Re: [Help-glpk] Controlling Precision of Variable Bounds
On Wed, 2018-04-04 at 11:51 -0400, marky1991 . wrote: > In that case, how am I supposed to know whether that means the > solution's value was 217.351 or 217.3512 (or 217.3511, etc)? Is there > no way to configure this? > Even if you print the solution with more places, please note that the solution itself is computed with a finite relative precision which is about 1e-6 for integer variables. ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
Re: [Help-glpk] Controlling Precision of Variable Bounds
In src/api/prmip.c the output is limited to 6 digits of precision (%13.6g). So this is only an output issue. If you use the GMPL language to specify your problem you can indicate the output precision in the printf statement. Best Regards Heinrich var P, integer >= 0, <=33; var x0, integer, >= 0; var x1, integer, >= 0; var x2, >= 0, <= 217.3512; var x3, integer, >= 0; var x4, integer, >= 0; var x5, integer, >= 0, <= 154; maximize obj: P; s.t. _C1: - 9.8796 * P + 10 * x0 + 10 * x1 + x2 = -108.6756; s.t. _C2: - 7 * P + 7 * x3 + 7 * x4 + x5 = -77; solve; printf "P, %13.12g (%13.12g, %13.12g)\n", P, P.lb, P.ub; printf "x0, %13.12g (%13.12g, %13.12g)\n", x0, x0.lb, x0.ub; printf "x1, %13.12g (%13.12g, %13.12g)\n", x1, x1.lb, x1.ub; printf "x2, %13.12g (%13.12g, %13.12g)\n", x2, x2.lb, x2.ub; printf "x3, %13.12g (%13.12g, %13.12g)\n", x3, x3.lb, x3.ub; printf "x4, %13.12g (%13.12g, %13.12g)\n", x4, x4.lb, x4.ub; printf "x5, %13.12g (%13.12g, %13.12g)\n", x5, x5.lb, x5.ub; end; On 04/04/2018 04:41 PM, marky1991 . wrote: > I'm trying to solve a problem that has noninteger bounds for its > variables, the problem and the outputted solution attached. I'm invoking > glpsol with the command "glpsol --lp parents_allocated-pulp.lp -o > parents_allocated-pulp.sol --mipgap 0.01". > > The trouble is that the upper bound for my "x2" variable is being > limited to "217.351" instead of the given "217.3512" and I'm not sure > why. Is there some parameter I can pass to make it go past 3 decimal > places for the upper bound? > > I tried --exact and every other parameter that I could see but none > helped. Is there some way to increase the number of digits in the bounds? > > My output with 4.65: > > GLPSOL: GLPK LP/MIP Solver, v4.65 > Parameter(s) specified in the command line: > --lp parents_allocated-pulp.lp -o parents_allocated-pulp2.sol --mipgap > 0.01 > Reading problem data from 'parents_allocated-pulp.lp'... > 2 rows, 7 columns, 8 non-zeros > 6 integer variables, none of which are binary > 22 lines were read > GLPK Integer Optimizer, v4.65 > 2 rows, 7 columns, 8 non-zeros > 6 integer variables, none of which are binary > Preprocessing... > 1 row, 2 columns, 2 non-zeros > 2 integer variables, none of which are binary > Scaling... > A: min|aij| = 1.000e+00 max|aij| = 7.000e+00 ratio = 7.000e+00 > Problem data seem to be well scaled > Constructing initial basis... > Size of triangular part is 1 > Solving LP relaxation... > GLPK Simplex Optimizer, v4.65 > 1 row, 2 columns, 2 non-zeros > * 0: obj = 1.1e+01 inf = 0.000e+00 (1) > * 1: obj = 3.3e+01 inf = 0.000e+00 (0) > OPTIMAL LP SOLUTION FOUND > Integer optimization begins... > Long-step dual simplex will be used > + 1: mip = not found yet <= +inf (1; 0) > + 1: > 3.3e+01 <= 3.3e+01 0.0% (1; 0) > + 1: mip = 3.3e+01 <= tree is empty 0.0% (0; 1) > INTEGER OPTIMAL SOLUTION FOUND > Time used: 0.0 secs > Memory used: 0.1 Mb (59394 bytes) > Writing MIP solution to 'parents_allocated-pulp.sol'... > > Thanks for the help. > > > ___ > Help-glpk mailing list > Help-glpk@gnu.org > https://lists.gnu.org/mailman/listinfo/help-glpk > ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
Re: [Help-glpk] Controlling Precision of Variable Bounds
In that case, how am I supposed to know whether that means the solution's value was 217.351 or 217.3512 (or 217.3511, etc)? Is there no way to configure this? ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
Re: [Help-glpk] Controlling Precision of Variable Bounds
