Gritting Roads

    {  Exmpl15.4-1_GrittingCircuit.mpl  }

    {  Applications of Optimization with Xpress-MP  }

    {  Chapter 15.4,  Gritting Roads,  Size: 42x32,  Page 325 }


TITLE
    GrittingCircuit;

INDEX
    isec := 1..12;
    isec2 := isec;

DATA
    Len[isec,isec2] := [1,2,150,1,5,165,
                        2,3,130,2,5,230,2,6,160,
                        3,2,140,3,4,100,
                        4,3,100,4,8,190,
                        5,1,165,5,6,144,
                        6,2,170,6,5,144,6,7,128,6,9,218,6,10,174,
                        7,3,200,7,6,122,7,8,109,7,11,185,
                        8,4,180,8,11,141,8,12,190,
                        9,5,194,9,10,148,
                        10,6,174,10,7,233,
                        11,7,185,11,10,135,
                        12,11,110];

VARIABLE
    VUse[isec,isec2] WHERE (Len > 0);

MODEL

    MIN Length = SUM(isec,isec2: Len * VUse);

SUBJECT TO

    BalanceFlow[isec] -> FBAL:
        SUM(isec2: VUse) = SUM(isec2: VUse[isec:=isec2,isec2:=isec]);

    GritEveryStreet[isec,isec2] -> GSTR:
        VUse >= 1;

END