Jip J. Dekker
f2a1c4e389
git-subtree-dir: software/mza git-subtree-split: f970a59b177c13ca3dd8aaef8cc6681d83b7e813
63 lines
1.4 KiB
MiniZinc
63 lines
1.4 KiB
MiniZinc
% RUNS ON mzn20_fd
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% RUNS ON mzn-fzn_fd
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% RUNS ON mzn20_fd_linear
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% RUNS ON mzn20_mip
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%------------------------------------------------------------------------------%
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% cutstock.mzn
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% Jakob Puchinger <jakobp@cs.mu.oz.au>
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% December 2007
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% vim: ft=zinc ts=4 sw=4 et tw=0
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%
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% The cutting stock problem: Kantorovitch formulation for colgen.
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%
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%------------------------------------------------------------------------------%
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int: L; % stock length
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int: K; % upper bound on number of stock pieces
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int: N; % number of stock pieces
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array[1..N] of int: i_length;
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array[1..N] of int: i_demand;
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array[1..K] of var 0..1: pieces;
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array[1..K, 1..N] of var int: items;
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constraint
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forall(k in 1..K, i in 1..N)( items[k,i] >=0 );
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solve ::int_search(array1d(1..K*N,items)++pieces,input_order,indomain_min,complete) minimize
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sum([ pieces[k] | k in 1..K]);
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constraint
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forall(i in 1..N)
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(
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sum( [ items[k, i] | k in 1..K] ) >= i_demand[i]
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);
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constraint
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forall( k in 1..K ) (
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sum(i in 1..N)( items[k,i] * i_length[i] ) <= pieces[k] * L
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);
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% required for showing the objective function
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var int: obj;
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constraint
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obj = sum([ pieces[k] | k in 1..K]);
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output
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[ "Cost = ", show( obj ), "\n" ] ++
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[ "Pieces = \n\t" ] ++ [show(pieces)] ++ [ "\n" ] ++
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[ "Items = \n\t" ] ++
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[ show(items[k, i]) ++ if k = K then "\n\t" else " " endif |
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i in 1..N, k in 1..K ] ++
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[ "\n" ];
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% data:
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N = 3;
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K = sum(i_demand);
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L = 10;
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i_length = [7, 5, 3];
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i_demand = [2, 2, 4];
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