[Help-glpk] [Fwd: How can regions be modeled in which different objective functions apply?]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Thomas Schwabhäuser <address@hidden>
To: address@hidden
Subject: How can regions be modeled in which different objective
functions apply?
Date: Thu, 28 Sep 2017 11:02:48 +0200

Dear All --

 


I need to find the maximum energy which is given by 4 GMPL expressions
F[x,y], G[x,y], H[x,y], K[x,y], say. These expressions apply to
different regions determined by thresholds S and T. According to Re:
[Help-glpk] Multiple LP problem solving I was going to solve the
following Problem:
 

     maximize Energy: ObjF;

 

     subject to Region1: x >= S or y >= T or ObjF <= F[x,y] ;

     subject to Region2: x <= S or y >= T or ObjF <= G[x,y];

     subject to Region3: x >= S or y <= T or ObjF <= H[x,y];

     subject to Region4: x <= S or y <= T or ObjF <= K[x,y];

 

Unfortunately the Messages when parsing this are

 

Reading model section from models\RLMF.mod...

models\Regions.mod:79: syntax error in constraint statement

Context: ...ize Energy : Z ; subject to Region1 : XM >= Thresh_M or

 

     1. Can somebody explain this error?
     2. I suspect a logical or is not allowed in constraints. Is that
        true?
     3. If so, could anybody propose an alternative?

 

Thanks, Thomas