-(defpackage #:cl-nl.random
- (:use :common-lisp)
- (:export :set-seed :next-int :next-double))
-
(in-package #:cl-nl.random)
; This is a wrapper around the very nice mersenne twister mt19937 to match
(setf mt19937:*random-state* (mt19937::make-random-object :state (mt19937:init-random-state n))))
(defun next-int (n)
- (rem (ash (mt19937:random-chunk mt19937:*random-state*) -1) n))
+ (if
+ (= n (logand n (- n) ))
+ (ash (* n (ash (mt19937:random-chunk mt19937:*random-state*) -1) ) -31)
+ (rem (ash (mt19937:random-chunk mt19937:*random-state*) -1) n)))
(defun next-double (&optional (n 1d0))
(let
(+ (ash (ash y -6) 27) (ash z -5))
(coerce (ash 1 53) 'double-float))
n)))
+
+; Oh, export world, you WILL be mine
+(defun export ()
+ (let
+ ((state
+ (map
+ 'list
+ (lambda (x) (if (logbitp (1- 32) x) (dpb x (byte 32 0) -1) x))
+ (mt19937::random-state-state mt19937:*random-state*))))
+ (format nil "0 ~A ~A ~A 0.0 false ~{~A~^ ~}"
+ (first state) (second state) (third state)
+ (nthcdr 3 state))))