diff --git a/gtsam/inference/BayesNet-inst.h b/gtsam/inference/BayesNet-inst.h
index a73762258..4674b0083 100644
--- a/gtsam/inference/BayesNet-inst.h
+++ b/gtsam/inference/BayesNet-inst.h
@@ -35,21 +35,39 @@ void BayesNet<CONDITIONAL>::print(
 
 /* ************************************************************************* */
 template <class CONDITIONAL>
-void BayesNet<CONDITIONAL>::saveGraph(const std::string& s,
-                                      const KeyFormatter& keyFormatter) const {
-  std::ofstream of(s.c_str());
-  of << "digraph G{\n";
+void BayesNet<CONDITIONAL>::dot(std::ostream& os,
+                                const KeyFormatter& keyFormatter) const {
+  os << "digraph G{\n";
 
   for (auto conditional : boost::adaptors::reverse(*this)) {
     typename CONDITIONAL::Frontals frontals = conditional->frontals();
-    Key me = frontals.front();
-    typename CONDITIONAL::Parents parents = conditional->parents();
-    for (Key p : parents)
-      of << keyFormatter(p) << "->" << keyFormatter(me) << std::endl;
+    const Key me = frontals.front();
+    auto parents = conditional->parents();
+    for (const Key& p : parents)
+      os << keyFormatter(p) << "->" << keyFormatter(me) << "\n";
   }
 
-  of << "}";
+  os << "}";
+  std::flush(os);
+}
+
+/* ************************************************************************* */
+template <class CONDITIONAL>
+std::string BayesNet<CONDITIONAL>::dot(const KeyFormatter& keyFormatter) const {
+  std::stringstream ss;
+  dot(ss, keyFormatter);
+  return ss.str();
+}
+
+/* ************************************************************************* */
+template <class CONDITIONAL>
+void BayesNet<CONDITIONAL>::saveGraph(const std::string& filename,
+                                      const KeyFormatter& keyFormatter) const {
+  std::ofstream of(filename.c_str());
+  dot(of, keyFormatter);
   of.close();
 }
 
+/* ************************************************************************* */
+
 }  // namespace gtsam
diff --git a/gtsam/inference/BayesNet.h b/gtsam/inference/BayesNet.h
index 938278d5a..e430b3fe4 100644
--- a/gtsam/inference/BayesNet.h
+++ b/gtsam/inference/BayesNet.h
@@ -67,8 +67,19 @@ namespace gtsam {
    /// @name Standard Interface
    /// @{
 
-   void saveGraph(const std::string& s,
+   /// Output to graphviz format, stream version.
+   virtual void dot(std::ostream& os, const KeyFormatter& keyFormatter =
+                                          DefaultKeyFormatter) const;
+
+   /// Output to graphviz format string.
+   std::string dot(
+       const KeyFormatter& keyFormatter = DefaultKeyFormatter) const;
+
+   /// output to file with graphviz format.
+   void saveGraph(const std::string& filename,
                   const KeyFormatter& keyFormatter = DefaultKeyFormatter) const;
+  
+   /// @}
   };
 
 }