Originally posted by: 18125514

How to define the decision variable x[i][j][k] such that i！= j.

Without the tuple.

Just like：

dvar boolean x[i in A][j in A:j!=i][Trucks]

？？？

When I only define the decision variable x[i][j][k] the result remind me

"has never been used ### by engine"

Hi,

indeed all dimensions of a multi dimension dvar array should be fixed and cannot depend of a previous dimension.

So the only way for you would be to use a tuple.

Here you should write

dvar boolean x[i in A][j in A][Trucks]

and indeed you ll get a warning about not used decision variables

regards