bpigeon.pl

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/*-------------------------------------------------------------------------*/
/* Benchmark (Boolean)                                                     */
/*                                                                         */
/* Name           : bpigeon.pl                                             */
/* Title          : pigeon-hole problem                                    */
/* Originated from:                                                        */
/* Adapted by     : Daniel Diaz for CLP(FD)                                */
/* Date           : January 1993                                           */
/*                                                                         */
/* Put N pigeons in M pigeon-holes. Solution iff N<=M.                     */
/* The solution is a list [ [Pig11,...,Pig1m], ... ,[Pign1,...,Pignm] ]    */
/* where Pigij = 1 if the pigeon i is in the pigeon-hole j                 */
/*                                                                         */
/* Solution:                                                               */
/* N=2 M=3 [[0,0,1],[0,1,0]]                                               */
/*         [[0,0,1],[1,0,0]]                                               */
/*         [[0,1,0],[0,0,1]]                                               */
/*         [[0,1,0],[1,0,0]]                                               */
/*         [[1,0,0],[0,0,1]]                                               */
/*         [[1,0,0],[0,1,0]]                                               */
/*-------------------------------------------------------------------------*/
:-write('you need array.pl (www.probp.com/libraryplus/array.pl) to run this program.'),nl.

top:-
    N=4,
    N=5,
    (bpigeon(N,M,A),
     write(A),nl,
     fail
     ;
     write('No more solutions'), nl).
    
go:-	
    statistics(runtime,_),
    top,
    statistics(runtime,[_,Y]),
    write('time : '), write(Y), nl.


bpigeon(N,M,A):-
    create_array(N,M,A),
    for_each_line(A,fd_only_one),
    for_each_column(A,fd_at_most_one),
    !,
    array_labeling(A).

:-load(array).