This repository has been archived on 2023-08-20. You can view files and clone it, but cannot push or open issues or pull requests.
yap-6.3/packages/chr/Examples/leq.chr

35 lines
771 B
Plaintext
Raw Normal View History

2015-10-13 08:17:51 +01:00
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% simple constraint solver for inequalities between variables
%% thom fruehwirth ECRC 950519, LMU 980207, 980311
%%
%% ported to hProlog by Tom Schrijvers
:- module(leq,[]).
:- use_module(library(chr)).
:- constraints leq/2.
reflexivity @ leq(X,X) <=> true.
antisymmetry @ leq(X,Y), leq(Y,X) <=> X = Y.
idempotence @ leq(X,Y) \ leq(X,Y) <=> true.
transitivity @ leq(X,Y), leq(Y,Z) ==> leq(X,Z).
t(N):-
cputime(X),
length(L,N),
genleq(L,Last),
L=[First|_],
leq(Last,First),
cputime( Now),
Time is Now-X,
write(N-Time), nl.
genleq([Last],Last) :- ! .
genleq([X,Y|Xs],Last):-
leq(X,Y),
genleq([Y|Xs],Last).
cputime( Ts) :-
statistics( runtime, [Tm,_]),
Ts is Tm/1000.