From fa3f23105ddcf07c5900de47f19af43d1db1b597 Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@robocracy.org>
Date: Mon, 20 Feb 2017 00:05:27 -0800
Subject: Import Upstream version 2c3

---
 randinex.scm | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

(limited to 'randinex.scm')

diff --git a/randinex.scm b/randinex.scm
index 1c2b702..e6dc48b 100644
--- a/randinex.scm
+++ b/randinex.scm
@@ -22,28 +22,26 @@
 
 ;;; Fixed sphere and normal functions from: Harald Hanche-Olsen
 
-(define random:float-radix
-  (+ 1 (exact->inexact random:MASK)))
-
-;;; This determines how many chunks will be neccessary to completely
-;;; fill up an inexact real.
-(define (random:size-float l x)
-  (cond ((= 1.0 (+ 1 x)) l)
-	((= 4 l) l)
-	(else (random:size-float (+ l 1) (/ x random:float-radix)))))
-(define random:chunks/float (random:size-float 0 1.0))
-
-(define (random:uniform-chunk n state)
-  (if (= 1 n)
-      (/ (exact->inexact (random:chunk state))
-	 random:float-radix)
-      (/ (+ (random:uniform-chunk (- n 1) state)
-	    (exact->inexact (random:chunk state)))
-	 random:float-radix)))
-
 ;;; Generate an inexact real between 0 and 1.
-(define (random:uniform state)
-  (random:uniform-chunk random:chunks/float state))
+(define random:uniform
+  (letrec ((random:chunks/float		; how many chunks fill an inexact?
+	    (letrec ((random:size-float
+		      (lambda (l x)
+			(cond ((= 1.0 (+ 1 x)) l)
+			      ((= 4 l) l)
+			      (else (random:size-float (+ l 1) (/ x 256.0)))))))
+	      (random:size-float 0 1.0)))
+
+	   (random:uniform-chunk
+	    (lambda (n state)
+	      (if (= 1 n)
+		  (/ (exact->inexact (random:chunk state))
+		     256.0)
+		  (/ (+ (random:uniform-chunk (- n 1) state)
+			(exact->inexact (random:chunk state)))
+		     256.0)))))
+    (lambda (state)
+      (random:uniform-chunk random:chunks/float state))))
 
 ;;; If x and y are independent standard normal variables, then with
 ;;; x=r*cos(t), y=r*sin(t), we find that t is uniformly distributed
@@ -81,7 +79,7 @@
 
 ;;; For the uniform distribution on the solid sphere, note that in
 ;;; this distribution the length r of the vector has cumulative
-;;; distribution r^n; i.e., u=r^n is uniform [0,1], so r kan be
+;;; distribution r^n; i.e., u=r^n is uniform [0,1], so r can be
 ;;; generated as r=u^(1/n).
 
 (define (random:solid-sphere! vect . args)
@@ -95,5 +93,3 @@
 (define (random:exp . args)
   (let ((state (if (null? args) *random-state* (car args))))
     (- (log (random:uniform state)))))
-
-(require 'random)
-- 
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