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yap-6.3/CHR/chr/examples/domain.pl

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% FINITE and INFINITE DOMAINS
% 910527 ECRC thom fruehwirth
% 910913 modified
% 920409 element/3 added
% 920616 more CHIP predicates added
% 930726 started porting to CHR release
% 931014 mult/3 added for CHIC user meeting
% 931201 ported to CHR release
% 931208 removed special case of integer domain
% 940304 element/3 constraint loop fixed
% 961017 Christian Holzbaur SICStus mods
% 980714 Thom Fruehwirth, some updates reagrding alread_in*
% just quick port from Eclipse CHR library version
% does not take advantage of Sicstus CHR library features!
% Simplifies domains together with inequalities and some more CHIP predicates:
% element/3, atmost/3, alldistinct/1, circuit/1 and mult/3
% It also includes paired (!) domains (see element constraint)
:- use_module( library(chr)).
:- use_module( library('chr/getval')).
:- use_module( library(lists), [member/2,last/2]).
:- use_module( library(ordsets),
[
list_to_ord_set/2,
ord_intersection/3
]).
handler domain.
option(already_in_store, on).
option(already_in_heads, off). % see pragma already_in_heads
option(check_guard_bindings, off).
% for domain constraints
operator(700,xfx,'::').
operator(600,xfx,'..').
operator(600,xfx,':'). % clash with module operator?
% for inequality constraints
operator(700,xfx,lt).
operator(700,xfx,le).
operator(700,xfx,gt).
operator(700,xfx,ge).
operator(700,xfx,ne).
% X::Dom - X must be element of the finite or infinite domain Dom
% Domains can be either numbers (including arithemtic expressions)
% or arbitrary ground terms (!), the domain is set with setval(domain,Kind),
% where Kind is either number or term. Default for Kind is term.
:- setval(domain,term). % set default
% INEQUALITIES ===============================================================
% inequalities over numbers (including arithmetic expressions) or terms
constraints lt/2,le/2,ne/2.
A gt B :- B lt A. % constraints gt/2,ge/2
A ge B :- B le A.
% some basic simplifications
A lt A <=> fail.
A le A <=> true.
A ne A <=> fail.
A lt B,B lt A <=> fail.
A le B,B le A <=> A=B.
A ne B \ B ne A <=> true.
% for number domain, allow arithmetic expressions in the arguments
A lt B <=> domain(number),ground(A),\+ number(A) | A1 is A, A1 lt B.
B lt A <=> domain(number),ground(A),\+ number(A) | A1 is A, B lt A1.
A le B <=> domain(number),ground(A),\+ number(A) | A1 is A, A1 le B.
B le A <=> domain(number),ground(A),\+ number(A) | A1 is A, B le A1.
A ne B <=> domain(number),ground(A),\+ number(A) | A1 is A, A1 ne B.
B ne A <=> domain(number),ground(A),\+ number(A) | A1 is A, B ne A1.
% use built-ins to solve the predicates if arguments are known
A lt B <=> ground(A),ground(B) | (domain(number) -> A < B ; A @< B).
A le B <=> ground(A),ground(B) | (domain(number) -> A =< B ; A @=< B).
A ne B <=> ground(A),ground(B) | (domain(number) -> A =\= B ; A \== B).
% FINITE and INFINITE DOMAINS ================================================
constraints (::)/2.
% enforce groundness of domain expression
X::Dom <=> nonground(Dom) |
raise_exception( instantiation_error(X::Dom,2)).
constraints labeling/0.
labeling, (X::[Y|L]) # Ph <=>
member(X,[Y|L]), labeling
pragma passive(Ph).
% binary search by splitting domain in halves
labeling, (X::Min:Max) # Ph <=> domain(number),Min+0.5<Max | % ensure termination
(integer(Min),integer(Max) -> % assume we have integer domain
Mid is (Min+Max)//2, Next is Mid+1
;
Mid is (Min+Max)/2, Next=Mid % splitted domains overlap at Mid for floats
),
(
X::Min:Mid
;
X::Next:Max
% ;
% Min+1>Max, % for floats only, to get X also bound
% X=Min % or X=Max etc.
),
labeling
pragma passive(Ph).
nonground(X) :- ground(X), !, fail.
nonground(_).
domain(Kind) :- getval(domain,Kind).
% CHIP list shorthand for domain variables
% list must be known (end in the empty list)
[X|L]::Dom <=> makedom([X|L],Dom).
makedom([],D) :- true.
makedom([X|L],D) :-
nonvar(L),
X::D,
makedom(L,D).
