diff --git a/cpp/Makefile.am b/cpp/Makefile.am
index d69115d15..9f6e80a1a 100644
--- a/cpp/Makefile.am
+++ b/cpp/Makefile.am
@@ -49,7 +49,7 @@ testMatrix_LDADD   = libgtsam.la
 
 # GTSAM basics
 # The header files will be installed in ~/include/gtsam
-headers = gtsam.h Value.h Testable.h Factor.h Conditional.h 
+headers = gtsam.h Value.h Testable.h Factor.h Conditional.h Ordering.h Ordering-inl.h
 sources += Ordering.cpp  
 example = smallExample.cpp 
 
diff --git a/cpp/Ordering-inl.h b/cpp/Ordering-inl.h
new file mode 100644
index 000000000..e8c89a19d
--- /dev/null
+++ b/cpp/Ordering-inl.h
@@ -0,0 +1,48 @@
+/*
+ * Ordering-inl.h
+ *
+ *   Created on: Jan 14, 2010
+ *       Author: nikai
+ *  Description: the inline file for Ordering
+ */
+
+#pragma once
+
+#include "graph-inl.h"
+#include "Ordering.h"
+
+using namespace std;
+
+namespace gtsam {
+
+/* ************************************************************************* */
+template <class Key>
+class ordering_key_visitor : public boost::default_bfs_visitor {
+public:
+	ordering_key_visitor(std::list<Key>& ordering_in) : ordering_(ordering_in) {}
+	template <typename Vertex, typename Graph> void discover_vertex(Vertex v, const Graph& g) const {
+		Key key = boost::get(boost::vertex_name, g, v);
+		ordering_.push_front(key);
+	}
+	std::list<Key>& ordering_;
+};
+
+/* ************************************************************************* */
+template<class Key>
+list<Key> predecessorMap2Keys(const PredecessorMap<Key>& p_map) {
+
+	typedef typename SGraph<Key>::Vertex SVertex;
+
+	SGraph<Key> g;
+	SVertex root;
+	std::map<Key, SVertex> key2vertex;
+	boost::tie(g, root, key2vertex) = gtsam::predecessorMap2Graph<SGraph<Key>, SVertex, Key>(p_map);
+
+	// breadth first visit on the graph
+	std::list<Key> keys;
+	ordering_key_visitor<Key> vis(keys);
+	boost::breadth_first_search(g, root, boost::visitor(vis));
+	return keys;
+}
+
+}
diff --git a/cpp/Ordering.cpp b/cpp/Ordering.cpp
index 1b24b6566..9f3a14fa0 100644
--- a/cpp/Ordering.cpp
+++ b/cpp/Ordering.cpp
@@ -10,7 +10,6 @@
 #include <boost/foreach.hpp>
 #include <boost/tuple/tuple.hpp>
 
-#include "graph-inl.h"
 #include "Ordering.h"
 
 
@@ -20,31 +19,6 @@ using namespace boost::assign;
 
 #define FOREACH_PAIR( KEY, VAL, COL) BOOST_FOREACH (boost::tie(KEY,VAL),COL)
 
-class ordering_key_visitor : public boost::default_bfs_visitor {
-public:
-	ordering_key_visitor(Ordering& ordering_in) : ordering_(ordering_in) {}
-	template <typename Vertex, typename Graph> void discover_vertex(Vertex v, const Graph& g) const {
-		string key = boost::get(boost::vertex_name, g, v);
-		ordering_.push_front(key);
-	}
-	Ordering& ordering_;
-};
-
-/* ************************************************************************* */
-Ordering::Ordering(const PredecessorMap<string>& p_map) {
-
-	typedef SGraph<string>::Vertex SVertex;
-
-	SGraph<string> g;
-	SVertex root;
-	map<string, SVertex> key2vertex;
-	boost::tie(g, root, key2vertex) = predecessorMap2Graph<SGraph<string>, SVertex, string>(p_map);
-
-	// breadth first visit on the graph
-	ordering_key_visitor vis(*this);
-	boost::breadth_first_search(g, root, boost::visitor(vis));
-}
-
 /* ************************************************************************* */
 Ordering Ordering::subtract(const Ordering& keys) const {
 	Ordering newOrdering = *this;
@@ -67,7 +41,3 @@ bool Ordering::equals(const Ordering &other, double tol) const {
 	return *this == other;
 }
 
-/* ************************************************************************* */
-
-
-
diff --git a/cpp/Ordering.h b/cpp/Ordering.h
index 029e61379..9682c54fd 100644
--- a/cpp/Ordering.h
+++ b/cpp/Ordering.h
@@ -40,11 +40,6 @@ namespace gtsam {
 			std::list<std::string>(strings_in) {
 		}
 
-		/**
-		 * Generate the ordering from a spanning tree represented by its parent map
-		 */
-		Ordering(const PredecessorMap<std::string>& p_map);
-
 		/**
 		 * Remove a set of keys from an ordering
 		 * @param keys to remove
@@ -63,4 +58,10 @@ namespace gtsam {
 
 	};
 
+	/**
+	 * Generate a list of keys from a spanning tree represented by its predecessor map
+	 */
+	template<class Key>
+	std::list<Key> predecessorMap2Keys(const PredecessorMap<Key>& p_map);
+
 }
diff --git a/cpp/testOrdering.cpp b/cpp/testOrdering.cpp
index 068c82783..2d70b275c 100644
--- a/cpp/testOrdering.cpp
+++ b/cpp/testOrdering.cpp
@@ -5,7 +5,9 @@
 
 #include <boost/assign/std/list.hpp> // for operator +=
 #include <CppUnitLite/TestHarness.h>
-#include "Ordering.h"
+#include "Ordering-inl.h"
+#include "Pose2Config.h"
+
 
 using namespace std;
 using namespace gtsam;
@@ -15,19 +17,25 @@ using namespace boost::assign;
 // x1 -> x2
 //		-> x3 -> x4
 //    -> x5
-TEST ( Ordering, constructorFromTree ) {
-	PredecessorMap<string> p_map;
-	p_map.insert(make_pair("x1", "x1"));
-	p_map.insert(make_pair("x2", "x1"));
-	p_map.insert(make_pair("x3", "x1"));
-	p_map.insert(make_pair("x4", "x3"));
-	p_map.insert(make_pair("x5", "x1"));
+TEST ( Ordering, predecessorMap2Keys ) {
+	typedef Symbol<Pose2,'x'> Key;
+	PredecessorMap<Key> p_map;
+	p_map.insert(make_pair(Key(1), Key(1)));
+	p_map.insert(make_pair(Key(2), Key(1)));
+	p_map.insert(make_pair(Key(3), Key(1)));
+	p_map.insert(make_pair(Key(4), Key(3)));
+	p_map.insert(make_pair(Key(5), Key(1)));
 
-	Ordering expected;
-	expected += "x4", "x5", "x3", "x2", "x1";
+	list<Key> expected;
+	expected += Key(4), Key(5), Key(3), Key(2), Key(1);
 
-	Ordering actual(p_map);
-	CHECK(assert_equal(expected, actual));
+	list<Key> actual = predecessorMap2Keys<Key>(p_map);
+	LONGS_EQUAL(expected.size(), actual.size());
+
+	list<Key>::const_iterator it1 = expected.begin();
+	list<Key>::const_iterator it2 = actual.begin();
+	for(; it1!=expected.end(); it1++, it2++)
+		CHECK(*it1 == *it2)
 }