From 5d02171a6f959ed57203bead8c03f3a003adc4a8 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Tue, 20 Mar 2018 13:32:24 +1100
Subject: [PATCH] maths: add relatively_equal comparator

---
 maths.hpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/maths.hpp b/maths.hpp
index 0fb66b52..48a5edd7 100644
--- a/maths.hpp
+++ b/maths.hpp
@@ -11,7 +11,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
- * Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2010-2018 Danny Robson <danny@nerdcruft.net>
  */
 
 #ifndef __MATHS_HPP
@@ -81,6 +81,13 @@ namespace util {
     ///////////////////////////////////////////////////////////////////////////
     // Comparisons
     inline bool
+    relatively_equal (float a, float b, float percentage)
+    {
+        return std::abs (1 - b / a ) < percentage;
+    }
+
+    //-------------------------------------------------------------------------
+    inline bool
     almost_equal (float a, float b)
     {
         return ieee_single::almost_equal (a, b);