Cutting steel bars for desk legs

    {  Exmpl9.6-1_CuttingSteel.mpl  }

    {  Applications of Optimization with Xpress-MP  }

    {  Chapter 9.6,  Cutting Stell Bars for Desk Legs,  Size: 3x12,  Page 185 }


TITLE
    CuttingSteel;

INDEX
    range := 1..2;
    pattern := 1..12;
    pat1[pattern] := (1,2,3,4,5,6);
    pat2[pattern] := (7,8,9,10,11,12);
    size := (small,medium,large);

DATA
    Length[size] := (0.4,0.6,0.7);
    Dem[size] := (108,125,100);
    Cut[size,pattern] := (0,0,2,0,2,3,0,0,1,3,0,5,
                          0,1,0,2,1,0,1,2,0,0,3,0,
                          2,1,1,0,0,0,2,1,2,1,0,0);
    Len[range] := (1.5,2);
    Loss[pattern] := (10,20,0,30,10,30,0,10,20,10,20,0);

VARIABLE
    BUse[pattern];

MODEL

    MIN TotalLoss = SUM(pattern IN pat1: Len[range:=1] * BUse) + SUM(pattern IN pat2: Len[range:=2] * BUse) - SUM(size: 4 * Dem * Length);

SUBJECT TO

    SatisfyDemand[size] -> SDEM:
        SUM(pattern: BUse * Cut) >= 4 * Dem;

INTEGER
    BUse;

END