On Wed, 2018-04-04 at 10:41 -0400, marky1991 . wrote: > I'm trying to solve a problem that has noninteger bounds for its > variables, the problem and the outputted solution attached. I'm > invoking glpsol with the command "glpsol --lp > parents_allocated-pulp.lp -o parents_allocated-pulp.sol --mipgap > 0.01". > > > The trouble is that the upper bound for my "x2" variable is being > limited to "217.351" instead of the given "217.3512" and I'm not sure > why. Is there some parameter I can pass to make it go past 3 decimal > places for the upper bound? There is nothing wrong. You see 217.351 rather than 217.3512 because glpsol prints the solution report only with 6 decimal places. > > > I tried --exact and every other parameter that I could see but none > helped. Is there some way to increase the number of digits in the > bounds? > > > My output with 4.65: > > GLPSOL: GLPK LP/MIP Solver, v4.65 > Parameter(s) specified in the command line: > --lp parents_allocated-pulp.lp -o parents_allocated-pulp2.sol > --mipgap 0.01 > Reading problem data from 'parents_allocated-pulp.lp'... > 2 rows, 7 columns, 8 non-zeros > 6 integer variables, none of which are binary > 22 lines were read > GLPK Integer Optimizer, v4.65 > 2 rows, 7 columns, 8 non-zeros > 6 integer variables, none of which are binary > Preprocessing... > 1 row, 2 columns, 2 non-zeros > 2 integer variables, none of which are binary > Scaling... > A: min|aij| = 1.000e+00 max|aij| = 7.000e+00 ratio = 7.000e+00 > Problem data seem to be well scaled > Constructing initial basis... > Size of triangular part is 1 > Solving LP relaxation... > GLPK Simplex Optimizer, v4.65 > 1 row, 2 columns, 2 non-zeros > * 0: obj = 1.1e+01 inf = 0.000e+00 (1) > * 1: obj = 3.3e+01 inf = 0.000e+00 (0) > OPTIMAL LP SOLUTION FOUND > Integer optimization begins... > Long-step dual simplex will be used > + 1: mip = not found yet <= +inf(1; 0) > + 1: > 3.3e+01 <= 3.3e+01 0.0% (1; 0) > + 1: mip = 3.3e+01 <= tree is empty 0.0% (0; 1) > INTEGER OPTIMAL SOLUTION FOUND > Time used: 0.0 secs > Memory used: 0.1 Mb (59394 bytes) > Writing MIP solution to 'parents_allocated-pulp.sol'... > > > Thanks for the help. > > ___ > Help-glpk mailing list > Help-glpk@gnu.org > https://lists.gnu.org/mailman/listinfo/help-glpk ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
[Help-glpk] Controlling Precision of Variable Bounds
I'm trying to solve a problem that has noninteger bounds for its variables, the problem and the outputted solution attached. I'm invoking glpsol with the command "glpsol --lp parents_allocated-pulp.lp -o parents_allocated-pulp.sol --mipgap 0.01". The trouble is that the upper bound for my "x2" variable is being limited to "217.351" instead of the given "217.3512" and I'm not sure why. Is there some parameter I can pass to make it go past 3 decimal places for the upper bound? I tried --exact and every other parameter that I could see but none helped. Is there some way to increase the number of digits in the bounds? My output with 4.65: GLPSOL: GLPK LP/MIP Solver, v4.65 Parameter(s) specified in the command line: --lp parents_allocated-pulp.lp -o parents_allocated-pulp2.sol --mipgap 0.01 Reading problem data from 'parents_allocated-pulp.lp'... 2 rows, 7 columns, 8 non-zeros 6 integer variables, none of which are binary 22 lines were read GLPK Integer Optimizer, v4.65 2 rows, 7 columns, 8 non-zeros 6 integer variables, none of which are binary Preprocessing... 1 row, 2 columns, 2 non-zeros 2 integer variables, none of which are binary Scaling... A: min|aij| = 1.000e+00 max|aij| = 7.000e+00 ratio = 7.000e+00 Problem data seem to be well scaled Constructing initial basis... Size of triangular part is 1 Solving LP relaxation... GLPK Simplex Optimizer, v4.65 1 row, 2 columns, 2 non-zeros * 0: obj = 1.1e+01 inf = 0.000e+00 (1) * 1: obj = 3.3e+01 inf = 0.000e+00 (0) OPTIMAL LP SOLUTION FOUND Integer optimization begins... Long-step dual simplex will be used + 1: mip = not found yet <= +inf(1; 0) + 1: > 3.3e+01 <= 3.3e+01 0.0% (1; 0) + 1: mip = 3.3e+01 <= tree is empty 0.0% (0; 1) INTEGER OPTIMAL SOLUTION FOUND Time used: 0.0 secs Memory used: 0.1 Mb (59394 bytes) Writing MIP solution to 'parents_allocated-pulp.sol'... Thanks for the help. parents_allocated-pulp.lp Description: Binary data parents_allocated-pulp.sol Description: Binary data ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