% Consecutive integer domain ---------------------------------------------
% X::Min..Max - X is an integer between the numbers Min and Max (included)
% constraint is mapped to enumeration domain constraint
X::Min..Max <=>
Min0 is Min,
(Min0=:=round(float(Min0)) -> Min1 is integer(Min0) ; Min1 is integer(Min0+1)),
Max1 is integer(Max),
interval(Min1,Max1,L),
X::L.
interval(M,N,[M|Ns]):-
M<N,
!,
M1 is M+1,
interval(M1,N,Ns).
interval(N,N,[N]).
% Enumeration domain -----------------------------------------------------
% X::Dom - X must be a ground term in the ascending sorted ground list Dom
X::[A|L] <=> list_to_ord_set([A|L],SL), SL\==[A|L] | X::SL.
% for number domain, allow arithmetic expressions in domain
X::[A|L] <=> domain(number), member(X,[A|L]), \+ number(X) |
eval_list([A|L],L1),list_to_ord_set(L1,L2), X::L2.
eval_list([],[]).
eval_list([X|L1],[Y|L2]):-
Y is X,
eval_list(L1,L2).
% special cases
X::[] <=> fail.
X::[Y] <=> X=Y.
X::[A|L] <=> ground(X) | (member(X,[A|L]) -> true).
% intersection of domains for the same variable
% without pragma already_in_heads, needs already_in_store
X::[A1|L1] \ X::[A2|L2] <=>
ord_intersection([A1|L1],[A2|L2],L),
L \== [A2|L2]
|
X::L.
% interaction with inequalities
X::[A|L] \ X ne Y <=> integer(Y), remove(Y,[A|L],L1) | X::L1.
X::[A|L] \ Y ne X <=> integer(Y), remove(Y,[A|L],L1) | X::L1.
X::[A|L], Y le X ==> ground(Y), remove_lower(Y,[A|L],L1) | X::L1.
X::[A|L], X le Y ==> ground(Y), remove_higher(Y,[A|L],L1) | X::L1.
X::[A|L], Y lt X ==> ground(Y), remove_lower(Y,[A|L],L1),remove(Y,L1,L2) | X::L2.
X::[A|L], X lt Y ==> ground(Y), remove_higher(Y,[A|L],L1),remove(Y,L1,L2) | X::L2.
% interaction with interval domain
X::[A|L], X::Min:Max ==> remove_lower(Min,[A|L],L1),remove_higher(Max,L1,L2) | X::L2.
% propagation of bounds
X le Y, Y::[A|L] ==> var(X) | last([A|L],Max), X le Max.
X le Y, X::[Min|_] ==> var(Y) | Min le Y.
X lt Y, Y::[A|L] ==> var(X) | last([A|L],Max), X lt Max.
X lt Y, X::[Min|_] ==> var(Y) | Min lt Y.
% Interval domain ---------------------------------------------------------
% X::Min:Max - X must be a ground term between Min and Max (included)
% for number domain, allow for arithmetic expressions ind omain
% for integer domains, X::Min..Max should be used
X::Min:Max <=> domain(number), \+ (number(Min),number(Max)) |
Min1 is Min, Max1 is Max, X::Min1:Max1.
% special cases
X::Min:Min <=> X=Min.
X::Min:Max <=> (domain(number) -> Min>Max ; Min@>Max) | fail.
X::Min:Max <=> ground(X) |
(domain(number) -> Min=<X,X=<Max ; Min@=<X,X@=<Max).
% intersection of domains for the same variable
% without pragma already_in_heads, needs already_in_store
X::Min1:Max1 \ X::Min2:Max2 <=> maximum(Min1,Min2,Min),
minimum(Max1,Max2,Max),
(Min \== Min2 ; Max \== Max2 ) |
X::Min:Max.
minimum(A,B,C):- (domain(number) -> A<B ; A@<B) -> A=C ; B=C.
maximum(A,B,C):- (domain(number) -> A<B ; A@<B) -> B=C ; A=C.
% interaction with inequalities
X::Min:Max \ X ne Y <=> ground(Y),
(domain(number) -> (Y<Min;Y>Max) ; (Y@<Min;Y@>Max)) | true.
X::Min:Max \ Y ne X <=> ground(Y),
(domain(number) -> (Y<Min;Y>Max) ; (Y@<Min;Y@>Max)) | true.
X::Min1:Max \ Min2 le X <=> ground(Min2) , maximum(Min1,Min2,Min) | X::Min:Max.
X::Min:Max1 \ X le Max2 <=> ground(Max2) , minimum(Max1,Max2,Max) | X::Min:Max.
X::Min1:Max \ Min2 lt X <=> ground(Min2) , maximum(Min1,Min2,Min) |
X::Min:Max, X ne Min.
