diff --git a/gtsam_unstable/nonlinear/Expression-inl.h b/gtsam_unstable/nonlinear/Expression-inl.h
index c2f51ea96..06405579e 100644
--- a/gtsam_unstable/nonlinear/Expression-inl.h
+++ b/gtsam_unstable/nonlinear/Expression-inl.h
@@ -185,7 +185,7 @@ public:
   virtual Augmented<T> forward(const Values& values) const = 0;
 
   /// Construct an execution trace for reverse AD
-  virtual std::pair<T, TracePtr> traceExecution(const Values& values) const = 0;
+  virtual T traceExecution(const Values& values, TracePtr& p) const = 0;
 };
 
 //-----------------------------------------------------------------------------
@@ -236,9 +236,10 @@ public:
   };
 
   /// Construct an execution trace for reverse AD
-  virtual std::pair<T, TracePtr> traceExecution(const Values& values) const {
+  virtual T traceExecution(const Values& values, TracePtr& p) const {
     Trace* trace = new Trace();
-    return std::make_pair(constant_, trace);
+    p = static_cast<TracePtr>(trace);
+    return constant_;
   }
 };
 
@@ -299,10 +300,11 @@ public:
   };
 
   /// Construct an execution trace for reverse AD
-  virtual std::pair<T, TracePtr> traceExecution(const Values& values) const {
+  virtual T traceExecution(const Values& values, TracePtr& p) const {
     Trace* trace = new Trace();
+    p = static_cast<TracePtr>(trace);
     trace->key = key_;
-    return std::make_pair(values.at<T>(key_), trace);
+    return values.at<T>(key_);
   }
 
 };
@@ -373,11 +375,11 @@ public:
   };
 
   /// Construct an execution trace for reverse AD
-  virtual std::pair<T, TracePtr> traceExecution(const Values& values) const {
-    A a;
+  virtual T traceExecution(const Values& values, TracePtr& p) const {
     Trace* trace = new Trace();
-    boost::tie(a, trace->trace) = this->expressionA_->traceExecution(values);
-    return std::make_pair(function_(a, trace->dTdA), trace);
+    p = static_cast<TracePtr>(trace);
+    A a = this->expressionA_->traceExecution(values,trace->trace);
+    return function_(a, trace->dTdA);
   }
 };
 
@@ -465,13 +467,12 @@ public:
   };
 
   /// Construct an execution trace for reverse AD
-  virtual std::pair<T, TracePtr> traceExecution(const Values& values) const {
-    A1 a1;
-    A2 a2;
+  virtual T traceExecution(const Values& values, TracePtr& p) const {
     Trace* trace = new Trace();
-    boost::tie(a1, trace->trace1) = this->expressionA1_->traceExecution(values);
-    boost::tie(a2, trace->trace2) = this->expressionA2_->traceExecution(values);
-    return std::make_pair(function_(a1, a2, trace->dTdA1, trace->dTdA2), trace);
+    p = static_cast<TracePtr>(trace);
+    A1 a1 = this->expressionA1_->traceExecution(values,trace->trace1);
+    A2 a2 = this->expressionA2_->traceExecution(values,trace->trace2);
+    return function_(a1, a2, trace->dTdA1, trace->dTdA2);
   }
 
 };
@@ -576,16 +577,13 @@ public:
   };
 
   /// Construct an execution trace for reverse AD
-  virtual std::pair<T, TracePtr> traceExecution(const Values& values) const {
-    A1 a1;
-    A2 a2;
-    A3 a3;
+  virtual T traceExecution(const Values& values, TracePtr& p) const {
     Trace* trace = new Trace();
-    boost::tie(a1, trace->trace1) = this->expressionA1_->traceExecution(values);
-    boost::tie(a2, trace->trace2) = this->expressionA2_->traceExecution(values);
-    boost::tie(a3, trace->trace3) = this->expressionA3_->traceExecution(values);
-    return std::make_pair(
-        function_(a1, a2, a3, trace->dTdA1, trace->dTdA2, trace->dTdA3), trace);
+    p = static_cast<TracePtr>(trace);
+    A1 a1 = this->expressionA1_->traceExecution(values,trace->trace1);
+    A2 a2 = this->expressionA2_->traceExecution(values,trace->trace2);
+    A3 a3 = this->expressionA3_->traceExecution(values,trace->trace3);
+    return function_(a1, a2, a3, trace->dTdA1, trace->dTdA2, trace->dTdA3);
   }
 
 };
diff --git a/gtsam_unstable/nonlinear/Expression.h b/gtsam_unstable/nonlinear/Expression.h
index cc7977a23..06265a9fb 100644
--- a/gtsam_unstable/nonlinear/Expression.h
+++ b/gtsam_unstable/nonlinear/Expression.h
@@ -117,9 +117,8 @@ public:
   Augmented<T> augmented(const Values& values) const {
 #define REVERSE_AD
 #ifdef REVERSE_AD
-    T value;
     TracePtr trace;
-    boost::tie(value,trace) = root_->traceExecution(values);
+    T value = root_->traceExecution(values,trace);
     Augmented<T> augmented(value);
     trace->reverseAD(augmented.jacobians());
     delete trace;