function to save graph as graphviz file via wrapper

gtsam/gtsam.i

@@ -2041,6 +2041,7 @@ class NonlinearFactorGraph {
 
   // enabling serialization functionality
   void serialize() const;
+  void saveGraph(const string& s) const;
 };
 
 #include <gtsam/nonlinear/NonlinearFactor.h>

gtsam/nonlinear/NonlinearFactorGraph.cpp

@@ -34,6 +34,7 @@
 #endif
 
 #include <cmath>
+#include <fstream>
 #include <limits>
 
 using namespace std;
@@ -256,6 +257,16 @@ void NonlinearFactorGraph::saveGraph(std::ostream &stm, const Values& values,
   stm << "}\n";
 }
 
+/* ************************************************************************* */
+void NonlinearFactorGraph::saveGraph(
+    const std::string& file, const Values& values,
+    const GraphvizFormatting& graphvizFormatting,
+    const KeyFormatter& keyFormatter) const {
+  std::ofstream of(file);
+  saveGraph(of, values, graphvizFormatting, keyFormatter);
+  of.close();
+}
+
 /* ************************************************************************* */
 double NonlinearFactorGraph::error(const Values& values) const {
   gttic(NonlinearFactorGraph_error);

gtsam/nonlinear/NonlinearFactorGraph.h

@@ -11,7 +11,7 @@
 
 /**
  * @file    NonlinearFactorGraph.h
- * @brief   Factor Graph Constsiting of non-linear factors
+ * @brief   Factor Graph consisting of non-linear factors
  * @author  Frank Dellaert
  * @author  Carlos Nieto
  * @author  Christian Potthast
@@ -115,6 +115,11 @@ namespace gtsam {
     void saveGraph(std::ostream& stm, const Values& values = Values(),
       const GraphvizFormatting& graphvizFormatting = GraphvizFormatting(),
       const KeyFormatter& keyFormatter = DefaultKeyFormatter) const;
+  
+    /** Write the graph in GraphViz format to file for visualization */
+    void saveGraph(const std::string& file, const Values& values = Values(),
+      const GraphvizFormatting& graphvizFormatting = GraphvizFormatting(),
+      const KeyFormatter& keyFormatter = DefaultKeyFormatter) const;
 
     /** unnormalized error, \f$ 0.5 \sum_i (h_i(X_i)-z)^2/\sigma^2 \f$ in the most common case */
     double error(const Values& values) const;