diff --git a/CMakeLists.txt b/CMakeLists.txt
index 43159a935..39eefa6e6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,9 +6,6 @@ if(NOT DEFINED CMAKE_MACOSX_RPATH)
   set(CMAKE_MACOSX_RPATH 0)
 endif()
 
-add_definitions(-Wno-deprecated-declarations)
-add_definitions(-ftemplate-backtrace-limit=0)
-
 set(CMAKE_CXX_STANDARD 17)
 
 # Set the version number for the library
diff --git a/gtsam/base/OptionalJacobian.h b/gtsam/base/OptionalJacobian.h
index 88718bb01..d6f0db500 100644
--- a/gtsam/base/OptionalJacobian.h
+++ b/gtsam/base/OptionalJacobian.h
@@ -92,12 +92,12 @@ public:
   }
 
   /// Constructor that will resize a dynamic matrix (unless already correct)
-  OptionalJacobian(Eigen::MatrixXd* dynamic) :
-      map_(nullptr) {
-	if (dynamic) {
-      dynamic->resize(Rows, Cols); // no malloc if correct size
+  OptionalJacobian(Eigen::MatrixXd* dynamic)
+      : map_(nullptr) {
+    if (dynamic) {
+      dynamic->resize(Rows, Cols);  // no malloc if correct size
       usurp(dynamic->data());
-	}
+    }
   }
 
   /**
diff --git a/gtsam/navigation/ConstantVelocityFactor.h b/gtsam/navigation/ConstantVelocityFactor.h
index 536268e5c..8bb76379a 100644
--- a/gtsam/navigation/ConstantVelocityFactor.h
+++ b/gtsam/navigation/ConstantVelocityFactor.h
@@ -31,6 +31,7 @@ class ConstantVelocityFactor : public NoiseModelFactorN<NavState, NavState> {
 
    public:
     using Base = NoiseModelFactor2<NavState, NavState>;
+    // Provide access to the Matrix& version of evaluateError:
     using Base::evaluateError;
 
    public:
diff --git a/gtsam/nonlinear/ExpressionFactor.h b/gtsam/nonlinear/ExpressionFactor.h
index 650bedfb1..e5df25ca9 100644
--- a/gtsam/nonlinear/ExpressionFactor.h
+++ b/gtsam/nonlinear/ExpressionFactor.h
@@ -55,6 +55,7 @@ protected:
 
 
  public:
+  // Provide access to the Matrix& version of unwhitenedError:
   using NoiseModelFactor::unwhitenedError;
   typedef boost::shared_ptr<ExpressionFactor<T> > shared_ptr;
 
@@ -244,6 +245,8 @@ class ExpressionFactorN : public ExpressionFactor<T> {
 public:
   static const std::size_t NARY_EXPRESSION_SIZE = sizeof...(Args);
   using ArrayNKeys = std::array<Key, NARY_EXPRESSION_SIZE>;
+    
+  // Provide access to the Matrix& version of unwhitenedError:
   using ExpressionFactor<T>::unwhitenedError;
 
   /// Destructor
diff --git a/gtsam/nonlinear/NonlinearEquality.h b/gtsam/nonlinear/NonlinearEquality.h
index 1d3282dd9..c026530ec 100644
--- a/gtsam/nonlinear/NonlinearEquality.h
+++ b/gtsam/nonlinear/NonlinearEquality.h
@@ -46,6 +46,7 @@ class NonlinearEquality: public NoiseModelFactorN<VALUE> {
 
 public:
   typedef VALUE T;
+  // Provide access to the Matrix& version of evaluateError:
   using NoiseModelFactor1<VALUE>::evaluateError;
 
 private:
diff --git a/gtsam/nonlinear/NonlinearFactor.h b/gtsam/nonlinear/NonlinearFactor.h
index be1fbb889..3c03b717b 100644
--- a/gtsam/nonlinear/NonlinearFactor.h
+++ b/gtsam/nonlinear/NonlinearFactor.h
@@ -247,8 +247,12 @@ public:
   virtual Vector unwhitenedError(const Values& x, OptionalMatrixVecType H = OptionalMatrixVecNone) const = 0;
 
   // support taking in the actual vector instead of the pointer as well
+  // to get access to this version of the function from derived classes
+  // one will need to use the "using" keyword and specify that like this:
+  // public:
+  //   using NoiseModelFactor::unwhitenedError;
   Vector unwhitenedError(const Values& x, std::vector<Matrix>& H) const {
-	  return unwhitenedError(x, &H);
+    return unwhitenedError(x, &H);
   }
 
   /**
@@ -593,10 +597,14 @@ protected:
   virtual Vector evaluateError(const ValueTypes&... x,
                                OptionalMatrixTypeT<ValueTypes>... H) const = 0;
 
-  // if someone uses the evaluateError function by supplying all the optional
+  // If someone uses the evaluateError function by supplying all the optional
   // arguments then redirect the call to the one which takes pointers
+  // to get access to this version of the function from derived classes
+  // one will need to use the "using" keyword and specify that like this:
+  // public:
+  //   using NoiseModelFactorN<list the value types here>::evaluateError;
   Vector evaluateError(const ValueTypes&... x, MatrixTypeT<ValueTypes>&... H) const {
-	  return evaluateError(x..., (&H)...);
+    return evaluateError(x..., (&H)...);
   }
 
