diff --git a/point.cpp b/point.cpp
index 66cf1cb4..d35c75e7 100644
--- a/point.cpp
+++ b/point.cpp
@@ -48,8 +48,8 @@ util::furthest (util::view<const util::point<S,T>*> src)
 {
     CHECK_GE (src.size (), 2u);
 
-    auto a = 0;
-    auto b = 1;
+    size_t a = 0;
+    size_t b = 1;
     auto d = distance2 (src[a],src[b]);
 
     for (size_t i = 0; i < src.size (); ++i) {