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[Help-glpk] LPX overwrite issues, C++ wrapper, version info

From: Robbie Morrison
Subject: [Help-glpk] LPX overwrite issues, C++ wrapper, version info
Date: Fri, 8 Jul 2005 06:30:20 +1200 (NZST)
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Hello <help-glpk>

I am running a year-long simulation (of a national
energy system) which comprises a series of hourly
MILP problems (representing either market clearing
or supervisory control).  The code itself uses the
GLPK API and is fully object-oriented (C++).

I have some questions and would appreciate any

For this simulation, many of the constraint
equations (rows) and variable bounds (ancillary
and structural) will remain unchanged between
solver calls.

In the interest of numerical efficiency, I take it

(1) the LPX problem object should be created only
    once and not destroyed and reestablished for
    each new hourly interval.

And furthermore that:

(2) there is an advantage in not overwriting row
    and bound information where this information
    remains the same as before.

I am also part way through writing a set of "GLPK
interface classes" to allow the user to nominate
which solver to deploy at run-time (simplex,
interior, integer) and then to make the necessary
adjustments in the way the GLPK problem is built
and the solver invoked.  I was wondering if:

(3) anybody has written such a set of classes?


(4) is there any way of knowing the GLPK version
    from within the program?

For instance, would the macros (or similar)
addition to the GLPK API?

Many thanks for the GLPK developers for this
software library.

best wishes

PhD student - policy-oriented energy system simulation
Technical University of Berlin, Germany

Robbie Morrison
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