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Re: [Help-glpk] Basis read/write
From: |
Andrew Makhorin |
Subject: |
Re: [Help-glpk] Basis read/write |
Date: |
Tue, 15 Dec 2009 07:57:56 +0300 |
> While I understand the reason why these features were removed, I was
> wondering whether these are scheduled to be re-introduced (without the
> limitations listed by Andrew of course) sometime in future.
> The one release post my last mail (4.40) does not have these.
Still not, sorry.
I see three reasons you need to save the basis in a file:
a) you would like to run an LP which has been solved just to
reproduce results (for example, to debug printing report in
MathProg model). In this case you can use the options
'-w filename' / '-r filename';
b) you would like to process the file with another application.
Again, you can use the options -w/-r;
c) you would like to solve a similar LP using the basis saved
as a starting point. Currently it is impossible, because glpk
has no feature to construct a similar basis. However, if that
similar LP has *exactly* the same set of rows and columns as
the original one (for example, only some constraint/objective
coefficients were changed), you can use the options -w/-r.