Rename to clnl, add documentation

[clnl] / src / main / random.lisp

diff --git a/src/main/random.lisp b/src/main/random.lisp
index 7fca5a183d4360398f9ac129b2275067b5891da7..6f500a979558a57fdd519d4323878ab43a5e8052 100644 (file)
--- a/src/main/random.lisp
+++ b/src/main/random.lisp
@@ -1,8 +1,4 @@
-(defpackage #:cl-nl.random
- (:use :common-lisp)
- (:export :set-seed :next-int :next-double))
-
-(in-package #:cl-nl.random)
+(in-package #:clnl-random)
 
 ; This is a wrapper around the very nice mersenne twister mt19937 to match
 ; NetLogo's implementation that tries to match how java.util.Random works
@@ -11,7 +7,10 @@
  (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
@@ -22,3 +21,15 @@
    (+ (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))))