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Re: [Help-glpk] what does it mean by "Numerically instability"

From: glpk xypron
Subject: Re: [Help-glpk] what does it mean by "Numerically instability"
Date: Fri, 08 Oct 2010 00:00:26 +0200

Hello Xiaomi,

if the basic solution is not primal/dual feasible within a tolerance
the warning you observed is written.

The tolerances are passed in structure glp_smcp to the simplex solver
as fields tol_bnd and tol_dj, both defaulting to 1e-7.

This may be caused by bad scaling of the model, e.g. excessive
values of M in a big M approach.


Best regards


-------- Original-Nachricht --------
> Datum: Thu, 7 Oct 2010 13:48:56 -0400
> Betreff: [Help-glpk] what does it mean by "Numerically instability"

> When I solve the LP file in GLPK 4.44, there are multiple same warnings:
> Numerically instability (primal simplex, phase I)
> What does that mean? Thanks.
> _______________________________________________
> Help-glpk mailing list
> address@hidden

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