From 19f7ba742a529fae933b494f317a648205e2a28d Mon Sep 17 00:00:00 2001
From: Jonathan J Lawlor <jonathan.lawlor@gmail.com>
Date: Sun, 19 Oct 2014 21:59:35 -0400
Subject: [PATCH] simplify implementation of cross entropy

Changed the implementation to match the simpler flow of Entropy.  This
will also result in fewer operations.
---
 stat.go | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/stat.go b/stat.go
index d16d5d4c..f5c12045 100644
--- a/stat.go
+++ b/stat.go
@@ -176,11 +176,9 @@ func CrossEntropy(p, q []float64) float64 {
 	}
 	var ce float64
 	for i, v := range p {
-		w := q[i]
-		if v == 0 && w == 0 {
-			continue
+		if v != 0 {
+			ce -= v * math.Log(q[i])
 		}
-		ce -= v * math.Log(w)
 	}
 	return ce
 }