   /// @}
@@ -619,19 +627,23 @@ protected:
    */
   template <typename... OptionalJacArgs, typename = IndexIsValid<sizeof...(OptionalJacArgs) + 1>>
   inline Vector evaluateError(const ValueTypes&... x, OptionalJacArgs&&... H) const {
-	// A check to ensure all arguments passed are all either matrices or are all pointers to matrices
+    // A check to ensure all arguments passed are either matrices or are all pointers to matrices
     constexpr bool are_all_mat = (... && (std::is_same<Matrix, std::decay_t<OptionalJacArgs>>::value));
+    // The pointers can either be of std::nonetype_t or of Matrix* type
     constexpr bool are_all_ptrs = (... && (std::is_same<OptionalMatrixType, std::decay_t<OptionalJacArgs>>::value ||
                                            std::is_same<OptionalNoneType, std::decay_t<OptionalJacArgs>>::value));
     static_assert((are_all_mat || are_all_ptrs),
                   "Arguments that are passed to the evaluateError function can only be of following the types: Matrix, "
                   "or Matrix*");
-	// if they pass all matrices then we want to pass their pointers instead
-	if constexpr (are_all_mat) {
-		return evaluateError(x..., (&H)...);
-	} else {
-    return evaluateError(x..., std::forward<OptionalJacArgs>(H)..., static_cast<OptionalMatrixType>(OptionalNone));
-	}
+    // if they pass all matrices then we want to pass their pointers instead
+    if constexpr (are_all_mat) {
+      return evaluateError(x..., (&H)...);
+    } else {
+      // If they are pointer version, ensure to cast them all to be Matrix* types
+      // This will ensure any arguments inferred as std::nonetype_t are cast to (Matrix*) nullptr
+      // This guides the compiler to the correct overload which is the one that takes pointers
+      return evaluateError(x..., std::forward<OptionalJacArgs>(H)..., static_cast<OptionalMatrixType>(OptionalNone));
+    }
   }
 
   /// @}
diff --git a/gtsam/nonlinear/PriorFactor.h b/gtsam/nonlinear/PriorFactor.h
index 2c6161760..0a97ab39e 100644
--- a/gtsam/nonlinear/PriorFactor.h
+++ b/gtsam/nonlinear/PriorFactor.h
@@ -31,7 +31,8 @@ namespace gtsam {
 
   public:
     typedef VALUE T;
-	using NoiseModelFactor1<VALUE>::evaluateError;
+    // Provide access to the Matrix& version of evaluateError:
+	  using NoiseModelFactor1<VALUE>::evaluateError;
 
   private:
 
diff --git a/gtsam/nonlinear/tests/CMakeLists.txt b/gtsam/nonlinear/tests/CMakeLists.txt
index 4a4aff4b4..69a3700f2 100644
--- a/gtsam/nonlinear/tests/CMakeLists.txt
+++ b/gtsam/nonlinear/tests/CMakeLists.txt
@@ -1 +1 @@
-gtsamAddTestsGlob(nonlinear "test*.cpp" "${tests_exclude}" "gtsam")
+gtsamAddTestsGlob(nonlinear "test*.cpp" "" "gtsam")
diff --git a/gtsam/sam/BearingFactor.h b/gtsam/sam/BearingFactor.h
index 670e25d84..68d6cbd48 100644
--- a/gtsam/sam/BearingFactor.h
+++ b/gtsam/sam/BearingFactor.h
@@ -65,7 +65,7 @@ struct BearingFactor : public ExpressionFactorN<T, A1, A2> {
     OptionalMatrixType H1 = OptionalNone, OptionalMatrixType H2 = OptionalNone) const {
     std::vector<Matrix> Hs(2);
     const auto &keys = Factor::keys();
-    const Vector error = this->unwhitenedError(
+    const Vector error = unwhitenedError(
       {{keys[0], genericValue(a1)}, {keys[1], genericValue(a2)}}, 
       Hs);
     if (H1) *H1 = Hs[0];
diff --git a/gtsam/slam/BetweenFactor.h b/gtsam/slam/BetweenFactor.h
index a4ad013fc..897bf39e1 100644
--- a/gtsam/slam/BetweenFactor.h
+++ b/gtsam/slam/BetweenFactor.h
@@ -55,7 +55,8 @@ namespace gtsam {
     VALUE measured_; /** The measurement */
 
   public:
-	using Base::evaluateError;
+    // Provide access to the Matrix& version of evaluateError:
+    using Base::evaluateError;
 
     // shorthand for a smart pointer to a factor
     typedef typename boost::shared_ptr<BetweenFactor> shared_ptr;
diff --git a/gtsam/slam/BoundingConstraint.h b/gtsam/slam/BoundingConstraint.h
index 4837d6c54..b48a3e762 100644
--- a/gtsam/slam/BoundingConstraint.h
+++ b/gtsam/slam/BoundingConstraint.h
@@ -35,6 +35,7 @@ struct BoundingConstraint1: public NoiseModelFactorN<VALUE> {
   typedef NoiseModelFactorN<VALUE> Base;
   typedef boost::shared_ptr<BoundingConstraint1<VALUE> > shared_ptr;
 
