From b325150b3751b7f5c43b0268f76be8e60f10fe38 Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Sun, 8 Dec 2024 16:18:42 -0500
Subject: [PATCH] revert DiscreteFactorGraph::product

---
 gtsam/discrete/DiscreteFactorGraph.cpp | 13 ++++---------
 gtsam/discrete/DiscreteFactorGraph.h   |  2 +-
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/gtsam/discrete/DiscreteFactorGraph.cpp b/gtsam/discrete/DiscreteFactorGraph.cpp
index fa9d9bdc7..9e64b0f6d 100644
--- a/gtsam/discrete/DiscreteFactorGraph.cpp
+++ b/gtsam/discrete/DiscreteFactorGraph.cpp
@@ -64,15 +64,10 @@ namespace gtsam {
   }
 
   /* ************************************************************************* */
-  DiscreteFactor::shared_ptr DiscreteFactorGraph::product() const {
-    sharedFactor result = this->at(0);
-    for (size_t i = 1; i < this->size(); ++i) {
-      const sharedFactor factor = this->at(i);
-      if (factor) {
-        // Predicated on the fact that all discrete factors are of a single type
-        // so there is no type-conversion happening which can be expensive.
-        result = result->operator*(factor);
-      }
+  DecisionTreeFactor DiscreteFactorGraph::product() const {
+    DecisionTreeFactor result;
+    for (const sharedFactor& factor : *this) {
+      if (factor) result = result * (*factor);
     }
     return result;
   }
diff --git a/gtsam/discrete/DiscreteFactorGraph.h b/gtsam/discrete/DiscreteFactorGraph.h
index a5324811c..43c48c2d0 100644
--- a/gtsam/discrete/DiscreteFactorGraph.h
+++ b/gtsam/discrete/DiscreteFactorGraph.h
@@ -147,7 +147,7 @@ class GTSAM_EXPORT DiscreteFactorGraph
   DiscreteKeys discreteKeys() const;
 
   /** return product of all factors as a single factor */
-  DiscreteFactor::shared_ptr product() const;
+  DecisionTreeFactor product() const;
 
   /** 
    * Evaluates the factor graph given values, returns the joint probability of