From 453059bd61f4b08acdc43c37b9b098a5579d36a3 Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Sun, 5 Jan 2025 14:03:08 -0500
Subject: [PATCH] simplify to remove DiscreteProduct static function

---
 gtsam/discrete/DiscreteFactorGraph.cpp | 44 ++++++++++----------------
 1 file changed, 17 insertions(+), 27 deletions(-)

diff --git a/gtsam/discrete/DiscreteFactorGraph.cpp b/gtsam/discrete/DiscreteFactorGraph.cpp
index 0444f47ae..b3029111a 100644
--- a/gtsam/discrete/DiscreteFactorGraph.cpp
+++ b/gtsam/discrete/DiscreteFactorGraph.cpp
@@ -65,11 +65,23 @@ namespace gtsam {
 
   /* ************************************************************************ */
   DecisionTreeFactor DiscreteFactorGraph::product() const {
-    DiscreteFactor::shared_ptr result = *this->begin();
+    // PRODUCT: multiply all factors
+    gttic(product);
+    DiscreteFactor::shared_ptr product = *this->begin();
     for (auto it = this->begin() + 1; it != this->end(); ++it) {
-      if (*it) result = result->multiply(*it);
+      if (*it) product = product->multiply(*it);
     }
-    return result->toDecisionTreeFactor();
+    gttoc(product);
+
+    DecisionTreeFactor = result->toDecisionTreeFactor();
+
+    // Max over all the potentials by pretending all keys are frontal:
+    auto denominator = product.max(product.size());
+
+    // Normalize the product factor to prevent underflow.
+    product = product / (*denominator);
+
+    return product;
   }
 
   /* ************************************************************************ */
@@ -111,34 +123,12 @@ namespace gtsam {
 //      }
 //  }
 
-  /**
-   * @brief Multiply all the `factors`.
-   *
-   * @param factors The factors to multiply as a DiscreteFactorGraph.
-   * @return DecisionTreeFactor
-   */
-  static DecisionTreeFactor DiscreteProduct(
-      const DiscreteFactorGraph& factors) {
-    // PRODUCT: multiply all factors
-    gttic(product);
-    DecisionTreeFactor product = factors.product();
-    gttoc(product);
-
-    // Max over all the potentials by pretending all keys are frontal:
-    auto denominator = product.max(product.size());
-
-    // Normalize the product factor to prevent underflow.
-    product = product / (*denominator);
-
-    return product;
-  }
-
   /* ************************************************************************ */
   // Alternate eliminate function for MPE
   std::pair<DiscreteConditional::shared_ptr, DiscreteFactor::shared_ptr>  //
   EliminateForMPE(const DiscreteFactorGraph& factors,
                   const Ordering& frontalKeys) {
-    DecisionTreeFactor product = DiscreteProduct(factors);
+    DecisionTreeFactor product = factors.product();
 
     // max out frontals, this is the factor on the separator
     gttic(max);
@@ -216,7 +206,7 @@ namespace gtsam {
   std::pair<DiscreteConditional::shared_ptr, DiscreteFactor::shared_ptr>  //
   EliminateDiscrete(const DiscreteFactorGraph& factors,
                     const Ordering& frontalKeys) {
-    DecisionTreeFactor product = DiscreteProduct(factors);
+    DecisionTreeFactor product = factors.product();
 
     // sum out frontals, this is the factor on the separator
     gttic(sum);