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   double threshold_;
@@ -106,6 +107,7 @@ struct BoundingConstraint2: public NoiseModelFactorN<VALUE1, VALUE2> {
   typedef NoiseModelFactorN<VALUE1, VALUE2> Base;
   typedef boost::shared_ptr<BoundingConstraint2<VALUE1, VALUE2> > shared_ptr;
 
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   double threshold_;
diff --git a/gtsam/slam/EssentialMatrixConstraint.h b/gtsam/slam/EssentialMatrixConstraint.h
index a02dbb5f6..f76193f7c 100644
--- a/gtsam/slam/EssentialMatrixConstraint.h
+++ b/gtsam/slam/EssentialMatrixConstraint.h
@@ -37,6 +37,7 @@ private:
   EssentialMatrix measuredE_; /** The measurement is an essential matrix */
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   // shorthand for a smart pointer to a factor
diff --git a/gtsam/slam/EssentialMatrixFactor.h b/gtsam/slam/EssentialMatrixFactor.h
index 3e4a55dd6..43bc48b7d 100644
--- a/gtsam/slam/EssentialMatrixFactor.h
+++ b/gtsam/slam/EssentialMatrixFactor.h
@@ -38,6 +38,8 @@ class EssentialMatrixFactor : public NoiseModelFactorN<EssentialMatrix> {
   typedef EssentialMatrixFactor This;
 
  public:
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   /**
    *  Constructor
@@ -235,6 +237,7 @@ class EssentialMatrixFactor3 : public EssentialMatrixFactor2 {
   Rot3 cRb_;  ///< Rotation from body to camera frame
 
  public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   /**
    *  Constructor
@@ -336,6 +339,7 @@ class EssentialMatrixFactor4
   typedef Eigen::Matrix<double, 2, DimK> JacobianCalibration;
 
  public:
+   // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   /**
    *  Constructor
diff --git a/gtsam/slam/FrobeniusFactor.h b/gtsam/slam/FrobeniusFactor.h
index 07c79b32d..18181e091 100644
--- a/gtsam/slam/FrobeniusFactor.h
+++ b/gtsam/slam/FrobeniusFactor.h
@@ -54,7 +54,10 @@ class FrobeniusPrior : public NoiseModelFactorN<Rot> {
   Eigen::Matrix<double, Dim, 1> vecM_;  ///< vectorized matrix to approximate
 
  public:
+
+  // Provide access to the Matrix& version of evaluateError:
   using NoiseModelFactor1<Rot>::evaluateError;
+
   EIGEN_MAKE_ALIGNED_OPERATOR_NEW
 
   /// Constructor
@@ -79,6 +82,8 @@ class FrobeniusFactor : public NoiseModelFactorN<Rot, Rot> {
   enum { Dim = Rot::VectorN2::RowsAtCompileTime };
 
  public:
+
+  // Provide access to the Matrix& version of evaluateError:
   using NoiseModelFactor2<Rot, Rot>::evaluateError;
   /// Constructor
   FrobeniusFactor(Key j1, Key j2, const SharedNoiseModel& model = nullptr)
diff --git a/gtsam/slam/GeneralSFMFactor.h b/gtsam/slam/GeneralSFMFactor.h
index a1a78c5d3..78c7c8cd8 100644
--- a/gtsam/slam/GeneralSFMFactor.h
+++ b/gtsam/slam/GeneralSFMFactor.h
@@ -76,6 +76,9 @@ public:
   typedef GeneralSFMFactor<CAMERA, LANDMARK> This;///< typedef for this object
   typedef NoiseModelFactorN<CAMERA, LANDMARK> Base;///< typedef for the base class
 
+  // Provide access to the Matrix& version of evaluateError:
+  using Base::evaluateError;//
+
   // shorthand for a smart pointer to a factor
   typedef boost::shared_ptr<This> shared_ptr;
 
@@ -123,7 +126,7 @@ public:
 
   /** h(x)-z */
   Vector evaluateError(const CAMERA& camera, const LANDMARK& point,
-      OptionalMatrixType H1=OptionalNone, OptionalMatrixType H2=OptionalNone) const override {
+      OptionalMatrixType H1, OptionalMatrixType H2) const override {
     try {
       return camera.project2(point,H1,H2) - measured_;
     }
@@ -258,10 +261,7 @@ public:
 
