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Re: [Help-glpk] Simplex in GLPK and CPLEX in GAMS
From: |
Andrew Makhorin |
Subject: |
Re: [Help-glpk] Simplex in GLPK and CPLEX in GAMS |
Date: |
Mon, 23 Nov 2015 20:46:53 +0300 |
On Mon, 2015-11-23 at 17:45 +0100, Yaser Tohidi wrote:
> Hi
>
>
> I have the attached GAMS file that I can solve in GAMS.
> But when I try to solve the .lp version (attached) by glpk (the c file
> is attached), I receive "LP has no primal feasible solution".
> Please let me know what I can do for solving this in GLPK.
Glpsol has no problem on solving your instance:
GLPSOL: GLPK LP/MIP Solver, v4.57
Parameter(s) specified in the command line:
--lp slave12.lp --log log.txt
Reading problem data from 'slave12.lp'...
16537 rows, 12410 columns, 62455 non-zeros
60540 lines were read
GLPK Simplex Optimizer, v4.57
16537 rows, 12410 columns, 62455 non-zeros
Preprocessing...
11682 rows, 7687 columns, 43956 non-zeros
Scaling...
A: min|aij| = 3.333e-01 max|aij| = 1.000e+07 ratio = 3.000e+07
GM: min|aij| = 1.437e-01 max|aij| = 6.959e+00 ratio = 4.843e+01
EQ: min|aij| = 2.240e-02 max|aij| = 1.000e+00 ratio = 4.465e+01
Constructing initial basis...
Size of triangular part is 11682
0: obj = -6.000000000e+01 inf = 2.420e+06 (1854)
500: obj = -6.000000000e+01 inf = 6.757e+05 (1388) 3
1000: obj = -6.000000000e+01 inf = 2.054e+05 (880) 5
1500: obj = -6.000000000e+01 inf = 5.464e+04 (489) 4
2000: obj = -6.000000000e+01 inf = 1.952e+04 (319) 5
2500: obj = -6.000000000e+01 inf = 1.436e+04 (189) 4
3000: obj = -6.000000000e+01 inf = 9.841e+03 (68) 4
3500: obj = -6.000000000e+01 inf = 5.309e+02 (29) 3
3534: obj = -6.000000000e+01 inf = 1.584e-11 (0)
OPTIMAL LP SOLUTION FOUND
Time used: 6.9 secs
Memory used: 16.2 Mb (16935145 bytes)
> if (glp_get_status(lps12) > 2){
> printf("slave12 status is %d
> which means the problem is infeasible.
> \n",glp_get_status(lps12));
> abort();
> }
To determine the solution status you should use symbolic constants
GLP_OPT, GLP_INFEAS, etc. defined in the glpk.h header rather than
numeric values. (Your code is wrong because GLP_OPT is defined as 5.)
For more details please see the glpk reference manual (doc/glpk.pdf)
included in the distribution tarball.
- Re: [Help-glpk] Simplex in GLPK and CPLEX in GAMS,
Andrew Makhorin <=