Test Queens3

Jan Burse, erstellt 01. Sep 2016
/**
* CLP(FD) Prolog code for eight queens puzzle.
* With balance/3 and setup_balance/3 test cases.
* Jekejeke Prolog version.
*
* Originally conceived in by Max Bezzel for the 8x8 checker board.
* Used by Edsger Dijkstra to illustrate the
* Depth-first backtracking search algorithm.
*
* Warranty & Liability
* To the extent permitted by applicable law and unless explicitly
* otherwise agreed upon, XLOG Technologies GmbH makes no warranties
* regarding the provided information. XLOG Technologies GmbH assumes
* no liability that any problems might be solved with the information
* provided by XLOG Technologies GmbH.
*
* Rights & License
* All industrial property rights regarding the information - copyright
* and patent rights in particular - are the sole property of XLOG
* Technologies GmbH. If the company was not the originator of some
* excerpts, XLOG Technologies GmbH has at least obtained the right to
* reproduce, change and translate the information.
*
* Reproduction is restricted to the whole unaltered document. Reproduction
* of the information is only allowed for non-commercial uses. Selling,
* giving away or letting of the execution of the library is prohibited.
* The library can be distributed as part of your applications and libraries
* for execution provided this comment remains unchanged.
*
* Trademarks
* Jekejeke is a registered trademark of XLOG Technologies GmbH.
*/
:- use_module(library(runtime/distributed)).
:- use_module(library(advanced/arith)).
:- use_module(library(finite/clpfd)).
:- use_module(library(basic/lists)).
/*****************************************************************/
/* Normal Test Cases */
/*****************************************************************/
cross(8, X, Y),
modellabel(8, [X,Y|_]).
balance(( cross(8, X, Y),
modellabel(8, [X,Y|_])), 2).
balance(( cross(8, X, Y),
modellabel(8, [X,Y|_])), 4).
balance(( cross(8, X, Y),
modellabel(8, [X,Y|_])), 8).
model(8, [X,Y|Z]),
cross(8, X, Y),
label([X,Y|Z]).
setup_balance(( model(8, [X,Y|Z]),
cross(8, X, Y),
label([X,Y|Z])), 2).
setup_balance(( model(8, [X,Y|Z]),
cross(8, X, Y),
label([X,Y|Z])), 4).
setup_balance(( model(8, [X,Y|Z]),
cross(8, X, Y),
label([X,Y|Z])), 8).
/*****************************************************************/
/* Reduced Test Cases */
/*****************************************************************/
cross(6, X, Y),
modellabel(6, [X,Y|_]).
balance(( cross(6, X, Y),
modellabel(6, [X,Y|_])), 2).
balance(( cross(6, X, Y),
modellabel(6, [X,Y|_])), 4).
balance(( cross(6, X, Y),
modellabel(6, [X,Y|_])), 8).
model(6, [X,Y|Z]),
cross(6, X, Y),
label([X,Y|Z]).
setup_balance(( model(6, [X,Y|Z]),
cross(6, X, Y),
label([X,Y|Z])), 2).
setup_balance(( model(6, [X,Y|Z]),
cross(6, X, Y),
label([X,Y|Z])), 4).
setup_balance(( model(6, [X,Y|Z]),
cross(6, X, Y),
label([X,Y|Z])), 8).
/*****************************************************************/
/* The Queens Problem */
/*****************************************************************/
% modellabel(+Integer, -List)
model(N, X),
label(X).
% model(+Integer, -List)
model(N, X) :-
length(X, N),
X ins 1..N,
% cross(+Integer, -Integer, -Integer)
cross(N, X, Y) :-
between(1, N, X),
between(1, N, Y).
% noattack_from(+List, +Variable, +Integer)
noattack_from([], _, _).
noattack_from([Y|Z], X, N) :-
X+N #\= Y,
Y+N #\= X,
M is N+1,
noattack_from(Z, X, M).
% noattack_list(+List)
noattack_from(Y, X, 1),

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