new AlgebraicDecisionTree constructor

gtsam/discrete/AlgebraicDecisionTree.h

@@ -182,6 +182,21 @@ namespace gtsam {
       this->root_ = DecisionTree<L, double>::convertFrom(other.root_, L_of_M, op);
     }
 
+    /**
+     * @brief Create from an arbitrary DecisionTree<L, X> by operating on it
+     * with a functional `f`.
+     *
+     * @tparam X The type of the leaf of the original DecisionTree
+     * @tparam Func Type signature of functional `f`.
+     * @param other The original DecisionTree from which the
+     * AlgbraicDecisionTree is constructed.
+     * @param f Functional used to operate on
+     * the leaves of the input DecisionTree.
+     */
+    template <typename X, typename Func>
+    AlgebraicDecisionTree(const DecisionTree<L, X>& other, Func f)
+        : Base(other, f) {}
+
     /** sum */
     AlgebraicDecisionTree operator+(const AlgebraicDecisionTree& g) const {
       return this->apply(g, &Ring::add);