diff --git a/gtsam/hybrid/GaussianMixtureFactor.cpp b/gtsam/hybrid/GaussianMixtureFactor.cpp
index fb931c5e5..746c883b2 100644
--- a/gtsam/hybrid/GaussianMixtureFactor.cpp
+++ b/gtsam/hybrid/GaussianMixtureFactor.cpp
@@ -81,12 +81,24 @@ void GaussianMixtureFactor::print(const std::string &s,
 }
 
 /* *******************************************************************************/
-const GaussianMixtureFactor::Mixture GaussianMixtureFactor::factors() const {
-  return Mixture(factors_, [](const FactorAndConstant &factor_z) {
-    return factor_z.factor;
-  });
+GaussianFactor::shared_ptr GaussianMixtureFactor::factor(
+    const DiscreteValues &assignment) const {
+  return factors_(assignment).factor;
 }
 
+/* *******************************************************************************/
+double GaussianMixtureFactor::constant(const DiscreteValues &assignment) const {
+  return factors_(assignment).constant;
+}
+
+/* *******************************************************************************/
+// NOTE(dellaert): this was not used and is expensive.
+// const GaussianMixtureFactor::Mixture GaussianMixtureFactor::factors() const {
+//   return Mixture(factors_, [](const FactorAndConstant &factor_z) {
+//     return factor_z.factor;
+//   });
+// }
+
 /* *******************************************************************************/
 GaussianMixtureFactor::Sum GaussianMixtureFactor::add(
     const GaussianMixtureFactor::Sum &sum) const {
diff --git a/gtsam/hybrid/GaussianMixtureFactor.h b/gtsam/hybrid/GaussianMixtureFactor.h
index f0f8d060d..7e9edbe86 100644
--- a/gtsam/hybrid/GaussianMixtureFactor.h
+++ b/gtsam/hybrid/GaussianMixtureFactor.h
@@ -151,12 +151,16 @@ class GTSAM_EXPORT GaussianMixtureFactor : public HybridFactor {
   void print(
       const std::string &s = "GaussianMixtureFactor\n",
       const KeyFormatter &formatter = DefaultKeyFormatter) const override;
+
   /// @}
   /// @name Standard API
   /// @{
 
-  /// Getter for the underlying Gaussian Factor Decision Tree.
-  const Mixture factors() const;
+  /// Get factor at a given discrete assignment.
+  sharedFactor factor(const DiscreteValues &assignment) const;
+
+  /// Get constant at a given discrete assignment.
+  double constant(const DiscreteValues &assignment) const;
 
   /**
    * @brief Combine the Gaussian Factor Graphs in `sum` and `this` while