1 files changed, 5 insertions, 2 deletions
diff --git a/extern/ceres/include/ceres/autodiff_cost_function.h b/extern/ceres/include/ceres/autodiff_cost_function.h
index 207f0a41688..cd256432a98 100644
--- a/extern/ceres/include/ceres/autodiff_cost_function.h
+++ b/extern/ceres/include/ceres/autodiff_cost_function.h
@@ -151,7 +151,8 @@ namespace ceres {
 template <typename CostFunctor,
           int kNumResiduals,  // Number of residuals, or ceres::DYNAMIC.
           int... Ns>          // Number of parameters in each parameter block.
-class AutoDiffCostFunction : public SizedCostFunction<kNumResiduals, Ns...> {
+class AutoDiffCostFunction final
+    : public SizedCostFunction<kNumResiduals, Ns...> {
  public:
   // Takes ownership of functor by default. Uses the template-provided
   // value for the number of residuals ("kNumResiduals").
@@ -178,7 +179,7 @@ class AutoDiffCostFunction : public SizedCostFunction<kNumResiduals, Ns...> {
     SizedCostFunction<kNumResiduals, Ns...>::set_num_residuals(num_residuals);
   }
 
-  explicit AutoDiffCostFunction(AutoDiffCostFunction&& other)
+  AutoDiffCostFunction(AutoDiffCostFunction&& other)
       : functor_(std::move(other.functor_)), ownership_(other.ownership_) {}
 
   virtual ~AutoDiffCostFunction() {
@@ -215,6 +216,8 @@ class AutoDiffCostFunction : public SizedCostFunction<kNumResiduals, Ns...> {
         jacobians);
   };
 
+  const CostFunctor& functor() const { return *functor_; }
+
  private:
   std::unique_ptr<CostFunctor> functor_;
   Ownership ownership_;