Andrew, > I tried solving it in the following way. First I used --bestp to find a > feasible solution quickly and save it to a file: ... > And then I used that solution as an incumbent value trying to "prove" > its optimality:
This is essentially what --proxy does when searching for a first solution. However this doesn't work now, while in the previous version it was finding solutions. I added the line: #define glp_term_out(x) x at the beginning of proxy.c and found this: [...] Applying PROXY heuristic... Proxy's time limit set to 60 seconds. Proxy's relative improvement set to 1.00 %. Searching for a feasible solution... GLPK Simplex Optimizer, v4.59 394 rows, 321 columns, 1213 non-zeros * 0: obj = 8.685404001e+004 inf = 0.000e+000 (0) OPTIMAL LP SOLUTION FOUND GLPK Integer Optimizer, v4.59 394 rows, 321 columns, 1213 non-zeros 154 integer variables, all of which are binary Integer optimization begins... + 0: mip = not found yet >= -inf (1; 0) Warning: numerical instability (dual simplex, phase II) 242500: obj = 2.414880323e+009 inf = 7.186e+007 (25) 243000: obj = 2.414880323e+009 inf = 7.186e+007 (25) 243500: obj = 2.414880323e+009 inf = 7.186e+007 (25) 244000: obj = 2.414880323e+009 inf = 7.186e+007 (25) [...] This was with just "glpsol --proxy water.mps" and is essentially the same failure as the one I reported earlier: >> + 86090: mip = not found yet >= 1.160667584e+005 (3265; 251) >> Warning: numerical instability (dual simplex, phase II) >> 294000: obj = 3.121033256e+008 inf = 5.425e+006 (14) >> 294500: obj = 3.121033256e+008 inf = 5.425e+006 (14) >> 295000: obj = 3.121033256e+008 inf = 5.425e+006 (14) >> 295500: obj = 3.121033256e+008 inf = 5.425e+006 (14) >> 296000: obj = 3.121033256e+008 inf = 5.425e+006 (14) >> 296500: obj = 3.121033256e+008 inf = 5.425e+006 (14) Best Regards, Chris Matrakidis _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
