diff --git a/gtsam/linear/NoiseModel.h b/gtsam/linear/NoiseModel.h
index 14886d64d..9577b2b09 100644
--- a/gtsam/linear/NoiseModel.h
+++ b/gtsam/linear/NoiseModel.h
@@ -75,10 +75,7 @@ namespace gtsam {
 			 */
 			virtual Vector unwhiten(const Vector& v) const = 0;
 
-      /**
-       * Mahalanobis distance v'*R'*R*v = <R*v,R*v>
-       */
-      virtual double Mahalanobis(const Vector& v) const = 0;
+      virtual double distance(const Vector& v) const = 0;
 
       virtual void WhitenSystem(Matrix& A, Vector& b) const = 0;
       virtual void WhitenSystem(Matrix& A1, Matrix& A2, Vector& b) const = 0;
@@ -168,6 +165,10 @@ namespace gtsam {
 			 */
 			virtual double Mahalanobis(const Vector& v) const;
 
+      inline virtual double distance(const Vector& v) const {
+        return Mahalanobis(v);
+      }
+
 			/**
 			 * Multiply a derivative with R (derivative of whiten)
 			 * Equivalent to whitening each column of the input matrix.
@@ -591,8 +592,8 @@ namespace gtsam {
       { return noise_->whiten(v); }
       inline virtual Vector unwhiten(const Vector& v) const
       { return noise_->unwhiten(v); }
-      inline virtual double Mahalanobis(const Vector& v) const
-      { return noise_->Mahalanobis(v); }
+      inline virtual double distance(const Vector& v) const
+      { return noise_->distance(v); }
       virtual void WhitenSystem(Matrix& A, Vector& b) const ;
       virtual void WhitenSystem(Matrix& A1, Matrix& A2, Vector& b) const ;
       virtual void WhitenSystem(Matrix& A1, Matrix& A2, Matrix& A3, Vector& b) const;
diff --git a/gtsam/nonlinear/NonlinearFactor.h b/gtsam/nonlinear/NonlinearFactor.h
index 87a586d37..eab7fcea2 100644
--- a/gtsam/nonlinear/NonlinearFactor.h
+++ b/gtsam/nonlinear/NonlinearFactor.h
@@ -217,7 +217,7 @@ namespace gtsam {
 		 * to transform it to (h(x)-z)^2/sigma^2, and then multiply by 0.5.
 		 */
 		virtual double error(const VALUES& c) const {
-			return 0.5 * noiseModel_->Mahalanobis(unwhitenedError(c));
+			return 0.5 * noiseModel_->distance(unwhitenedError(c));
 		}
 
 	private: