GAMS_sample.gms

Set
  i   "Project"  / 1*8 /
  j   "Atributes" / person_weeks, labors, crane, profit, perm /;

Table p1(i, j) "Parameters for the problem"
        person_weeks          labors          crane          profit      perm
1               8               6              1              80          70
2              12               5              0             110          80
3              13               4              1             100          50
4              11               7              0              90          30
5               9               8              0              70          70
6               7               3              1              80          80
7               8               4              1              90          60
8               8               5              1              60          40;

Variables
  x(i)    "Choose a project or not"
  z       "Total profit (in thousands)"
  zp      "Total profil considering maximin";
Binary Variable x;
Equations
  earning "Total earning"
  earningp "For maximin case"
  weeks   "Total preparation time, person-weeks"
  labors  "Total skilled labors"
  cranes  "Number of cranes";

earning .. z  =e= sum(i, p1(i, "profit") * x(i));
earningp.. zp =e= sum(i, p1(i, "perm") * x(i));

weeks   .. 50 =g= sum(i, p1(i, "person_weeks") * x(i));
labors  .. 30 =g= sum(i, p1(i, "labors") * x(i));
cranes  .. 3  =g= sum(i, p1(i, "crane") * x(i));

Model construction /earning,weeks,labors,cranes/ ;
Solve construction using MIP maximizing z ;

Display x.l, z.l;


Model maximin /earningp,weeks,labors,cranes/ ;
Solve maximin using MIP maximizing zp;

Display x.l, zp.l;