Conditional Statment

GAMS
1

Dear All,

Kindly I would like to know how to write the below conditional statement in GAMS
image.png
Is just make yij and vi binary variables?

Thanks in advance

2

No. You also have to link binary variables with x.

I assume arc (i, j) is used means that x(i, j) > 0
similarly node i is used means either x(i, j) or x(j, i) is nonzero for all j that connect to node i.

You can do this using a big-M formulation.

  • Atharv
3

Dear Atharv,

Thanks a lot for your suggestion

I used the big M method as you told me, would you please confirm to me if I’m writing it correctly?
<
Scaler bigM /1000/;

Binary Variable
y(i,j)
v(i);

Equations
VBinC1 “1, if node i is used”
VBinC2 “0, Otherwise” ;

VBinC1(i,j)… x(i,j) =l= bigMv(i);
VBinC2(i,j)… x(i,j) =g= 1e-6 - bigM(1-v(i));>
image.png