Re: [Help-glpk] predefined execution time of glpk

[Giorgio Sartor]

Hi Robbie,

please, look at glpk guide first.

If you are solving a MIP problem I suppose you are using glp_intopt instead of glp_simplex.

In that case you have to set up a different parm struct whose name is glp_iocp.

glp_iocp parm;

...

glp_init_iocp(&parm);

parm.tm_lim = 60000;

glp_intopt(MIP, &parm);

...

Best,

Gio

2013/6/19 Robbie Morrison <address@hidden>

Hi John, Andrew, all

------------------------------------------------------------
To:           john tass <address@hidden>
Subject:      Re: [Help-glpk] predefined execution time of glpk
Message-ID:  <address@hidden>
From:         Andrew Makhorin <address@hidden>
Date:         Tue, 18 Jun 2013 12:58:57 +0400
------------------------------------------------------------

>> Is it possible, within a C++ aplication, to
>> predefine a time limit of gkpk execution , and
>> after this time expires to be able of getting
>> the best solution that glpk has found so far ?
>> Is there any command I must include in my C++
>> application? For your information, the linear
>> problem I try to solve is extemely hard and has
>> a very big size. So, I can not affort to wait
>> for its solution but I want the best solution
>> within 60 secs instead.
>
> #include <glpk.h>
> glp_smcp parm;
> . . .
> glp_init_smcp(&parm);
> parm.tm_lim = 60000;
> glp_simplex(P, &parm);
> . . .
>
> For more details please see the glpk reference manual (doc/glpk.pdf)
> included in the distribution.

Just to note, for completeness, that that works
fine for simplex calls, but may not for MIP
calls.  This is because the time limit condition
is only checked when the linear relaxations are
attempted.  In which case, call-backs might be
required for finer-grain control?  Wasn't there a
thread on this issue earlier (I looked but
couldn't find it)?  Or am I totally confused and
mistaken!

cheers, Robbie
---
Robbie Morrison
PhD student -- policy-oriented energy system simulation
Technical University of Berlin (TU-Berlin), Germany
University email (redirected) : address@hidden
Webmail (preferred)           : address@hidden
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