diff options
Diffstat (limited to 'src/clojure/contrib/math.clj')
| -rw-r--r-- | src/clojure/contrib/math.clj | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/clojure/contrib/math.clj b/src/clojure/contrib/math.clj index 0f4ff622..f7176a59 100644 --- a/src/clojure/contrib/math.clj +++ b/src/clojure/contrib/math.clj @@ -10,6 +10,7 @@ ;; otherwise returns a double.
;; abs - (abs n) is the absolute value of n
;; gcd - (gcd m n) returns the greatest common divisor of m and n
+;; lcm - (lcm m n) returns the least common multiple of m and n
;; The behavior of the next three functions on doubles is consistent
;; with the behavior of the corresponding functions
@@ -121,6 +122,15 @@ round always returns an integer. Rounds up for values exactly in between two in (if (zero? b) a,
(recur b (mod a b))))))
+(defn lcm
+ "(lcm a b) returns the least common multiple of a and b"
+ [a b]
+ (when (or (not (integer? a)) (not (integer? b)))
+ (throw (IllegalArgumentException. "lcm requires two integers")))
+ (cond (zero? a) 0
+ (zero? b) 0
+ :else (abs (* b (quot a (gcd a b))))))
+
; Length of integer in binary, used as helper function for sqrt.
(defmulti #^{:private true} integer-length class)
(defmethod integer-length java.lang.Integer [n]
|