From: Anthony Karageorgos <mcaihak2_at_co.umist.ac.uk>

Date: Tue 22 May 2001 12:18:07 PM GMT

Message-ID: <008101c0e2b9$42f05e10$d6d19284@futures.bt.co.uk>

Date: Tue 22 May 2001 12:18:07 PM GMT

Message-ID: <008101c0e2b9$42f05e10$d6d19284@futures.bt.co.uk>

Dear all, I have obtained ECLiPSe recently. What I need to do is solve a problem similar to the bin packing example described in the fd library documentation. There are some differences, however and the most significant one is the following: In the bin packing example 5 types components (glass, plastic, steel, wood, copper) need to be placed in bins of 3 types (red, blue, green) such as various constraints hold. The example minimises the number of bins of each bin type required to store a given number of components of each component type. The solution is based on a cont(Glass, Plastic, Steel, Wood, Copper)structure (for clarity I am attaching a part of the example below) solve(Bins) :- solve_bin(cont(1, 2, 1, 3, 2), Bins). solve_bin(Demand, Bins) :- Demand = cont(G, P, S, W, C), Sum is G + P + S + W + C, bins(Demand, Sum, [Sum, Sum, Sum, Sum, Sum, Sum], Bins), label(Bins). bins(cont(0, 0, 0, 0, 0), 0, _, []). bins(cont(G0, P0, S0, W0, C0), Sum0, LastBin, [Bin|Bins]) :- Bin = [_Col, G, P, S, W, C], bin(Bin, Sum), G2 #= G0 - G, P2 #= P0 - P, S2 #= S0 - S, W2 #= W0 - W, C2 #= C0 - C, Sum2 #= Sum0 - Sum, ordering(Bin, LastBin), bins(cont(G2, P2, S2, W2, C2), Sum2, Bin, Bins). In my case I do not know the number of component types in advance and therefore I cannot use a similar structure. For example, I would like to have a list of component types and some exclusion constraints described as facts and start from there. How would you reccommend me to model such a problem in order to solve it using ECLiPSe? Many thanks Anthony --------------------------------------- Anthony Karageorgos Room L14 Dept. of Computation UMIST Manchester M60 1QD UK tel. +44-161-2003306 fax. +44-161-2003324 e-mail: mcaihak2@co.umist.ac.ukReceived on Tue May 22 13:24:03 2001

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