diff --git a/Source/Rbm.cpp b/Source/Rbm.cpp
index 7858895..ddc8039 100644
--- a/Source/Rbm.cpp
+++ b/Source/Rbm.cpp
@@ -261,11 +261,14 @@ void Rbm::train(size_t numEpochs, size_t miniBatchSize, bool &doStop)
 	
 	updateHiddenBatch();
 	
-	MatrixXd vis = m_h * m_w.weights().transpose();
+	MatrixXd h = __batch * m_w.weights();
+	h += m_w.hiddenBias().replicate(__batch.rows(), 1);
+	
+	MatrixXd vis = h * m_w.weights().transpose();
 	vis += m_w.visibleBias().replicate(__batch.rows(), 1);
 	MatrixXd diffErr = __batch - probsLogistic(vis);
 	diffErr.array() *= diffErr.array();
-	double err = diffErr.colwise().sum().mean();
+	double err = diffErr.array().mean();
 	cout << "error (total) = " << err << endl;
 
 	onProgressChanged();