Kilroy County

   {  Exmpl9.2-5_KilroyCounty.mpl  }

   {  Winston, Operations Research, Applications and Algorithms, 4th ed.  }

   {  Chapter 9.2,  Example 5,  Set Covering (MIP),  Size: 6x6,  Page 486  }


TITLE
    KilroyCounty;

INDEX
    city := 1..6;
    city2 := city;

DATA
    TravelTime[city,city2] := ( 0,10,20,30,30,20,
                               10, 0,25,35,20,10,
                               20,25, 0,15,30,20,
                               30,35,15, 0,15,25,
                               30,20,30,15, 0,14,
                               20,10,20,25,14, 0);
    MaxTimeDiff := 15;

BINARY VARIABLES
    Build[city];

MODEL

    MIN FireStations = SUM(city: Build);

SUBJECT TO

    Within15Minutes[city] -> WMIN:

        SUM(city2: Build[city:=city2] WHERE (TravelTime <= MaxTimeDiff)) >= 1;

END