034: Warehouse Location Problem

language ESSENCE 1.2.0
$ prob034.essence: Warehouse Location Problem
$ Problem details available at http://www.csplib.org/Problems/prob034/
$ 07 September 2007
$

given n_stores, n_warehouses : int(1..)

letting Store be domain int(1..n_stores),
        WHouse be domain int(1..n_warehouses)

given capacity : function (total) WHouse --> int(1..),
      opencost : function (total) WHouse --> int(1..),
      cost : function (total) tuple (Store, WHouse) --> int(1..)

find open : function (total) Store --> WHouse

minimising (sum r in range(open). opencost(r)) + sum s : Store . cost((s,open(s)))

such that forAll w : WHouse . |preImage(open,w)| <= capacity(w)