77 lines
2.1 KiB
MiniZinc
77 lines
2.1 KiB
MiniZinc
% RUNS ON mzn20_fd
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% RUNS ON mzn-fzn_fd
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% RUNS ON mzn20_mip
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% Regression test for bug #335.
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% Previous versions of CPX found this model to be unsatisfiable.
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% A slightly later version found a solution but it was not optimal
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% (stime = 11, rather than the optimal stime = 9.)
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int: w; % width of board
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int: n; % board positions 1, ..., w, w+1, ...., 2w, ...,
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constraint assert(n mod w == 0, "board must be rectangular");
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set of int: POS = 1..n;
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int: stps; % max steps in solution
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set of int: STEPS = 1..stps;
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int: nw; % number of walls
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set of int: WALLS = 1..nw;
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array[WALLS] of POS: walls; % wall positions
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int: nc; % number of crates + goals
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set of int: CRATES = 1..nc;
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set of POS: goals; % goal positions;
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array[CRATES] of POS: crates; % initial crate positions
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POS: pInit; % initial sokoban position
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set of int: MOVES = {-w,-1,1,w}; % possible moves
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include "alldifferent.mzn";
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array[STEPS] of var POS: sokPosn; % sokoban position
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array[STEPS] of var MOVES: move; % sokoban position
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array[STEPS,CRATES] of var POS: cratePosns;
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var STEPS: stime; % time of solution
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%% initial positions
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constraint sokPosn[1] = pInit;
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constraint forall(c in CRATES)(cratePosns[1,c] = crates[c]);
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%% no overlap of crates, walls and sokoban
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constraint forall(s in STEPS)(
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alldifferent(walls ++ [sokPosn[s]] ++ [cratePosns[s,c] | c in CRATES])
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);
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%% at the end all crates are in a position
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constraint forall(c in CRATES)(
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cratePosns[stime,c] in goals
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);
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% legal move at each step
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constraint forall(s in 1..stps-1)(
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sokPosn[s+1] - sokPosn[s] = move[s]
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);
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% crate pushing
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constraint forall(s in 1..stps-1, c in CRATES)(
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cratePosns[s+1,c] = cratePosns[s,c] + bool2int(sokPosn[s+1] == cratePosns[s,c]) * move[s]
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);
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solve minimize stime;
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output [show(sokPosn[s]) ++ " " | s in 1..fix(stime)] ++
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["\nstime = ", show(stime), "\n"];
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w = 5;
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n = 15;
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stps = 12;
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nw = 0;
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walls = [];
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nc = 2;
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crates = [7,9];
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goals = {6,15};
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pInit = 14;
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