diff --git a/gtsam/discrete/DiscreteBayesNet.cpp b/gtsam/discrete/DiscreteBayesNet.cpp
index bce14ad46..bef0413c8 100644
--- a/gtsam/discrete/DiscreteBayesNet.cpp
+++ b/gtsam/discrete/DiscreteBayesNet.cpp
@@ -18,6 +18,7 @@
 
 #include <gtsam/discrete/DiscreteBayesNet.h>
 #include <gtsam/discrete/DiscreteConditional.h>
+#include <gtsam/discrete/DiscreteLookupDAG.h>
 #include <gtsam/inference/FactorGraph-inst.h>
 
 namespace gtsam {
@@ -56,18 +57,15 @@ DiscreteValues DiscreteBayesNet::sample() const {
 
 DiscreteValues DiscreteBayesNet::sample(DiscreteValues result) const {
   // sample each node in turn in topological sort order (parents first)
-  for (auto it = std::make_reverse_iterator(end()); it != std::make_reverse_iterator(begin()); ++it) {
+  for (auto it = std::make_reverse_iterator(end());
+       it != std::make_reverse_iterator(begin()); ++it) {
     (*it)->sampleInPlace(&result);
   }
   return result;
 }
 
 DiscreteValues DiscreteBayesNet::mode() const {
-  DiscreteValues result;
-  for (auto it = begin(); it != end(); ++it) {
-    result[(*it)->firstFrontalKey()] = (*it)->argmax(result);
-  }
-  return result;
+  return DiscreteLookupDAG::FromBayesNet(*this).argmax();
 }
 
 /* *********************************************************************** */