From: Steinar H. Gunderson <sesse@debian.org>
Date: Sun, 2 Dec 2007 14:44:07 +0000 (+0100)
Subject: Optimize the sech²(x) function a bit.
X-Git-Url: https://git.sesse.net/?p=foosball;a=commitdiff_plain;h=f7903bdddb48a163a6902e832247d0f97a8ad664

Optimize the sech²(x) function a bit.
---

diff --git a/foosrank.cpp b/foosrank.cpp
index 67aee58..d295c21 100644
--- a/foosrank.cpp
+++ b/foosrank.cpp
@@ -32,8 +32,8 @@ static double fac(int x);
 // sech²(x)
 static double sech2(double x)
 {
-	double c = cosh(x);
-	return 1.0 / (c*c);
+	double e = exp(2.0 * x);
+	return 4.0 * e / ((e+1.0) * (e+1.0));
 }
 #endif