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%%
%% Sieve of eratosthenes to compute primes
%% thom fruehwirth 920218-20, 980311
%% christian holzbaur 980207 for Sicstus CHR
%%

:- module(primes,[main/0,main/1]).

:- use_module(library(chr)).

handler primes.

constraints candidate/1.
constraints prime/1.

candidate(1) <=> true.
candidate(N) <=> prime(N), N1 is N - 1, candidate(N1).

absorb @ prime(Y) \ prime(X) <=> 0 =:= X mod Y | true.

main :-
	main(2500).

main(N):-
	statistics(runtime,[X|_]),
	candidate(N),
	statistics(runtime,[ Now|_]),
	Time is Now-X,
	write(bench(primes,N,Time,0,sicstus)), write('.'),  nl.