GAMS World Forum

Hello all,

I am quite new to forum and a beginner to GAMS.

I want to form the equation attached. https://image.ibb.co/c41Qpb/equation.png
I already introduced the i,j and k to the software however when i add the order of (k-1) at the LHS of the equation it gives Error 170 Domain violation for element when i want to introduce the equation. What should i do to manipulate the k index as i want?

I tried these two:

• function(i,j,k) .. x(i,j,'k-1')-x(i,j,k)=l=s(i,j,k)

• function(i,j,'k-1',k) .. x(i,j,'k-1')-x(i,j,k)=l=s(i,j,k)

Hi
Just write k-1 without the quotation marks. Note that you have to start at the second element of k, so you can add a $-restriction on the function:

function(i,j,k)$(ord(k) > 1) .. x(i,j,k-1) - x(i,j,k) =l= s(i,j,k)

Cheers
Renger