Changeset 4373

Timestamp:

2016-06-06T19:49:20-07:00 (9 years ago)

Author:

Marek Rychlik

Message:

* empty log message *

File:

• branches/f4grobner/ring.lisp (modified) (2 diffs)

branches/f4grobner/ring.lisp

@@ -78 +78 @@
   (:documentation "Solves the diophantine system: X=C*X1, Y=C*X2,
 C=GCD(X,Y).  It returns three values: C, X1 and Y1. The result may be obtained by
-the Euclidean algorithm."))
+the Euclidean algorithm.")
+  (:method ((x t) (y t) &aux (c (universal-gcd x y)))
+    (values c (divide x c) (divide y c))))
 
 (defgeneric universal-equalp (self other)
@@ -99 +101 @@
 should be returned upon every call."))
 
+(defun add (summand &rest more-summands)
+  "Successively Adds to SUMMAND the elements of MORE-SUMMANDS. The first SUMMAND must not be destructively modified.
+Instead, a copy of factor should be made and returned as the value of
+this function."
+  (:method ((summand t) &rest more-summands)
+    (reduce #'add-to more-summands :initial-value (copy-instance summand))))
+
 (defgeneric multiply (factor &rest more-factors)
   (:documentation "Successively multiplies factor FACTOR by the remaining arguments