[Help-glpk] Numerical Instability (Dual and Primal ..)

[Carlos Javier Sosa Gonzalez]

Hello,

I have a "numerical instability" problem in my formulation. I do not know
what is the reason.

I am using the glpk-4.1, and its output is:

lpt_read_prob: reading LP data from `CM162.0.cplex'...
lpt_read_prob: 372 variables, 676 constraints
lpt_read_prob: 955 lines were read
lpx_simplex: original LP has 676 rows, 372 columns, 1856 non-zeros
lpx_simplex: presolved LP has 647 rows, 254 columns, 1678 non-zeros
gm_scal: max / min = 1.000e+06
gm_scal: max / min = 1.000e+06
lpx_adv_basis: size of triangular part = 647
      0:   objval =   0.000000000e+00   infeas =   1.000000000e+00 (0)
     63:   objval =   0.000000000e+00   infeas =   0.000000000e+00 (0)
*    63:   objval =   0.000000000e+00   infeas =   0.000000000e+00 (0)
*   101:   objval =   5.000000000e+00   infeas =   3.144969177e-17 (0)
OPTIMAL SOLUTION FOUND
Integer optimization begins...
Objective function is integral
+   101: mip =     not found yet; lp =   5.000000000e+00 (1, 0)
lpx_simplex: numerical instability (dual simplex)
lpx_simplex: numerical instability (dual simplex)
lpx_simplex: numerical instability (dual simplex)
lpx_simplex: numerical instability (dual simplex)
lpx_simplex: numerical instability (dual simplex)
lpx_simplex: numerical instability (primal simplex, phase II)
lpx_simplex: numerical instability (primal simplex, phase II)
lpx_simplex: numerical instability (dual simplex)
lpx_simplex: numerical instability (primal simplex, phase II)
lpx_simplex: numerical instability (primal simplex, phase II)
lpx_simplex: numerical instability (primal simplex, phase II)
lpx_simplex: numerical instability (primal simplex, phase II)
lpx_simplex: numerical instability (primal simplex, phase II)

Attached, you can find the "CM160.0.cplex" (gzipped).

Thanks in advance,
Javier Sosa

--
 Carlos Javier Sosa González  E.T.S.I. de Telecomunicación
  address@hidden         Campus Universitario de Tafira, Pab. A, Desp. 301 
  Tel.: +34 928 457 324       Univ. de Las Palmas de Gran Canaria
  Fax : +34 928 451 243       35017 Las Palmas de Gran Canaria
  ICQ : 1756350985            Canary Islands. SPAIN

CM162.0.cplex.gz
Description: Binary data