On Sun, 2020-08-16 at 11:53 +0200, Domingo Alvarez Duarte wrote: > Hello ! > > I just found a class of models that can exhibit a huge memory usage > difference depending on if we add or not add parameter missing values > when there is a default value declaration for then. > > See this model for example > https://github.com/mingodad/GLPK/commit/539dd9774829dee4a0b8c8199a9d2b94a3c7d9cb: > > GLPK-4.65 from pacakage manager 69.85s 3001.9 Mb 1x 1x > > GLPK-4.65 with several optimizations 26.02s 1506.0 Mb 0.37x 0.5x > > GLPK-4.65 prev + no param add missing 16.36s 21.2 Mb Mb 0.23x > 0.007x > > This huge difference is due to this changes > https://github.com/mingodad/GLPK/commit/70d4ad7e97cdb34ee6348c864bd3a941cdb0d422 > > . > > If you have big models/data and can test then with the master branch of > https://github.com/mingodad/GLPK and report your results I would > appreciate it and hope this can lead to more performance improvements in > GMPL/GLPK.
It may not work correctly in some cases, because the expression specified in the default option may recursively refer to elements of the same parameter (directly or indirectly). > > Notice right now the changes mainly affect GMPL model/data generation > not solver/solving the generated problem. > > ==== > > /usr/bin/time glpsol-from-package-manager -m mem-default.mod -d > mem-default.dat > GLPSOL: GLPK LP/MIP Solver, v4.65 > Parameter(s) specified in the command line: > -m mem-default.mod -d mem-default.dat > Reading model section from mem-default.mod... > mem-default.mod:23: warning: unexpected end of file; missing end > statement inserted > 23 lines were read > Reading data section from mem-default.dat... > mem-default.dat:32660: warning: unexpected end of file; missing end > statement inserted > 32660 lines were read > Generating omax... > Generating c1... > Generating c2... > Model has been successfully generated > GLPK Integer Optimizer, v4.65 > 13589 rows, 14037 columns, 42743 non-zeros > 449 integer variables, all of which are binary > Preprocessing... > 9 constraint coefficient(s) were reduced > 4056 rows, 4495 columns, 12792 non-zeros > 448 integer variables, all of which are binary > Scaling... > A: min|aij| = 1.310e-05 max|aij| = 2.660e+02 ratio = 2.031e+07 > GM: min|aij| = 7.228e-02 max|aij| = 1.384e+01 ratio = 1.914e+02 > EQ: min|aij| = 5.224e-03 max|aij| = 1.000e+00 ratio = 1.914e+02 > 2N: min|aij| = 2.620e-03 max|aij| = 1.750e+00 ratio = 6.679e+02 > Constructing initial basis... > Size of triangular part is 4056 > Solving LP relaxation... > GLPK Simplex Optimizer, v4.65 > 4056 rows, 4495 columns, 12792 non-zeros > * 0: obj = 1.000000000e+00 inf = 0.000e+00 (2721) > * 3122: obj = 5.173823646e+02 inf = 0.000e+00 (0) 3 > OPTIMAL LP SOLUTION FOUND > Integer optimization begins... > Long-step dual simplex will be used > + 3122: mip = not found yet <= +inf (1; 0) > + 3122: >>>>> 5.173823646e+02 <= 5.173823646e+02 0.0% (1; 0) > + 3122: mip = 5.173823646e+02 <= tree is empty 0.0% (0; 1) > INTEGER OPTIMAL SOLUTION FOUND > Time used: 0.3 secs > Memory used: 3001.9 Mb (3147772544 bytes) > 69.85user 0.88system 1:10.73elapsed 99%CPU (0avgtext+0avgdata > 3083108maxresident)k > 0inputs+0outputs (0major+770102minor)pagefaults 0swaps > > ==== > > ==== > > /usr/bin/time myglpsol-with-several-optmizations -m mem-default.mod -d > mem-default.dat > GLPSOL: GLPK LP/MIP Solver, v4.65 > Parameter(s) specified in the command line: > -m mem-default.mod -d mem-default.dat > Reading model section from mem-default.mod... > mem-default.mod:23: warning: unexpected end of file; missing end > statement inserted > 23 lines