   /** h(x)-z */
   Vector evaluateError(const Pose3& pose3, const Point3& point, const CALIBRATION &calib,
-      OptionalMatrixType H1=OptionalNone,
-      OptionalMatrixType H2=OptionalNone,
-      OptionalMatrixType H3=OptionalNone) const override
-  {
+      OptionalMatrixType H1, OptionalMatrixType H2, OptionalMatrixType H3) const override {
     try {
       Camera camera(pose3,calib);
       return camera.project(point, H1, H2, H3) - measured_;
diff --git a/gtsam/slam/OrientedPlane3Factor.h b/gtsam/slam/OrientedPlane3Factor.h
index a4d867e1c..4dac8b553 100644
--- a/gtsam/slam/OrientedPlane3Factor.h
+++ b/gtsam/slam/OrientedPlane3Factor.h
@@ -21,6 +21,7 @@ class GTSAM_EXPORT OrientedPlane3Factor: public NoiseModelFactorN<Pose3, Oriente
   typedef NoiseModelFactorN<Pose3, OrientedPlane3> Base;
 
  public:
+  // Provide access to the Matrix& version of evaluateError:
   using NoiseModelFactor2<Pose3, OrientedPlane3>::evaluateError;
   /// Constructor
   OrientedPlane3Factor() {
@@ -55,7 +56,10 @@ class GTSAM_EXPORT OrientedPlane3DirectionPrior : public NoiseModelFactorN<Orien
   typedef NoiseModelFactorN<OrientedPlane3> Base;
 
  public:
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
+
   typedef OrientedPlane3DirectionPrior This;
   /// Constructor
   OrientedPlane3DirectionPrior() {
diff --git a/gtsam/slam/PoseRotationPrior.h b/gtsam/slam/PoseRotationPrior.h
index 1d30ac859..58dfda8f9 100644
--- a/gtsam/slam/PoseRotationPrior.h
+++ b/gtsam/slam/PoseRotationPrior.h
@@ -25,6 +25,8 @@ public:
   typedef typename POSE::Translation Translation;
   typedef typename POSE::Rotation Rotation;
 
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   GTSAM_CONCEPT_POSE_TYPE(Pose)
diff --git a/gtsam/slam/PoseTranslationPrior.h b/gtsam/slam/PoseTranslationPrior.h
index 6f2982c28..fa21a7223 100644
--- a/gtsam/slam/PoseTranslationPrior.h
+++ b/gtsam/slam/PoseTranslationPrior.h
@@ -26,6 +26,8 @@ public:
   typedef typename POSE::Translation Translation;
   typedef typename POSE::Rotation Rotation;
   
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   GTSAM_CONCEPT_POSE_TYPE(Pose)
diff --git a/gtsam/slam/ProjectionFactor.h b/gtsam/slam/ProjectionFactor.h
index be8ad7cf0..28fd2628f 100644
--- a/gtsam/slam/ProjectionFactor.h
+++ b/gtsam/slam/ProjectionFactor.h
@@ -53,6 +53,8 @@ namespace gtsam {
 
     /// shorthand for base class type
     typedef NoiseModelFactor2<POSE, LANDMARK> Base;
+
+    // Provide access to the Matrix& version of evaluateError:
     using Base::evaluateError;
 
     /// shorthand for this class
diff --git a/gtsam/slam/ReferenceFrameFactor.h b/gtsam/slam/ReferenceFrameFactor.h
index ed7af6ad2..412233dee 100644
--- a/gtsam/slam/ReferenceFrameFactor.h
+++ b/gtsam/slam/ReferenceFrameFactor.h
@@ -62,6 +62,8 @@ protected:
 public:
   typedef NoiseModelFactorN<POINT, TRANSFORM, POINT> Base;
   typedef ReferenceFrameFactor<POINT, TRANSFORM> This;
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   typedef POINT Point;
diff --git a/gtsam/slam/RotateFactor.h b/gtsam/slam/RotateFactor.h
index 33336bf2a..1591cbe2f 100644
--- a/gtsam/slam/RotateFactor.h
+++ b/gtsam/slam/RotateFactor.h
@@ -28,6 +28,8 @@ class RotateFactor: public NoiseModelFactorN<Rot3> {
   typedef RotateFactor This;
 
 public:
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// Constructor
diff --git a/gtsam/slam/StereoFactor.h b/gtsam/slam/StereoFactor.h
index 0afe67b13..55fcfd61d 100644
--- a/gtsam/slam/StereoFactor.h
+++ b/gtsam/slam/StereoFactor.h
@@ -48,9 +48,10 @@ public:
   typedef boost::shared_ptr<GenericStereoFactor> shared_ptr;  ///< typedef for shared pointer to this object
   typedef POSE CamPose;                                       ///< typedef for Pose Lie Value type
 
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 	
-
   /**
    * Default constructor
    */
diff --git a/gtsam/slam/TriangulationFactor.h b/gtsam/slam/TriangulationFactor.h
index 98c972b9c..6fac062b9 100644
--- a/gtsam/slam/TriangulationFactor.h
+++ b/gtsam/slam/TriangulationFactor.h
@@ -61,6 +61,8 @@ public:
 
   /// shorthand for a smart pointer to a factor
   using shared_ptr = boost::shared_ptr<This>;
+
+  // Provide access to the Matrix& version of evaluateError:
   using NoiseModelFactor1<Point3>::evaluateError;
 
   /// Default constructor
diff --git a/gtsam_unstable/dynamics/FullIMUFactor.h b/gtsam_unstable/dynamics/FullIMUFactor.h
index 16409d866..9ba7f67fa 100644
--- a/gtsam_unstable/dynamics/FullIMUFactor.h
+++ b/gtsam_unstable/dynamics/FullIMUFactor.h
@@ -34,6 +34,8 @@ protected:
   double dt_; /// time between measurements
 
 public:
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /** Standard constructor */
diff --git a/gtsam_unstable/dynamics/Pendulum.h b/gtsam_unstable/dynamics/Pendulum.h
index 6d3126369..fb698764a 100644
--- a/gtsam_unstable/dynamics/Pendulum.h
+++ b/gtsam_unstable/dynamics/Pendulum.h
@@ -32,6 +32,8 @@ protected:
   double h_;  // time step
 
 public:
+
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   typedef boost::shared_ptr<PendulumFactor1> shared_ptr;
@@ -81,6 +83,7 @@ protected:
 
 public:
 
