From 68adb324726d8b7c6c3304a7949aa06dfd995491 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Thu, 3 May 2012 15:56:56 +1000
Subject: [PATCH] Add is_zero for vector magnitude

---
 vector.cpp | 8 ++++++++
 vector.hpp | 2 ++
 2 files changed, 10 insertions(+)

diff --git a/vector.cpp b/vector.cpp
index db391c0c..d79e273c 100644
--- a/vector.cpp
+++ b/vector.cpp
@@ -184,6 +184,14 @@ vector::cartesian_to_spherical (const vector &c) {
 }
 
 
+bool
+vector::is_zero (void) const {
+    return almost_equal (x, 0.0) &&
+           almost_equal (y, 0.0) &&
+           almost_equal (z, 0.0);
+}
+
+
 void
 vector::sanity (void) const {
     check_soft (!std::isnan (x));
diff --git a/vector.hpp b/vector.hpp
index 26cbdd69..7e53550b 100644
--- a/vector.hpp
+++ b/vector.hpp
@@ -56,6 +56,8 @@ namespace util {
         static vector spherical_to_cartesian (const vector &);
         static vector cartesian_to_spherical (const vector &);
 
+        bool is_zero (void) const;
+
         void sanity (void) const;
     };