X::Min:Max1 \ X lt Max2 <=> ground(Max2) , minimum(Max1,Max2,Max) |
X::Min:Max, X ne Max.
% propagation of bounds
X le Y, Y::Min:Max ==> var(X) | X le Max.
X le Y, X::Min:Max ==> var(Y) | Min le Y.
X lt Y, Y::Min:Max ==> var(X) | X lt Max.
X lt Y, X::Min:Max ==> var(Y) | Min lt Y.
% MULT/3 EXAMPLE EXTENSION ==================================================
% mult(X,Y,C) - integer X multiplied by integer Y gives the integer constant C.
constraints mult/3.
mult(X,Y,C) <=> ground(X) | (X=:=0 -> C=:=0 ; 0=:=C mod X, Y is C//X).
mult(Y,X,C) <=> ground(X) | (X=:=0 -> C=:=0 ; 0=:=C mod X, Y is C//X).
mult(X,Y,C), X::MinX:MaxX ==>
%(Dom=MinX:MaxX -> true ; Dom=[MinX|L],last(L,MaxX)),
MinY is (C-1)//MaxX+1,
MaxY is C//MinX,
Y::MinY:MaxY.
mult(Y,X,C), X::MinX:MaxX ==>
%(Dom=MinX:MaxX -> true ; Dom=[MinX|L],last(L,MaxX)),
MinY is (C-1)//MaxX+1,
MaxY is C//MinX,
Y::MinY:MaxY.
/*
:- mult(X,Y,156),[X,Y]::2:156,X le Y.
X = X_g307
Y = Y_g331
Constraints:
(1) mult(X_g307, Y_g331, 156)
(7) Y_g331 :: 2 : 78
(8) X_g307 :: 2 : 78
(10) X_g307 le Y_g331
yes.
:- mult(X,Y,156),[X,Y]::2:156,X le Y,labeling.
X = 12
Y = 13 More? (;)
X = 6
Y = 26 More? (;)
X = 4
Y = 39 More? (;)
X = 2
Y = 78 More? (;)
X = 3
Y = 52 More? (;)
no (more) solution.
*/
% CHIP ELEMENT/3 ============================================================
% translated to "pair domains", a very powerful extension of usual domains
% this version does not work with arithmetic expressions!
element(I,VL,V):- length(VL,N),interval(1,N,IL),gen_pair(IL,VL,BL), I-V::BL.
gen_pair([],[],[]).
gen_pair([A|L1],[B|L2],[A-B|L3]):-
gen_pair(L1,L2,L3).
% special cases
I-I::L <=> setof(X,member(X-X,L),L1), I::L1.
I-V::L <=> ground(I) | setof(X,member(I-X,L),L1), V::L1.
I-V::L <=> ground(V) | setof(X,member(X-V,L),L1), I::L1.
% intersections
X::[A|L1], X-Y::L2 <=> intersect(I::[A|L1],I-V::L2,I-V::L3),
length(L2,N2),length(L3,N3),N2>N3 | X-Y::L3.
Y::[A|L1], X-Y::L2 <=> intersect(V::[A|L1],I-V::L2,I-V::L3),
length(L2,N2),length(L3,N3),N2>N3 | X-Y::L3.
X-Y::L1, Y-X::L2 <=> intersect(I-V::L1,V-I::L2,I-V::L3) | X-Y::L3.
X-Y::L1, X-Y::L2 <=> intersect(I-V::L1,I-V::L2,I-V::L3) | X-Y::L3 pragma already_in_heads.
intersect(A::L1,B::L2,C::L3):- setof(C,A^B^(member(A,L1),member(B,L2)),L3).
% inequalties with two common variables
Y lt X, X-Y::L <=> A=R-S,setof(A,(member(A,L),R@< S),L1) | X-Y::L1.
X lt Y, X-Y::L <=> A=R-S,setof(A,(member(A,L),S@< R),L1) | X-Y::L1.
Y le X, X-Y::L <=> A=R-S,setof(A,(member(A,L),R@=<S),L1) | X-Y::L1.
X le Y, X-Y::L <=> A=R-S,setof(A,(member(A,L),S@=<R),L1) | X-Y::L1.
Y ne X, X-Y::L <=> A=R-S,setof(A,(member(A,L),R\==S),L1) | X-Y::L1.
X ne Y, X-Y::L <=> A=R-S,setof(A,(member(A,L),S\==R),L1) | X-Y::L1.
% propagation between paired domains (path-consistency)
% X-Y::L1, Y-Z::L2 ==> intersect(A-B::L1,B-C::L2,A-C::L), X-Z::L.
% X-Y::L1, Z-Y::L2 ==> intersect(A-B::L1,C-B::L2,A-C::L), X-Z::L.
