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Download(c) 2005-2025 XLOG Technologies AG
/**
* Warranty & Liability
* To the extent permitted by applicable law and unless explicitly
* otherwise agreed upon, XLOG Technologies AG makes no warranties
* regarding the provided information. XLOG Technologies AG assumes
* no liability that any problems might be solved with the information
* provided by XLOG Technologies AG.
*
* Rights & License
* All industrial property rights regarding the information - copyright
* and patent rights in particular - are the sole property of XLOG
* Technologies AG. If the company was not the originator of some
* excerpts, XLOG Technologies AG has at least obtained the right to
* reproduce, change and translate the information.
*
* Reproduction is restricted to the whole unaltered document. Reproduction
* of the information is only allowed for non-commercial uses. Selling,
* giving away or letting of the execution of the library is prohibited.
* The library can be distributed as part of your applications and libraries
* for execution provided this comment remains unchanged.
*
* Restrictions
* Only to be distributed with programs that add significant and primary
* functionality to the library. Not to be distributed with additional
* software intended to replace any components of the library.
*
* Trademarks
* Jekejeke is a registered trademark of XLOG Technologies AG.
*/
/**
* random(M, N):
* The predicate succeeds in N with a uniform random arbitrary
* large integer value in the interval [0..M).
*/
% random(+Integer, -Integer)
random(M, _) :- M =< 0,
throw(error(evaluation_error(undefined))).
random(M, N) :-
L is msb(M)+1,
repeat,
sys_random_bits(L, H),
H < M, !,
H = N.
% sys_random_bits(+Integer, -Integer)
sys_random_bits(L, B) :-
divmod(L, 32, X, Y),
random(W), D is floor(W*(1<<Y)),
sys_random_bits(X, D, B).
% sys_random_bits(+Integer, +Integer, -Integer)
sys_random_bits(0, A, A) :- !.
sys_random_bits(X, A, B) :-
random(W), D is floor(W*(1<<32)),
H is (A<<32)+D,
Z is X-1,
sys_random_bits(Z, H, B).
% testbit(+Integer, +Integer)
testbit(X, Y) :-
X /\ (1 << Y) =\= 0.
% divmod(+Integer, +Integer, -Integer, -Integer)
divmod(X, Y, D, M) :-
D is X div Y,
M is X - D*Y.