were read > Reading data section from mem-default.dat... > mem-default.dat:32660: warning: unexpected end of file; missing end > statement inserted > 32660 lines were read > Generating omax... > Generating c1... > Generating c2... > Model has been successfully generated > GLPK Integer Optimizer, v4.65 > 13589 rows, 14037 columns, 42743 non-zeros > 449 integer variables, all of which are binary > Preprocessing... > 9 constraint coefficient(s) were reduced > 4056 rows, 4495 columns, 12792 non-zeros > 448 integer variables, all of which are binary > Scaling... > A: min|aij| = 1.310e-05 max|aij| = 2.660e+02 ratio = 2.031e+07 > GM: min|aij| = 7.228e-02 max|aij| = 1.384e+01 ratio = 1.914e+02 > EQ: min|aij| = 5.224e-03 max|aij| = 1.000e+00 ratio = 1.914e+02 > 2N: min|aij| = 2.620e-03 max|aij| = 1.750e+00 ratio = 6.679e+02 > Constructing initial basis... > Size of triangular part is 4056 > Solving LP relaxation... > GLPK Simplex Optimizer, v4.65 > 4056 rows, 4495 columns, 12792 non-zeros > * 0: obj = 1.000000000e+00 inf = 0.000e+00 (2721) > * 3122: obj = 5.173823646e+02 inf = 0.000e+00 (0) 3 > OPTIMAL LP SOLUTION FOUND > Integer optimization begins... > Long-step dual simplex will be used > + 3122: mip = not found yet <= +inf (1; 0) > + 3122: >>>>> 5.173823646e+02 <= 5.173823646e+02 0.0% (1; 0) > + 3122: mip = 5.173823646e+02 <= tree is empty 0.0% (0; 1) > INTEGER OPTIMAL SOLUTION FOUND > Time used: 0.3 secs > Memory used: 1506.0 Mb (1579147056 bytes) > 26.02user 0.57system 0:26.61elapsed 99%CPU (0avgtext+0avgdata > 1547792maxresident)k > 1952inputs+0outputs (9major+386354minor)pagefaults 0swaps > > ==== > > ==== > > /usr/bin/time myglpsol-master -m mem-default.mod -d mem-default.dat > GLPSOL: GLPK LP/MIP Solver, v4.65 > Parameter(s) specified in the command line: > -m mem-default.mod -d mem-default.dat > Reading model section from mem-default.mod... > mem-default.mod:23: warning: unexpected end of file; missing end > statement inserted > 23 lines were read > Reading data section from mem-default.dat... > mem-default.dat:32660: warning: unexpected end of file; missing end > statement inserted > 32660 lines were read > Generating omax... > Generating c1... > Generating c2... > Model has been successfully generated > GLPK Integer Optimizer, v4.65 > 13589 rows, 14037 columns, 42743 non-zeros > 449 integer variables, all of which are binary > Preprocessing... > 9 constraint coefficient(s) were reduced > 4056 rows, 4495 columns, 12792 non-zeros > 448 integer variables, all of which are binary > Scaling... > A: min|aij| = 1.310e-05 max|aij| = 2.660e+02 ratio = 2.031e+07 > GM: min|aij| = 7.228e-02 max|aij| = 1.384e+01 ratio = 1.914e+02 > EQ: min|aij| = 5.224e-03 max|aij| = 1.000e+00 ratio = 1.914e+02 > 2N: min|aij| = 2.620e-03 max|aij| = 1.750e+00 ratio = 6.679e+02 > Constructing initial basis... > Size of triangular part is 4056 > Solving LP relaxation... > GLPK Simplex Optimizer, v4.65 > 4056 rows, 4495 columns, 12792 non-zeros > * 0: obj = 1.000000000e+00 inf = 0.000e+00 (2721) > * 3122: obj = 5.173823646e+02 inf = 0.000e+00 (0) 3 > OPTIMAL LP SOLUTION FOUND > Integer optimization begins... > Long-step dual simplex will be used > + 3122: mip = not found yet <= +inf (1; 0) > + 3122: >>>>> 5.173823646e+02 <= 5.173823646e+02 0.0% (1; 0) > + 3122: mip = 5.173823646e+02 <= tree is empty 0.0% (0; 1) > INTEGER OPTIMAL SOLUTION FOUND > Time used: 0.2 secs > Memory used: 21.2 Mb (22256384 bytes) > 16.36user 0.02system 0:16.39elapsed 99%CPU (0avgtext+0avgdata > 24516maxresident)k > 2600inputs+0outputs (11major+7226minor)pagefaults 0swaps > > ==== > > Cheers ! > > >
