From a71008d7fd572b679c7816f19f707d2d2770c3b8 Mon Sep 17 00:00:00 2001
From: Varun Agrawal <varagrawal@gmail.com>
Date: Tue, 31 Dec 2024 20:35:36 -0500
Subject: [PATCH] new helper constructor for DiscreteConditional

---
 gtsam/discrete/DiscreteConditional.cpp | 11 ++++++++++-
 gtsam/discrete/DiscreteConditional.h   | 11 +++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/gtsam/discrete/DiscreteConditional.cpp b/gtsam/discrete/DiscreteConditional.cpp
index eeb5dca3f..8396b10e0 100644
--- a/gtsam/discrete/DiscreteConditional.cpp
+++ b/gtsam/discrete/DiscreteConditional.cpp
@@ -24,13 +24,13 @@
 #include <gtsam/hybrid/HybridValues.h>
 
 #include <algorithm>
+#include <cassert>
 #include <random>
 #include <set>
 #include <stdexcept>
 #include <string>
 #include <utility>
 #include <vector>
-#include <cassert>
 
 using namespace std;
 using std::pair;
@@ -47,6 +47,15 @@ DiscreteConditional::DiscreteConditional(const size_t nrFrontals,
                                          const DecisionTreeFactor& f)
     : BaseFactor(f / (*f.sum(nrFrontals))), BaseConditional(nrFrontals) {}
 
+/* ************************************************************************** */
+DiscreteConditional::DiscreteConditional(size_t nrFrontals,
+                                         const DecisionTreeFactor& f,
+                                         const Ordering& orderedKeys)
+    : BaseFactor(f), BaseConditional(nrFrontals) {
+  keys_.clear();
+  keys_.insert(keys_.end(), orderedKeys.begin(), orderedKeys.end());
+}
+
 /* ************************************************************************** */
 DiscreteConditional::DiscreteConditional(size_t nrFrontals,
                                          const DiscreteKeys& keys,
diff --git a/gtsam/discrete/DiscreteConditional.h b/gtsam/discrete/DiscreteConditional.h
index 3ec9ae590..549504985 100644
--- a/gtsam/discrete/DiscreteConditional.h
+++ b/gtsam/discrete/DiscreteConditional.h
@@ -56,6 +56,17 @@ class GTSAM_EXPORT DiscreteConditional
   /// Construct from factor, taking the first `nFrontals` keys as frontals.
   DiscreteConditional(size_t nFrontals, const DecisionTreeFactor& f);
 
+  /**
+   * @brief Construct from DecisionTreeFactor,
+   * taking the first `nrFrontals` from `orderedKeys`.
+   *
+   * @param nrFrontals The number of frontal variables.
+   * @param f The DecisionTreeFactor to construct from.
+   * @param orderedKeys Ordered list of keys involved in the conditional.
+   */
+  DiscreteConditional(size_t nrFrontals, const DecisionTreeFactor& f,
+                      const Ordering& orderedKeys);
+
   /**
    * Construct from DiscreteKeys and AlgebraicDecisionTree, taking the first
    * `nFrontals` keys as frontals, in the order given.