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   typedef boost::shared_ptr<PendulumFactor2 > shared_ptr;
@@ -131,6 +134,7 @@ protected:
 
 public:
 
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   typedef boost::shared_ptr<PendulumFactorPk > shared_ptr;
@@ -187,6 +191,7 @@ protected:
   double alpha_; //! in [0,1], define the mid-point between [q_k,q_{k+1}] for approximation. The sympletic rule above can be obtained as a special case when alpha = 0.
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   typedef boost::shared_ptr<PendulumFactorPk1 > shared_ptr;
diff --git a/gtsam_unstable/dynamics/SimpleHelicopter.h b/gtsam_unstable/dynamics/SimpleHelicopter.h
index 893d667c8..7938a3431 100644
--- a/gtsam_unstable/dynamics/SimpleHelicopter.h
+++ b/gtsam_unstable/dynamics/SimpleHelicopter.h
@@ -29,7 +29,9 @@ class Reconstruction : public NoiseModelFactorN<Pose3, Pose3, Vector6>  {
   double h_;  // time step
   typedef NoiseModelFactorN<Pose3, Pose3, Vector6> Base;
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
+
   Reconstruction(Key gKey1, Key gKey, Key xiKey, double h, double mu = 1000.0) :
     Base(noiseModel::Constrained::All(6, std::abs(mu)), gKey1, gKey,
         xiKey), h_(h) {
@@ -89,6 +91,7 @@ class DiscreteEulerPoincareHelicopter : public NoiseModelFactorN<Vector6, Vector
   typedef NoiseModelFactorN<Vector6, Vector6, Pose3> Base;
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   DiscreteEulerPoincareHelicopter(Key xiKey1, Key xiKey_1, Key gKey,
diff --git a/gtsam_unstable/dynamics/VelocityConstraint.h b/gtsam_unstable/dynamics/VelocityConstraint.h
index ece781f1c..91440fc92 100644
--- a/gtsam_unstable/dynamics/VelocityConstraint.h
+++ b/gtsam_unstable/dynamics/VelocityConstraint.h
@@ -35,6 +35,7 @@ typedef enum {
 class VelocityConstraint : public gtsam::NoiseModelFactorN<PoseRTV,PoseRTV> {
 public:
   typedef gtsam::NoiseModelFactor2<PoseRTV,PoseRTV> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
 protected:
diff --git a/gtsam_unstable/dynamics/VelocityConstraint3.h b/gtsam_unstable/dynamics/VelocityConstraint3.h
index 0b4f5b0b6..91905699c 100644
--- a/gtsam_unstable/dynamics/VelocityConstraint3.h
+++ b/gtsam_unstable/dynamics/VelocityConstraint3.h
@@ -23,6 +23,7 @@ protected:
 
 public:
 
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   typedef boost::shared_ptr<VelocityConstraint3 > shared_ptr;
 
diff --git a/gtsam_unstable/dynamics/tests/testSimpleHelicopter.cpp b/gtsam_unstable/dynamics/tests/testSimpleHelicopter.cpp
index 5cd72d377..a1ea046eb 100644
--- a/gtsam_unstable/dynamics/tests/testSimpleHelicopter.cpp
+++ b/gtsam_unstable/dynamics/tests/testSimpleHelicopter.cpp
@@ -58,10 +58,11 @@ TEST( Reconstruction, evaluateError) {
   EXPECT(
       assert_equal(Z_6x1, constraint.evaluateError(g2, g1, V1_g1, H1, H2, H3), tol));
 
-  std::function<Vector(const Pose3&, const Pose3&, const Vector6&)> f = [&constraint](const Pose3& a1, const Pose3& a2,
-                                                                                      const Vector6& a3) {
+  std::function<Vector(const Pose3&, const Pose3&, const Vector6&)> f = 
+    [&constraint](const Pose3& a1, const Pose3& a2, const Vector6& a3) {
     return constraint.evaluateError(a1, a2, a3);
   };
+
   Matrix numericalH1 = numericalDerivative31(f, g2, g1, V1_g1, 1e-5);
 
   Matrix numericalH2 = numericalDerivative32(f, g2, g1, V1_g1, 1e-5);
diff --git a/gtsam_unstable/slam/BetweenFactorEM.h b/gtsam_unstable/slam/BetweenFactorEM.h
index 510011ede..e19a4e28b 100644
--- a/gtsam_unstable/slam/BetweenFactorEM.h
+++ b/gtsam_unstable/slam/BetweenFactorEM.h
@@ -228,6 +228,8 @@ public:
     return err_wh_eq;
   }
 
