Added one function emplace_shared

gtsam/inference/FactorGraph.h

@@ -33,6 +33,8 @@
 #include <gtsam/base/FastVector.h>
 #include <gtsam/inference/Key.h>
 
+#include <utility>
+
 namespace gtsam {
 
   // Forward declarations
@@ -159,6 +161,12 @@ namespace gtsam {
     void push_back(const sharedFactor& factor) {
       factors_.push_back(factor); }
 
+    /** Emplace a factor */
+    template<class DERIVEDFACTOR, class... Args>
+    void emplace_shared(Args&&... args) {
+        factors_.push_back(boost::make_shared<DERIVEDFACTOR>(std::forward<Args>(args)...));
+    }
+
     /** push back many factors with an iterator over shared_ptr (factors are not copied) */
     template<typename ITERATOR>
     typename boost::enable_if<boost::is_base_of<FactorType, typename ITERATOR::value_type::element_type> >::type
@@ -355,4 +363,4 @@ namespace gtsam {
 
 } // namespace gtsam
 
-#include <gtsam/inference/FactorGraph-inst.h>
+#include <gtsam/inference/FactorGraph-inst.h>