Hi Andrew and other API users An update.
I modified my problem generator to remove an 'aphysical' mistake -- namely transmission lines with negative losses (which, I suppose, is equivalent to letting them suck in power from the aether). This fix also corrected the minimization flag problem I had early experienced (and which was reported in my last posting). But even so, the flag problem still seems strange. I don't see how the physicality of the problem could be an issue. Should anyone wish to investigate this further, I am willing to write the original model out as a set of sequential GLPK calls. But this is quite some work, so I would need an expression of interest. with best wishes Robbie > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 25 Jun 2008 18:50:47 +0400 > From: Robbie Morrison <[EMAIL PROTECTED]> > Subject: [Bug-glpk] minimization flag ignored by 'glp_simplex' (GLPK > 4.25) > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=us-ascii > > > Hello Andrew and other API users > > I am using GLPK 4.25 (because my transition to 4.28 has > not yet been completed for the reasons outlined in my > posting on 06-Jun-2008). > > I am currently experiencing a problem getting > 'minimization' to stick, even though I set this flag > explicitly with 'glp_set_obj_dir' and 'glp_get_obj_dir' > returns 'GLP_MIN' before and after the solver call. > > I have some small test LPs (nodal electricity markets > as it happens), ranging in size from 4x4 to 100x70, and > the problem only occurs when I invoke 'glp_simplex'. > If I switch to 'lpx_interior' instead, everything works > EXACTLY as expected. [snip - remainder of post] -- Robbie Morrison Technical University of Berlin, Berlin, Germany University email (redirected) : [EMAIL PROTECTED] Webmail (preferred) : [EMAIL PROTECTED] [from IMAP client] _______________________________________________ Bug-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-glpk
