Changeset 3713

Timestamp:

2015-09-06T07:38:35-07:00 (9 years ago)

Author:

Marek Rychlik

Message:

* empty log message *

File:

• branches/f4grobner/polynomial.lisp (modified) (1 diff)

branches/f4grobner/polynomial.lisp

@@ -481 +481 @@
 destructively modifies F and P."
   (polysaturation-extension f (list p)))
+
+(defgeneric universal-expt (x y)
+  (:method ((x number) (y integer)) (expt x y))
+  (:method ((x t) (y integer)) 
+    (declare (type fixnum y))
+    (cond
+      ((minusp y) (error "universal-expt: Negative exponent."))
+      ((universal-zerop x) (if (zerop y) 1))
+      (t
+       (do ((k 1 (ash k 1))
+            (q x (multiply q q))        ;keep squaring
+            (p 1 (if (not (zerop (logand k y))) (multiply p q) p)))
+           ((> k y) p)
+         (declare (fixnum k))))))
+  (:documentation "Raises X to power Y."))