From dc34369e236a71c573db4b6a993488b594820aa4 Mon Sep 17 00:00:00 2001
From: Toki Migimatsu <toki.migimatsu@gmail.com>
Date: Mon, 22 Jul 2019 15:39:56 -0700
Subject: [PATCH] Fix undefined difference operation

---
 include/fl/distribution/gaussian.hpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/fl/distribution/gaussian.hpp b/include/fl/distribution/gaussian.hpp
index d1503ea..df398c1 100644
--- a/include/fl/distribution/gaussian.hpp
+++ b/include/fl/distribution/gaussian.hpp
@@ -461,10 +461,9 @@ class Gaussian
 
         if(has_full_rank())
         {
+            const Variate dx = vector - mean();
             return log_normalizer() - 0.5
-                    * (vector - mean()).transpose()
-                    * precision()
-                    * (vector - mean());
+                    * (dx.transpose() * precision() * dx)(0);
         }
 
         return -std::numeric_limits<Real>::infinity();