+  // A function overload that takes a vector of matrices and passes it to the
+  // function above which uses a pointer to a vector instead.
   Vector whitenedError(const Values& x, std::vector<Matrix>& H) const {
 	  return whitenedError(x, &H);
   }
diff --git a/gtsam_unstable/slam/BiasedGPSFactor.h b/gtsam_unstable/slam/BiasedGPSFactor.h
index 0d4c2619d..e241310e9 100644
--- a/gtsam_unstable/slam/BiasedGPSFactor.h
+++ b/gtsam_unstable/slam/BiasedGPSFactor.h
@@ -37,7 +37,8 @@ namespace gtsam {
     Point3 measured_; /** The measurement */
 
   public:
-	using Base::evaluateError;
+    // Provide access to the Matrix& version of evaluateError:
+    using Base::evaluateError;
 
     // shorthand for a smart pointer to a factor
     typedef boost::shared_ptr<BiasedGPSFactor> shared_ptr;
diff --git a/gtsam_unstable/slam/EquivInertialNavFactor_GlobalVel.h b/gtsam_unstable/slam/EquivInertialNavFactor_GlobalVel.h
index a333ce439..529af878d 100644
--- a/gtsam_unstable/slam/EquivInertialNavFactor_GlobalVel.h
+++ b/gtsam_unstable/slam/EquivInertialNavFactor_GlobalVel.h
@@ -111,6 +111,7 @@ private:
 
 public:
 	
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   // shorthand for a smart pointer to a factor
diff --git a/gtsam_unstable/slam/EquivInertialNavFactor_GlobalVel_NoBias.h b/gtsam_unstable/slam/EquivInertialNavFactor_GlobalVel_NoBias.h
index 7fca72fb0..f3e27f7e5 100644
--- a/gtsam_unstable/slam/EquivInertialNavFactor_GlobalVel_NoBias.h
+++ b/gtsam_unstable/slam/EquivInertialNavFactor_GlobalVel_NoBias.h
@@ -109,7 +109,9 @@ private:
 
 public:
 
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
+
   // shorthand for a smart pointer to a factor
   typedef typename boost::shared_ptr<EquivInertialNavFactor_GlobalVel_NoBias> shared_ptr;
 
diff --git a/gtsam_unstable/slam/InertialNavFactor_GlobalVelocity.h b/gtsam_unstable/slam/InertialNavFactor_GlobalVelocity.h
index ad3c1287b..c5fbc9a32 100644
--- a/gtsam_unstable/slam/InertialNavFactor_GlobalVelocity.h
+++ b/gtsam_unstable/slam/InertialNavFactor_GlobalVelocity.h
@@ -95,6 +95,7 @@ private:
   boost::optional<POSE> body_P_sensor_; // The pose of the sensor in the body frame
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   // shorthand for a smart pointer to a factor
diff --git a/gtsam_unstable/slam/InvDepthFactor3.h b/gtsam_unstable/slam/InvDepthFactor3.h
index 98eadb9e2..8db48955b 100644
--- a/gtsam_unstable/slam/InvDepthFactor3.h
+++ b/gtsam_unstable/slam/InvDepthFactor3.h
@@ -35,6 +35,7 @@ public:
 
   /// shorthand for base class type
   typedef NoiseModelFactor3<POSE, LANDMARK, INVDEPTH> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// shorthand for this class
diff --git a/gtsam_unstable/slam/InvDepthFactorVariant1.h b/gtsam_unstable/slam/InvDepthFactorVariant1.h
index 39c7924d8..c8958f2f4 100644
--- a/gtsam_unstable/slam/InvDepthFactorVariant1.h
+++ b/gtsam_unstable/slam/InvDepthFactorVariant1.h
@@ -35,6 +35,7 @@ public:
 
   /// shorthand for base class type
   typedef NoiseModelFactor2<Pose3, Vector6> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// shorthand for this class
diff --git a/gtsam_unstable/slam/InvDepthFactorVariant2.h b/gtsam_unstable/slam/InvDepthFactorVariant2.h
index 51dfb02e9..967c9c9c5 100644
--- a/gtsam_unstable/slam/InvDepthFactorVariant2.h
+++ b/gtsam_unstable/slam/InvDepthFactorVariant2.h
@@ -37,6 +37,7 @@ public:
 
   /// shorthand for base class type
   typedef NoiseModelFactor2<Pose3, Vector3> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// shorthand for this class
diff --git a/gtsam_unstable/slam/InvDepthFactorVariant3.h b/gtsam_unstable/slam/InvDepthFactorVariant3.h
index 063128534..3685b48b9 100644
--- a/gtsam_unstable/slam/InvDepthFactorVariant3.h
+++ b/gtsam_unstable/slam/InvDepthFactorVariant3.h
@@ -35,6 +35,7 @@ public:
 
