From: Richard Kreckel <Richard.Kreckel@uni-mainz.de>
Date: Thu, 7 Jun 2001 22:26:16 +0000 (+0000)
Subject: - matrix::pow(): omit last big multiplication if it's not needed.
X-Git-Tag: release_0-9-0~4
X-Git-Url: https://ginac.de/ginac.git/tutorial/ginac.git?a=commitdiff_plain;h=0086f1a95402fafa6333b987e3d38c72e5f402bc;p=ginac.git

- matrix::pow(): omit last big multiplication if it's not needed.
---

diff --git a/ginac/matrix.cpp b/ginac/matrix.cpp
index 9998a391..872b8e00 100644
--- a/ginac/matrix.cpp
+++ b/ginac/matrix.cpp
@@ -638,8 +638,8 @@ matrix matrix::pow(const ex & expn) const
 			for (unsigned r=0; r<row; ++r)
 				result(r,r) = _ex1();
 			numeric b(1);
-			// this loop computes the representation of k in base 2 and multiplies
-			// the factors whenever needed:
+			// this loop computes the representation of k in base 2 and
+			// multiplies the factors whenever needed:
 			while (b.compare(k)<=0) {
 				b *= numeric(2);
 				numeric r(mod(k,b));
@@ -647,7 +647,8 @@ matrix matrix::pow(const ex & expn) const
 					k -= r;
 					result = result.mul(prod);
 				}
-				prod = prod.mul(prod);
+				if (b.compare(k)<=0)
+					prod = prod.mul(prod);
 			}
 			return result;
 		}