diff --git a/src/node_operators.h b/src/node_operators.h
index e7994c0a..2d675ae8 100644
--- a/src/node_operators.h
+++ b/src/node_operators.h
@@ -114,7 +114,7 @@ struct LogitNodeOp : public UnaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"logit\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -138,7 +138,7 @@ struct TanhNodeOp : public UnaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"tanh\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -179,7 +179,7 @@ struct SoftmaxNodeOp : public UnaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"softmax\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -208,7 +208,7 @@ struct ArgmaxNodeOp : public UnaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"argmax\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -231,7 +231,7 @@ struct LogNodeOp : public UnaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"log\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -254,7 +254,7 @@ struct ExpNodeOp : public UnaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"exp\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -276,7 +276,7 @@ struct NegNodeOp : public UnaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"-\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -329,8 +329,8 @@ struct DotNodeOp : public BinaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"×\", style=\"filled\", fillcolor=\"orange\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl;
-    ss << "\"" << &*b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl;
+    ss << "\"" << b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -356,8 +356,8 @@ struct PlusNodeOp : public BinaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"+\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl;
-    ss << "\"" << &*b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl;
+    ss << "\"" << b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -383,8 +383,8 @@ struct MinusNodeOp : public BinaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"-\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl;
-    ss << "\"" << &*b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl;
+    ss << "\"" << b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
@@ -410,8 +410,8 @@ struct MultNodeOp : public BinaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"•\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << &*a_ << "\" -> \"" << this << "\"" << std::endl;
-    ss << "\"" << &*b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl;
+    ss << "\"" << b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 
diff --git a/src/optimizers.h b/src/optimizers.h
index a977d7f8..6bfe7861 100644
--- a/src/optimizers.h
+++ b/src/optimizers.h
@@ -6,9 +6,15 @@
 
 namespace marian {
 
+// @TODO: modify computation graph to group all paramters in single matrix object.
+// This will allow to perform a single large SGD update per batch. Currently there
+// are as many updates as different paramters.
+
+// @TODO: Implement Element(...) with multiple functors for compacting of calls.
+
 class Sgd {
   public:
-    Sgd(float eta=0.001) : eta_(eta) {}
+    Sgd(float eta=0.01) : eta_(eta) {}
     
     void operator()(ExpressionGraph& graph, int batchSize) {
       graph.backprop(batchSize);
@@ -25,7 +31,7 @@ class Sgd {
 // @TODO: Add serialization for historic gradients and parameters
 class Adagrad {
   public:
-    Adagrad(float eta=0.001, float eps=10e-8)
+    Adagrad(float eta=0.01, float eps=10e-8)
     : eta_(eta), eps_(eps) {}
     
     void operator()(ExpressionGraph& graph, int batchSize) {
diff --git a/src/train_mnist.cu b/src/train_mnist.cu
index 5b32cc9f..c4b932c0 100644
--- a/src/train_mnist.cu
+++ b/src/train_mnist.cu
@@ -27,7 +27,7 @@ int main(int argc, char** argv) {
   auto cost = named(-mean(sum(y * log(lr), axis=1), axis=0), "cost");
   std::cerr << "lr=" << lr.Debug() << std::endl;
 
-  Adagrad opt;
+  Adam opt;
   opt(g, 300);
   
   return 0;
diff --git a/src/validate_mnist.cu b/src/validate_mnist.cu
index 34364929..0f8e0482 100644
--- a/src/validate_mnist.cu
+++ b/src/validate_mnist.cu
@@ -62,7 +62,7 @@ int main(int argc, char** argv) {
   g["x"] = (xt << testImages);
   g["y"] = (yt << testLabels);
   
-  Adam opt;
+  Adagrad opt;
   for(size_t j = 0; j < 20; ++j) {
     for(size_t i = 0; i < 60; ++i) {
       opt(g, BATCH_SIZE);
@@ -70,8 +70,6 @@ int main(int argc, char** argv) {
     std::cerr << g["cost"].val()[0] << std::endl;
   }
   
-  //std::cout << g.graphviz() << std::endl;
-  
   std::vector<float> results;
   results << g["probs"].val();
   
@@ -80,8 +78,10 @@ int main(int argc, char** argv) {
     size_t correct = 0;
     size_t proposed = 0;
     for (size_t j = 0; j < LABEL_SIZE; ++j) {
-      if (testLabels[i+j]) correct = j;
-      if (results[i + j] > results[i + proposed]) proposed = j;
+      if (testLabels[i+j])
+        correct = j;
+      if (results[i + j] > results[i + proposed])
+        proposed = j;
     }
     acc += (correct == proposed);
   }