diff --git a/noise/fractal/base.ipp b/noise/fractal/base.ipp
index 557743ab..2a96a646 100644
--- a/noise/fractal/base.ipp
+++ b/noise/fractal/base.ipp
@@ -80,6 +80,15 @@ namespace util { namespace noise { namespace fractal {
     }
 
 
+    //-------------------------------------------------------------------------
+    template <typename T, typename B>
+    constexpr T
+    base<T,B>::frequency (void) const
+    {
+        return m_frequency;
+    }
+
+
     //-------------------------------------------------------------------------
     template <typename T, typename B>
     T