Originally posted by: OverflowChu

Hello,

Does anyone know how to define a variable x[ i ][ j ]where i <= j in IBM ILOG CPLEX Studio?

I tried for example

range j = 0..10;

range i=0..j;

dvar float x[ i ][ j ];

but didn't work. I don't want to use a tuple as others suggested

tuple T { int i; int j; };

{T} tuples = { <i,j> | i,j in I : i<=j };

dvar float x[tuples];}

because I'd like to keep my variable in the format of x[ i ] [ j ] instead of x[ i ].

Thanks in advance.

Hi,

you could use dexpr for that:

range I = 0..10;

tuple T { int i; int j; };

{T} tuples = { <i,j> | i,j in I : i<=j };

dvar float y[tuples];

dexpr float x[i in I,j in I]=y[<i,j>];

subject to
{
x[1,2]<=4;
}

regards