Changeset 3568

Timestamp:

09/04/03 00:18:18 (20 years ago)

Author:

piso

Message:

GCD

Location:

trunk/j/src/org/armedbear/lisp

Files:

• autoloads.lisp (modified) (2 diffs)
• numbers.lisp (modified) (2 diffs)

trunk/j/src/org/armedbear/lisp/autoloads.lisp

@@ -2 +2 @@
 ;;;
 ;;; Copyright (C) 2003 Peter Graves
-;;; $Id: autoloads.lisp,v 1.14 2003-09-02 17:50:32 piso Exp $
+;;; $Id: autoloads.lisp,v 1.15 2003-09-04 00:18:18 piso Exp $
 ;;;
 ;;; This program is free software; you can redistribute it and/or
@@ -74 +74 @@
 (autoload 'make-pathname)
 (autoload '(floor ceiling round rem mod ftruncate ffloor fceiling fround
-            rational rationalize isqrt)
+            rational rationalize gcd isqrt)
           "numbers.lisp")

trunk/j/src/org/armedbear/lisp/numbers.lisp

@@ -2 +2 @@
 ;;;
 ;;; Copyright (C) 2003 Peter Graves
-;;; $Id: numbers.lisp,v 1.9 2003-09-02 17:49:54 piso Exp $
+;;; $Id: numbers.lisp,v 1.10 2003-09-04 00:17:46 piso Exp $
 ;;;
 ;;; This program is free software; you can redistribute it and/or
@@ -164 +164 @@
                                rationalize)))
 
+
+
+(defun gcd (&rest numbers)
+  "Returns the greatest common divisor of the arguments, which must be
+   integers.  Gcd with no arguments is defined to be 0."
+  (unless (every #'integerp numbers)
+    (error 'type-error))
+  (cond ((null numbers) 0)
+  ((null (cdr numbers)) (abs (car numbers)))
+  (t
+   (do ((gcd (car numbers)
+       (gcd-2 gcd (car rest)))
+        (rest (cdr numbers) (cdr rest)))
+       ((null rest) gcd)))))