add using NonlinearFactor::error

gtsam/constraint/NonlinearConstraint.h

@@ -40,6 +40,8 @@ class GTSAM_EXPORT NonlinearConstraint : public NoiseModelFactor {
   /** Use constructors of NoiseModelFactor. */
   using Base::Base;
 
+  using NonlinearFactor::error;
+
   /** Destructor. */
   virtual ~NonlinearConstraint() {}
 

gtsam/nonlinear/NonlinearFactor.h

@@ -280,6 +280,8 @@ public:
    */
   double weight(const Values& c) const;
 
+  using NonlinearFactor::error;
+
   /**
    * Calculate the error of the factor.
    * This is the log-likelihood, e.g. \f$ 0.5(h(x)-z)^2/\sigma^2 \f$ in case of Gaussian.