diff --git a/source/DeepStack.cpp b/source/DeepStack.cpp
index 62f999e..40a63f9 100644
--- a/source/DeepStack.cpp
+++ b/source/DeepStack.cpp
@@ -87,14 +87,12 @@ arma::mat DeepStack::upDownPass(size_t layerId, const arma::mat& v)
 
 arma::mat DeepStack::upPass(Layer *pLayer, arma::mat const &v)
 {
-	arma::mat h = arma::zeros(0,0);
-	arma::mat tv = v;
+	arma::mat h = v;
 	while(pLayer)
 	{
 		if (pLayer->isEnable())
 		{
-			h = pLayer->to_h_gibbs(tv);
-			tv = h;
+			h = pLayer->to_h_gibbs(h);
 		}
 		pLayer = pLayer->next;
 	}
@@ -103,14 +101,12 @@ arma::mat DeepStack::upPass(Layer *pLayer, arma::mat const &v)
 
 arma::mat DeepStack::downPass(Layer *pLayer, arma::mat const &h)
 {
-	arma::mat v = arma::zeros(0,0);
-	arma::mat th = h;
+	arma::mat v = h;
 	while(pLayer)
 	{
 		if (pLayer->isEnable())
 		{
-			v = pLayer->to_v_gibbs(th);
-			th = v;
+			v = pLayer->to_v_gibbs(v);
 		}
 		pLayer = pLayer->prev;
 	}