   /// shorthand for base class type
   typedef NoiseModelFactor2<Pose3, Vector3> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// shorthand for this class
diff --git a/gtsam_unstable/slam/LocalOrientedPlane3Factor.h b/gtsam_unstable/slam/LocalOrientedPlane3Factor.h
index 0bc456234..a8b42ed99 100644
--- a/gtsam_unstable/slam/LocalOrientedPlane3Factor.h
+++ b/gtsam_unstable/slam/LocalOrientedPlane3Factor.h
@@ -40,6 +40,7 @@ class GTSAM_UNSTABLE_EXPORT LocalOrientedPlane3Factor
   OrientedPlane3 measured_p_;
   typedef NoiseModelFactorN<Pose3, Pose3, OrientedPlane3> Base;
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   /// Constructor
   LocalOrientedPlane3Factor() {}
diff --git a/gtsam_unstable/slam/PartialPriorFactor.h b/gtsam_unstable/slam/PartialPriorFactor.h
index 3238bcdec..1bed15bba 100644
--- a/gtsam_unstable/slam/PartialPriorFactor.h
+++ b/gtsam_unstable/slam/PartialPriorFactor.h
@@ -61,6 +61,7 @@ namespace gtsam {
       : Base(model, key) {}
 
   public:
+    // Provide access to the Matrix& version of evaluateError:
     using Base::evaluateError;
 
     ~PartialPriorFactor() override {}
diff --git a/gtsam_unstable/slam/PoseBetweenFactor.h b/gtsam_unstable/slam/PoseBetweenFactor.h
index 9d5324c26..0d63af707 100644
--- a/gtsam_unstable/slam/PoseBetweenFactor.h
+++ b/gtsam_unstable/slam/PoseBetweenFactor.h
@@ -43,6 +43,7 @@ namespace gtsam {
     GTSAM_CONCEPT_TESTABLE_TYPE(POSE)
     GTSAM_CONCEPT_POSE_TYPE(POSE)
   public:
+    // Provide access to the Matrix& version of evaluateError:
     using Base::evaluateError;
 
     // shorthand for a smart pointer to a factor
diff --git a/gtsam_unstable/slam/PosePriorFactor.h b/gtsam_unstable/slam/PosePriorFactor.h
index f3bc3af57..5c73215a8 100644
--- a/gtsam_unstable/slam/PosePriorFactor.h
+++ b/gtsam_unstable/slam/PosePriorFactor.h
@@ -40,6 +40,7 @@ namespace gtsam {
     GTSAM_CONCEPT_TESTABLE_TYPE(POSE)
     GTSAM_CONCEPT_POSE_TYPE(POSE)
   public:
+    // Provide access to the Matrix& version of evaluateError:
     using Base::evaluateError;
 
     /// shorthand for a smart pointer to a factor
diff --git a/gtsam_unstable/slam/PoseToPointFactor.h b/gtsam_unstable/slam/PoseToPointFactor.h
index 164f8fafa..968c56407 100644
--- a/gtsam_unstable/slam/PoseToPointFactor.h
+++ b/gtsam_unstable/slam/PoseToPointFactor.h
@@ -29,7 +29,7 @@ class PoseToPointFactor : public NoiseModelFactorN<POSE, POINT> {
   POINT measured_; /** the point measurement in local coordinates */
 
  public:
-
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   // shorthand for a smart pointer to a factor
   typedef boost::shared_ptr<PoseToPointFactor> shared_ptr;
diff --git a/gtsam_unstable/slam/ProjectionFactorPPP.h b/gtsam_unstable/slam/ProjectionFactorPPP.h
index f19cefb1f..647cf566a 100644
--- a/gtsam_unstable/slam/ProjectionFactorPPP.h
+++ b/gtsam_unstable/slam/ProjectionFactorPPP.h
@@ -46,6 +46,7 @@ namespace gtsam {
 
     /// shorthand for base class type
     typedef NoiseModelFactor3<POSE, POSE, LANDMARK> Base;
+    // Provide access to the Matrix& version of evaluateError:
     using Base::evaluateError;
 
     /// shorthand for this class
diff --git a/gtsam_unstable/slam/ProjectionFactorPPPC.h b/gtsam_unstable/slam/ProjectionFactorPPPC.h
index 8068d1e27..304a54b97 100644
--- a/gtsam_unstable/slam/ProjectionFactorPPPC.h
+++ b/gtsam_unstable/slam/ProjectionFactorPPPC.h
@@ -45,6 +45,7 @@ class GTSAM_UNSTABLE_EXPORT ProjectionFactorPPPC
  public:
   /// shorthand for base class type
   typedef NoiseModelFactor4<POSE, POSE, LANDMARK, CALIBRATION> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// shorthand for this class
diff --git a/gtsam_unstable/slam/ProjectionFactorRollingShutter.h b/gtsam_unstable/slam/ProjectionFactorRollingShutter.h
index 4fc79863d..5ac0c9cf0 100644
--- a/gtsam_unstable/slam/ProjectionFactorRollingShutter.h
+++ b/gtsam_unstable/slam/ProjectionFactorRollingShutter.h
@@ -61,6 +61,7 @@ class GTSAM_UNSTABLE_EXPORT ProjectionFactorRollingShutter
  public:
   /// shorthand for base class type
   typedef NoiseModelFactor3<Pose3, Pose3, Point3> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// shorthand for this class
diff --git a/gtsam_unstable/slam/RelativeElevationFactor.h b/gtsam_unstable/slam/RelativeElevationFactor.h
index c617c80b7..9750313c2 100644
--- a/gtsam_unstable/slam/RelativeElevationFactor.h
+++ b/gtsam_unstable/slam/RelativeElevationFactor.h
@@ -34,6 +34,7 @@ private:
   typedef NoiseModelFactorN<Pose3, Point3> Base;
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   RelativeElevationFactor() : measured_(0.0) {} /* Default constructor */
diff --git a/gtsam_unstable/slam/SmartRangeFactor.h b/gtsam_unstable/slam/SmartRangeFactor.h
index f3a4440be..ef8d99d63 100644
--- a/gtsam_unstable/slam/SmartRangeFactor.h
+++ b/gtsam_unstable/slam/SmartRangeFactor.h
@@ -42,7 +42,9 @@ class SmartRangeFactor: public NoiseModelFactor {
   double variance_;  ///< variance on noise
 
