diff --git a/cpp/FactorGraph-inl.h b/cpp/FactorGraph-inl.h
index af20cc8e6..ba4e4b752 100644
--- a/cpp/FactorGraph-inl.h
+++ b/cpp/FactorGraph-inl.h
@@ -331,9 +331,8 @@ map<string, string> FactorGraph<Factor>::findMinimumSpanningTree() const {
 }
 
 template<class Factor>
-pair<FactorGraph<Factor>, FactorGraph<Factor> > FactorGraph<Factor>::split(map<string, string> tree) const {
+void FactorGraph<Factor>::split(map<string, string> tree, FactorGraph<Factor>& Ab1, FactorGraph<Factor>& Ab2) const {
 
-	FactorGraph<Factor> Ab1, Ab2;
 	BOOST_FOREACH(sharedFactor factor, factors_){
 		if (factor->keys().size() > 2)
 			throw(invalid_argument("split: only support factors with at most two keys"));
@@ -350,8 +349,6 @@ pair<FactorGraph<Factor>, FactorGraph<Factor> > FactorGraph<Factor>::split(map<s
 		else
 			Ab2.push_back(factor);
 	}
-
-	return make_pair(Ab1, Ab2);
 }
 
 
diff --git a/cpp/FactorGraph.h b/cpp/FactorGraph.h
index 518c33c82..0681716a2 100644
--- a/cpp/FactorGraph.h
+++ b/cpp/FactorGraph.h
@@ -125,7 +125,8 @@ namespace gtsam {
 		 * Split the graph into two parts: one corresponds to the given spanning tre,
 		 * and the other corresponds to the rest of the factors
 		 */
-		std::pair<FactorGraph<Factor>, FactorGraph<Factor> > split(std::map<std::string, std::string> tree) const;
+		void split(std::map<std::string, std::string> tree,
+				FactorGraph<Factor>& Ab1, FactorGraph<Factor>& Ab2) const;
 
 	private:
 		/** Associate factor index with the variables connected to the factor */
diff --git a/cpp/GaussianBayesNet.cpp b/cpp/GaussianBayesNet.cpp
index d745ae8a7..1799aa553 100644
--- a/cpp/GaussianBayesNet.cpp
+++ b/cpp/GaussianBayesNet.cpp
@@ -64,6 +64,8 @@ VectorConfig optimize(const GaussianBayesNet& bn)
 	
   /** solve each node in turn in topological sort order (parents first)*/
 	BOOST_REVERSE_FOREACH(GaussianConditional::shared_ptr cg, bn) {
+		cg->print();
+		result.print();
     Vector x = cg->solve(result); // Solve for that variable
     result.insert(cg->key(),x);   // store result in partial solution
   }
diff --git a/cpp/testGaussianFactorGraph.cpp b/cpp/testGaussianFactorGraph.cpp
index 60164ec80..a013c3f8c 100644
--- a/cpp/testGaussianFactorGraph.cpp
+++ b/cpp/testGaussianFactorGraph.cpp
@@ -769,9 +769,7 @@ TEST( GaussianFactorGraph, split )
 	tree["x4"] = "x1";
 
 	GaussianFactorGraph Ab1, Ab2;
-	pair<FactorGraph<GaussianFactor>, FactorGraph<GaussianFactor> > gg = g.split(tree);
-	Ab1 = *reinterpret_cast<GaussianFactorGraph*>(&(gg.first));
-	Ab2 = *reinterpret_cast<GaussianFactorGraph*>(&(gg.second));
+  g.split(tree, Ab1, Ab2);
 	LONGS_EQUAL(3, Ab1.size());
 	LONGS_EQUAL(2, Ab2.size());
 }