diff --git a/src/node_operators_binary.h b/src/node_operators_binary.h
index 38d9df4d..b80e6834 100644
--- a/src/node_operators_binary.h
+++ b/src/node_operators_binary.h
@@ -13,7 +13,17 @@ struct BinaryNodeOp : public Node {
    : Node(args...), a_(a), b_(b) {}
 
   void backward_numeric() {
-    backward();
+	using namespace std;
+	cerr << "BinaryNodeOp::" << typeid(*this).name() << "::backward_numeric" << endl;
+	cerr << "BEFORE:" << endl;
+	cerr << "a_->grad()=" << a_->grad().Debug() << endl;
+	cerr << "b_->grad()=" << b_->grad().Debug() << endl;
+	cerr << "adj_=" << adj_.Debug() << endl;
+	backward();
+	cerr << "AFTER:" << endl;
+	cerr << "a_->grad()=" << a_->grad().Debug() << endl;
+	cerr << "b_->grad()=" << b_->grad().Debug() << endl;
+	cerr << "adj_=" << adj_.Debug() << endl;
   }
 
 };
diff --git a/src/node_operators_unary.h b/src/node_operators_unary.h
index f810fe21..b7959f8d 100644
--- a/src/node_operators_unary.h
+++ b/src/node_operators_unary.h
@@ -12,7 +12,15 @@ struct UnaryNodeOp : public Node {
            args...), a_(a) {}
 
     void backward_numeric() {
+      using namespace std;
+  	cerr << "BinaryNodeOp::" << typeid(*this).name() << "::backward_numeric" << endl;
+      cerr << "BEFORE:" << endl;
+      cerr << "a_->grad()=" << a_->grad().Debug() << endl;
+      cerr << "adj_=" << adj_.Debug() << endl;
       backward();
+      cerr << "AFTER:" << endl;
+      cerr << "a_->grad()=" << a_->grad().Debug() << endl;
+      cerr << "adj_=" << adj_.Debug() << endl;
     }
 };
 
diff --git a/src/tensor.h b/src/tensor.h
index 3540bfdd..1ffcf0e1 100644
--- a/src/tensor.h
+++ b/src/tensor.h
@@ -405,17 +405,12 @@ class Tensor {
      */
     std::string Debug() const
     {
-    	return pimpl_->Debug();
-    }
-
-    /**
-     * @brief Print Tensor data on CPU (?) (const). 
-     */
-    void Print() const {
-      for (int i = 0; i < size(); ++i) {
-        std::cerr << (*this)[i] << " ";
-      }
-      std::cerr << std::endl;
+    	if (!pimpl_) {
+    		return "Not yet set";
+    	}
+    	else {
+    		return pimpl_->Debug();
+    	}
     }
 
     //void Load(const std::string &path);