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[Help-glpk] spx_simplex: numerical instability (primal simplex, phase I)
From: |
rockwell |
Subject: |
[Help-glpk] spx_simplex: numerical instability (primal simplex, phase I) and infinite looping in glpk on large model |
Date: |
Wed, 4 Apr 2007 02:05:04 +0400 |
glpk-help,
I am attaching 3 versions of the same model that differe in their
limits on two rows. KnockoutRow and KnockoutRow_up
All versions of the model display the error:
spx_simplex: numerical instability (primal simplex, phase I)
However the version ec_kn10_kca_mps.txt loops infinitely
Also all column ending in _kcol are intended to be integer (actualy
binary as their lower limit = 0 and upper limit = 1)).
I am attaching the output as well.
I have tried scaling my objective function (which has a coeffecent of
1) by small numbers and scalling my limits as well but neither approach
has helped remove the instabilities.
Graham Rockwell
ec_kn0_kc0_mps.txt created error1.txt
ec_kn10_kca_mps.txt created error2.txt
(I removed attachments, since they are very large. - Andrew Makhorin.)
- [Help-glpk] spx_simplex: numerical instability (primal simplex, phase I) and infinite looping in glpk on large model,
rockwell <=