1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% Sieve of eratosthenes to compute primes
%% thom fruehwirth 920218-20, 980311
%% christian holzbaur 980207 for Sicstus CHR
%%
%% ported to hProlog by Tom Schrijvers
%% Updated to current CHR and added how to extract the primes by
%% Jan Wielemaker.
:- module(primes,
[ candidate/1, % +Max
primes/2 % +Max, -ListOfPrimes
]).
:- use_module(library(chr)).
:- chr_constraint candidate/1.
:- chr_constraint prime/1.
candidate(1) <=> true.
candidate(N) <=> prime(N), N1 is N - 1, candidate(N1).
absorb @ prime(Y) \ prime(X) <=> 0 is X mod Y | true.
primes(Max, Primes) :-
findall(P,
( candidate(Max),
current_chr_constraint(prime(P))),
Primes).
|
