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Merge pull request #1648 from aarroyoc/docs-random

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Compatible Doclog docs for library(random)
This commit is contained in:
Mark Thom
2022-12-05 06:05:02 +01:00
committed by GitHub
parent a19f7a0b9f b2a0d0c1c7
commit 73780ebf63
1 changed files with 25 additions and 7 deletions
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32
src/lib/random.pl
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@@ -1,24 +1,38 @@
:- module(random, [maybe/0, random/1, random_integer/3, set_random/1]).
/**
This library provides probabilistic predicates and random number generators.
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
To retain desirable declarative properties, predicates that internally
use random numbers should be equipped with an argument that specifies
the random seed. This makes everything completely reproducible.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
To retain desirable declarative properties, predicates that internally
use random numbers should be equipped with an argument that specifies
the random seed. This makes everything completely reproducible.
*/
:- module(random, [maybe/0, random/1, random_integer/3, set_random/1]).
:- use_module(library(error)).
% succeeds with probability 0.5.
%% maybe.
%
% Succeeds with probability 0.5.
maybe :- '$maybe'.
% The higher the precision, the slower it gets.
random_number_precision(64).
%% random(-R).
%
% Generates a random floating number between 0 (inclusive) and 1 (exclusive).
random(R) :-
var(R),
random_number_precision(N),
rnd(N, R).
%% random_integer(+Lower, +Upper, -R).
%
% Generates a random integer number between Lower (inclusive) and Upper (exclusive).
%
% Throws instantiation\_error if Lower or Upper are variables.
%
% Throws type\_error if Lower or Upper aren't integers.
random_integer(Lower, Upper, R) :-
var(R),
( (var(Lower) ; var(Upper)) ->
@@ -46,6 +60,10 @@ rnd_(N, R0, R) :-
R1 is R0 + 1.0 / 2.0 ^ N,
rnd_(N1, R1, R).
%% set_random(+Seed).
%
% Sets a seed that will be used for subsequent random generations in this library.
% It's necessary to set a seed to provide reproducible executions using this library.
set_random(Seed) :-
( nonvar(Seed) ->
( Seed = seed(S) ->