% X-Y::L1, X-Z::L2 ==> intersect(I-V::L1,I-W::L2,V-W::L), Y-Z::L.
% propagation to usual unary domains
X-Y::L ==> A=R-S,setof(R,A^member(A,L),L1), X::L1,
setof(S,A^member(A,L),L2), Y::L2.
% ATMOST/3 ===================================================================
atmost(N,List,V):-length(List,K),atmost(N,List,V,K).
constraints atmost/4.
atmost(N,List,V,K) <=> K=<N | true.
atmost(0,List,V,K) <=> (ground(V);ground(List)) | outof(V,List).
atmost(N,List,V,K) <=> K>N,ground(V),delete_ground(X,List,L1) |
(X==V -> N1 is N-1 ; N1=N),K1 is K-1, atmost(N1,L1,V,K1).
delete_ground(X,List,L1):- delete(X,List,L1),ground(X),!.
delete( X, [X|Xs], Xs).
delete( Y, [X|Xs], [X|Xt]) :-
delete( Y, Xs, Xt).
% ALLDISTINCT/1 ===============================================================
% uses ne/2 constraint
constraints alldistinct/1.
alldistinct([]) <=> true.
alldistinct([X]) <=> true.
alldistinct([X,Y]) <=> X ne Y.
alldistinct([A|L]) <=> delete_ground(X,[A|L],L1) | outof(X,L1),alldistinct(L1).
alldistinct([]).
alldistinct([X|L]):-
outof(X,L),
alldistinct(L).
outof(X,[]).
outof(X,[Y|L]):-
X ne Y,
outof(X,L).
constraints alldistinct1/2.
alldistinct1(R,[]) <=> true.
alldistinct1(R,[X]), X::[A|L] <=> ground(R) |
remove_list(R,[A|L],T), X::T.
alldistinct1(R,[X]) <=> (ground(R);ground(X)) | outof(X,R).
alldistinct1(R,[A|L]) <=> ground(R),delete_ground(X,[A|L],L1) |
(member(X,R) -> fail ; alldistinct1([X|R],L1)).
% CIRCUIT/1 =================================================================
% constraints circuit1/1, circuit/1.
% uses list domains and ne/2
% lazy version
circuit1(L):-length(L,N),N>1,circuit1(N,L).
circuit1(2,[2,1]).
circuit1(N,L):- N>2,
interval(1,N,D),
T=..[f|L],
domains1(1,D,L),
alldistinct1([],L),
no_subtours(N,1,T,[]).
domains1(N,D,[]).
domains1(N,D,[X|L]):-
remove(N,D,DX),
X::DX,
N1 is N+1,
domains1(N1,D,L).
no_subtours(0,N,L,R):- !.
no_subtours(K,N,L,R):-
outof(N,R),
(var(N) -> freeze(N,no_subtours1(K,N,L,R)) ; no_subtours1(K,N,L,R)).
% no_subtours(K,N,T,R) \ no_subtours(K1,N,T,_) <=> K<K1 | true.
no_subtours1(K,N,L,R):-
K>0,K1 is K-1,arg(N,L,A),no_subtours(K1,A,L,[N|R]).
% eager version
circuit(L):- length(L,N),N>1,circuit(N,L).
circuit(2,[2,1]).
%circuit(3,[2,3,1]).
%circuit(3,[3,1,2]).
circuit(N,L):- N>2,
interval(1,N,D),
T=..[f|L],
N1 is N-1,
domains(1,D,L,T,N1),
alldistinct(L).
domains(N,D,[],T,K).
domains(N,D,[X|L],T,K):-
remove(N,D,DX),
X::DX,
N1 is N+1,
no_subtours(K,N,T,[]), % unfolded
%no_subtours1(K,X,T,[N]),
domains(N1,D,L,T,K).
% remove*/3 auxiliary predicates =============================================
remove(A,B,C):-
delete(A,B,C) -> true ; B=C.
remove_list(_,[],T):- !, T=[].
remove_list([],S,T):- S=T.
remove_list([X|R],[Y|S],T):- remove(X,[Y|S],S1),remove_list(R,S1,T).
remove_lower(_,[],L1):- !, L1=[].
remove_lower(Min,[X|L],L1):-
X@<Min,
!,
remove_lower(Min,L,L1).
remove_lower(Min,[X|L],[X|L1]):-
remove_lower(Min,L,L1).
remove_higher(_,[],L1):- !, L1=[].
remove_higher(Max,[X|L],L1):-
X@>Max,
!,
remove_higher(Max,L,L1).
remove_higher(Max,[X|L],[X|L1]):-
remove_higher(Max,L,L1).
% end of handler domain.chr =================================================
% ===========================================================================