+/// Return true if smaller, good for putting that into a std::map
+template<typename T>
+inline
+bool
+operator<(const SGVec4<T>& v1, const SGVec4<T>& v2)
+{
+ if (v1(0) < v2(0)) return true;
+ else if (v2(0) < v1(0)) return false;
+ else if (v1(1) < v2(1)) return true;
+ else if (v2(1) < v1(1)) return false;
+ else if (v1(2) < v2(2)) return true;
+ else if (v2(2) < v1(2)) return false;
+ else return (v1(3) < v2(3));
+}
+
+template<typename T>
+inline
+bool
+operator<=(const SGVec4<T>& v1, const SGVec4<T>& v2)
+{
+ if (v1(0) < v2(0)) return true;
+ else if (v2(0) < v1(0)) return false;
+ else if (v1(1) < v2(1)) return true;
+ else if (v2(1) < v1(1)) return false;
+ else if (v1(2) < v2(2)) return true;
+ else if (v2(2) < v1(2)) return false;
+ else return (v1(3) <= v2(3));
+}
+
+template<typename T>
+inline
+bool
+operator>(const SGVec4<T>& v1, const SGVec4<T>& v2)
+{ return operator<(v2, v1); }
+
+template<typename T>
+inline
+bool
+operator>=(const SGVec4<T>& v1, const SGVec4<T>& v2)
+{ return operator<=(v2, v1); }
+