On Windows 32bit the problem is also solved after a few iterations. Hence this is not a problem depending on the bitness of the system.
On Linux 32 bit solving problem is not completed with default settings. But the problem is solved at short notice with: glpsol --lp input.cplex --first Best regards Xypron > -------- Forwarded Message -------- > From: Horst Schirmeier <[email protected]> > To: [email protected] > Subject: Simplex termination 32 vs. 64 bit > Date: Sat, 7 Apr 2012 18:56:09 +0200 > > Hi, > > for the attached CPLEX-format ILP I'm observing a different termination > behaviour on 32-Bit (doesn't terminate within the observed time frame of > several hours) vs. 64-Bit (terminates after 0.4s) Linux. I'm running > unpatched glpsol 4.47 (.tar.gz taken from gnu.org, built from sources) > on Debian 6.0: > > Debian 6.0, 32-Bit: > $ glpsol --lp input.cplex > GLPSOL: GLPK LP/MIP Solver, v4.47 > Parameter(s) specified in the command line: > --lp input.cplex > Reading problem data from `input.cplex'... > 332 rows, 2301 columns, 6903 non-zeros > 2301 integer variables, all of which are binary > 7228 lines were read > GLPK Integer Optimizer, v4.47 > 332 rows, 2301 columns, 6903 non-zeros > 2301 integer variables, all of which are binary > Preprocessing... > 314 rows, 2301 columns, 4602 non-zeros > 2301 integer variables, all of which are binary > Scaling... > A: min|aij| = 1.000e+00 max|aij| = 3.000e+00 ratio = 3.000e+00 > Problem data seem to be well scaled > Constructing initial basis... > Size of triangular part = 314 > Solving LP relaxation... > GLPK Simplex Optimizer, v4.47 > 314 rows, 2301 columns, 4602 non-zeros > 0: obj = 3.372000000e+03 infeas = 2.430e+02 (0) > * 315: obj = 3.153000000e+03 infeas = 0.000e+00 (0) > * 500: obj = 1.321000000e+03 infeas = 1.092e-15 (0) > * 851: obj = 5.020000000e+02 infeas = 7.401e-17 (0) > OPTIMAL SOLUTION FOUND > Integer optimization begins... > + 851: mip = not found yet >= -inf (1; 0) > + 1437: >>>>> 5.040000000e+02 >= 5.020000000e+02 0.4% (50; 0) > + 1631: >>>>> 5.030000000e+02 >= 5.020000000e+02 0.2% (65; 21) > + 40041: mip = 5.030000000e+02 >= 5.020000000e+02 0.2% (51; 2232) > + 76140: mip = 5.030000000e+02 >= 5.020000000e+02 0.2% (137; 4202) > +116304: mip = 5.030000000e+02 >= 5.020000000e+02 0.2% (116; 6415) > [... continues for hours without ever terminating ...] > > Debian 6.0, 64-Bit: > $ glpsol --lp input.cplex > GLPSOL: GLPK LP/MIP Solver, v4.47 > Parameter(s) specified in the command line: > --lp input.cplex > Reading problem data from `input.cplex'... > 332 rows, 2301 columns, 6903 non-zeros > 2301 integer variables, all of which are binary > 7228 lines were read > GLPK Integer Optimizer, v4.47 > 332 rows, 2301 columns, 6903 non-zeros > 2301 integer variables, all of which are binary > Preprocessing... > 314 rows, 2301 columns, 4602 non-zeros > 2301 integer variables, all of which are binary > Scaling... > A: min|aij| = 1.000e+00 max|aij| = 3.000e+00 ratio = 3.000e+00 > Problem data seem to be well scaled > Constructing initial basis... > Size of triangular part = 314 > Solving LP relaxation... > GLPK Simplex Optimizer, v4.47 > 314 rows, 2301 columns, 4602 non-zeros > 0: obj = 3.372000000e+03 infeas = 2.430e+02 (0) > * 315: obj = 3.153000000e+03 infeas = 0.000e+00 (0) > * 500: obj = 1.488000000e+03 infeas = 0.000e+00 (0) > * 844: obj = 5.020000000e+02 infeas = 8.327e-17 (0) > OPTIMAL SOLUTION FOUND > Integer optimization begins... > + 844: mip = not found yet >= -inf (1; 0) > + 2394: >>>>> 5.040000000e+02 >= 5.020000000e+02 0.4% (42; 0) > + 3560: >>>>> 5.030000000e+02 >= 5.030000000e+02 0.0% (37; 88) > + 3560: mip = 5.030000000e+02 >= tree is empty 0.0% (0; 171) > INTEGER OPTIMAL SOLUTION FOUND > Time used: 0.4 secs > Memory used: 2.1 Mb (2252288 bytes) > > The input data is attached to this email. Is it somewhat malformed, or > did I indeed step on a GLPK bug? > > Kind regards, > Horst Schirmeier > -- Follow me at http://twitter.com/#!/xypron Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de _______________________________________________ Bug-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/bug-glpk
