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yap-6.3/LGPL/chr/Benchmarks/fib.chr
vsc a247b1b8ec include CHR benchmarks
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1958 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
2007-10-16 23:18:30 +00:00

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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% 991202 Slim Abdennadher, LMU
%%
%% ported to hProlog by Tom Schrijvers
:- module(fib,[main/0,main/1]).
:- use_module(library(chr)).
:- chr_constraint fib/2.
%% fib(N,M) is true if M is the Nth Fibonacci number.
%% Top-down Evaluation with Tabulation
fib(N,M1), fib(N,M2) <=> M1 = M2, fib(N,M1).
fib(0,M) ==> M = 1.
fib(1,M) ==> M = 1.
fib(N,M) ==> N > 1 | N1 is N-1, fib(N1,M1), N2 is N-2, fib(N2,M2), M is M1 + M2.
main :-
main(22).
main(N):-
cputime(X),
fib(N,_),
cputime( Now),
Time is Now-X,
write(bench(fib ,N,Time, 0, hprolog)),write('.'), nl.