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Re: [Help-glpk] Suggestions to solve the master problem faster in a Bran
From: |
Andrew Makhorin |
Subject: |
Re: [Help-glpk] Suggestions to solve the master problem faster in a Branch-and-Price model. |
Date: |
Sat, 22 Mar 2014 11:04:06 +0400 |
> Please, add the missing information to glpk.pdf as indicated below:
Okay.
>
> glp_del_rows invalidates the basis factorization.
> glp_del_cols invalidates the basis factorization if the column is basic.
More precisely, any change in the problem object that affects the basis
matrix (adding rows, changing row/column of the constraint matrix, etc.)
invalidates the basis factorization.
> After invalidation of the basis factorization glp_warm_up has to be
> called before calling glp_simplex.
Not needed--glp_simplex does that automatically, if necessary. However,
if the lp preprocessor is used, glp_simplex does not compute the basis
factorization for the original lp at exit.