  public:
+  // Provide access to the Matrix& version of unwhitenedError
   using NoiseModelFactor::unwhitenedError;
+
   /** Default constructor: don't use directly */
   SmartRangeFactor() {
   }
diff --git a/gtsam_unstable/slam/TSAMFactors.h b/gtsam_unstable/slam/TSAMFactors.h
index fe5e63848..caae63122 100644
--- a/gtsam_unstable/slam/TSAMFactors.h
+++ b/gtsam_unstable/slam/TSAMFactors.h
@@ -37,6 +37,7 @@ private:
   Point2 measured_; ///< the measurement
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// Constructor
@@ -66,6 +67,7 @@ private:
   Point2 measured_; ///< the measurement
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   /// Constructor
   DeltaFactorBase(Key b1, Key i, Key b2, Key j, const Point2& measured,
@@ -119,6 +121,7 @@ private:
   Pose2 measured_; ///< the measurement
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   /// Constructor
diff --git a/gtsam_unstable/slam/TransformBtwRobotsUnaryFactorEM.h b/gtsam_unstable/slam/TransformBtwRobotsUnaryFactorEM.h
index 591a50f13..7e0b699f6 100644
--- a/gtsam_unstable/slam/TransformBtwRobotsUnaryFactorEM.h
+++ b/gtsam_unstable/slam/TransformBtwRobotsUnaryFactorEM.h
@@ -245,9 +245,9 @@ namespace gtsam {
     }
     
     /* ************************************************************************* */
-	Vector whitenedError(const Values& x, std::vector<Matrix>& H) const {
-	  return whitenedError(x, &H);
-	}
+    Vector whitenedError(const Values& x, std::vector<Matrix>& H) const {
+      return whitenedError(x, &H);
+    }
 
     /* ************************************************************************* */
     Vector calcIndicatorProb(const Values& x) const {
diff --git a/tests/testExtendedKalmanFilter.cpp b/tests/testExtendedKalmanFilter.cpp
index dc6f08635..feeb4c43f 100644
--- a/tests/testExtendedKalmanFilter.cpp
+++ b/tests/testExtendedKalmanFilter.cpp
@@ -101,6 +101,7 @@ protected:
   Matrix Q_invsqrt_;
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
 
   NonlinearMotionModel(){}
@@ -246,6 +247,7 @@ protected:
   Matrix R_invsqrt_; /** The inv sqrt of the measurement error covariance */
 
 public:
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   NonlinearMeasurementModel(){}
 
diff --git a/tests/testNonlinearFactor.cpp b/tests/testNonlinearFactor.cpp
index ee0660866..cbfad704c 100644
--- a/tests/testNonlinearFactor.cpp
+++ b/tests/testNonlinearFactor.cpp
@@ -389,6 +389,7 @@ class TestFactor4 : public NoiseModelFactor4<double, double, double, double> {
 
  public:
   typedef NoiseModelFactor4<double, double, double, double> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   TestFactor4() : Base(noiseModel::Diagonal::Sigmas((Vector(1) << 2.0).finished()), X(1), X(2), X(3), X(4)) {}
   using Base::NoiseModelFactor4;  // inherit constructors
@@ -479,6 +480,7 @@ TEST(NonlinearFactor, NoiseModelFactor4) {
 class TestFactor5 : public NoiseModelFactor5<double, double, double, double, double> {
 public:
   typedef NoiseModelFactor5<double, double, double, double, double> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   TestFactor5() : Base(noiseModel::Diagonal::Sigmas((Vector(1) << 2.0).finished()), X(1), X(2), X(3), X(4), X(5)) {}
 
@@ -527,6 +529,7 @@ TEST(NonlinearFactor, NoiseModelFactor5) {
 class TestFactor6 : public NoiseModelFactor6<double, double, double, double, double, double> {
 public:
   typedef NoiseModelFactor6<double, double, double, double, double, double> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   TestFactor6() : Base(noiseModel::Diagonal::Sigmas((Vector(1) << 2.0).finished()), X(1), X(2), X(3), X(4), X(5), X(6)) {}
 
@@ -582,6 +585,7 @@ TEST(NonlinearFactor, NoiseModelFactor6) {
 class TestFactorN : public NoiseModelFactorN<double, double, double, double> {
 public:
   typedef NoiseModelFactorN<double, double, double, double> Base;
+  // Provide access to the Matrix& version of evaluateError:
   using Base::evaluateError;
   using Type1 = ValueType<1>;  // Test that we can use the ValueType<> template