I'm not entirely sure I understand this, but if you are saying that
you want to fix DEMANDS_pd at zero for all cells not covered by the
other two constraints, what about the following?
subject to fix_zero {i in NODES, j in NODES, k in NODES, m in NODES :
m <> i || (k <> i && k <> j)}:
DEMANDS_pd[i,j,k,m] = 0;
On Jul 2, 7:11 am, plozmar <
lozano_pal...@...> wrote:
> Hi,
>
> I have a big problem trying to find a good constraint for the
> following case:
>
> ---------------------------------------
> param DEMANDS{NODES};
>
> var DEMANDS_pd {NODES, NODES, NODES, NODES};
>
> subject to demands_per_node_per_demand {i in NODES, j in NODES}:
>
> DEMANDS_pd [i,j,j,i] = DEMANDS [i,j];
>
> subject to demands_per_node_per_demand_2 {i in NODES, j in NODES}:
>
> DEMANDS_pd [i,j,i,i] = -DEMANDS[i,j];
> -------------------------------------------
>
> The result variable DEMANDS_pd has the following apparence, for
> example, for DEMANDS_pd[1,2,*,*]
>
> 1 2 3 4
> 1 0.5 0 0 0
> 2 -0.5 0 0 0
> 3 0 0 0 0
> 4 0 0 0 0
>
> this table MUST have only two elements different from zero (the same
> but opposite). I need a constraint that fixes the values of all the
> elements a zero because with another contraints, the values can
> change, and change all the result...
>
> Thank you very much in advance,
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