IMAP client] _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
