Change all occurances of unnamed enum (deprecated in C++20) to `constexpr`

GTSAM-Concepts.md

@@ -22,7 +22,7 @@ In GTSAM, all properties and operations needed to use a type must be defined thr
 In detail, we ask that the following items are defined in the traits object (although, not all are needed for optimization):
 
 * values:
-   * `enum { dimension = D};`, an enum that indicates the dimensionality *n* of the manifold. In Eigen-fashion, we also support manifolds whose dimensionality is only defined at runtime, by specifying the value -1.
+   * `inline constexpr static auto dimension = D;`, a constexpr that indicates the dimensionality *n* of the manifold. In Eigen-fashion, we also support manifolds whose dimensionality is only defined at runtime, by specifying the value -1.
 * types:
     * `TangentVector`, type that lives in tangent space. This will almost always be an `Eigen::Matrix<double,n,1>`.
     * `ChartJacobian`, a typedef for `OptionalJacobian<dimension, dimension>`.

gtsam/base/GenericValue.h

@@ -184,9 +184,8 @@ public:
 	}
 #endif
 
-
   // Alignment, see https://eigen.tuxfamily.org/dox/group__TopicStructHavingEigenMembers.html
-  enum { NeedsToAlign = (sizeof(T) % 16) == 0 };
+  constexpr static const bool NeedsToAlign = (sizeof(T) % 16) == 0;
 public:
   GTSAM_MAKE_ALIGNED_OPERATOR_NEW_IF(NeedsToAlign)
 };

gtsam/base/Lie.h

@@ -36,7 +36,7 @@ namespace gtsam {
 template <class Class, int N>
 struct LieGroup {
 
-  enum { dimension = N };
+  inline constexpr static auto dimension = N;
   typedef OptionalJacobian<N, N> ChartJacobian;
   typedef Eigen::Matrix<double, N, N> Jacobian;
   typedef Eigen::Matrix<double, N, 1> TangentVector;
@@ -183,7 +183,7 @@ struct LieGroupTraits: GetDimensionImpl<Class, Class::dimension> {
   /// @name Manifold
   /// @{
   typedef Class ManifoldType;
-  enum { dimension = Class::dimension };
+  inline constexpr static auto dimension = Class::dimension;
   typedef Eigen::Matrix<double, dimension, 1> TangentVector;
   typedef OptionalJacobian<dimension, dimension> ChartJacobian;
 

gtsam/base/Manifold.h

@@ -55,7 +55,7 @@ namespace internal {
 template<class Class>
 struct HasManifoldPrereqs {
 
-  enum { dim = Class::dimension };
+  inline constexpr static auto dim = Class::dimension;
 
   Class p, q;
   Eigen::Matrix<double, dim, 1> v;
@@ -95,7 +95,7 @@ struct ManifoldTraits: GetDimensionImpl<Class, Class::dimension> {
   GTSAM_CONCEPT_ASSERT(HasManifoldPrereqs<Class>);
 
   // Dimension of the manifold
-  enum { dimension = Class::dimension };
+  inline constexpr static auto dimension = Class::dimension;
 
   // Typedefs required by all manifold types.
   typedef Class ManifoldType;

gtsam/base/Matrix.h

@@ -479,7 +479,7 @@ struct MultiplyWithInverse {
  */
 template <typename T, int N>
 struct MultiplyWithInverseFunction {
-  enum { M = traits<T>::dimension };
+  inline constexpr static auto M = traits<T>::dimension;
   typedef Eigen::Matrix<double, N, 1> VectorN;
   typedef Eigen::Matrix<double, N, N> MatrixN;
 

gtsam/base/ProductLieGroup.h

@@ -67,9 +67,9 @@ public:
 
   /// @name Manifold
   /// @{
-  enum {dimension = dimension1 + dimension2};
-  inline static size_t Dim() {return dimension;}
-  inline size_t dim() const {return dimension;}
+  inline constexpr static auto dimension = dimension1 + dimension2;
+  inline static size_t Dim() { return dimension; }
+  inline size_t dim() const { return dimension; }
 
   typedef Eigen::Matrix<double, dimension, 1> TangentVector;
   typedef OptionalJacobian<dimension, dimension> ChartJacobian;

gtsam/base/VectorSpace.h

@@ -163,7 +163,7 @@ struct VectorSpaceImpl<Class,Eigen::Dynamic> {
 template<class Class>
 struct HasVectorSpacePrereqs {
 
-  enum { dim = Class::dimension };
+  inline constexpr static auto dim = Class::dimension;
 
   Class p, q;
   Vector v;
@@ -197,7 +197,7 @@ GTSAM_CONCEPT_ASSERT(HasVectorSpacePrereqs<Class>);
 
   /// @name Manifold
   /// @{
-  enum { dimension = Class::dimension};
+  inline constexpr static auto dimension = Class::dimension;
   typedef Class ManifoldType;
   /// @}
 };
@@ -232,7 +232,7 @@ struct ScalarTraits : VectorSpaceImpl<Scalar, 1> {
   /// @name Manifold
   /// @{
   typedef Scalar ManifoldType;
-  enum { dimension = 1 };
+  inline constexpr static auto dimension = 1;
   typedef Eigen::Matrix<double, 1, 1> TangentVector;
   typedef OptionalJacobian<1, 1> ChartJacobian;
 
@@ -305,7 +305,7 @@ struct traits<Eigen::Matrix<double, M, N, Options, MaxRows, MaxCols> > :
 
   /// @name Manifold
   /// @{
-  enum { dimension = M*N};
+  inline constexpr static auto dimension = M * N;
   typedef Fixed ManifoldType;
   typedef Eigen::Matrix<double, dimension, 1> TangentVector;
   typedef Eigen::Matrix<double, dimension, dimension> Jacobian;
@@ -377,7 +377,7 @@ struct DynamicTraits {
 
   /// @name Manifold
   /// @{
-  enum { dimension = Eigen::Dynamic };
+  inline constexpr static auto dimension = Eigen::Dynamic;
   typedef Eigen::VectorXd TangentVector;
   typedef Eigen::MatrixXd Jacobian;
   typedef OptionalJacobian<dimension, dimension> ChartJacobian;

gtsam/basis/Basis.h

@@ -291,7 +291,7 @@ class Basis {
    */
   template <class T>
   class ManifoldEvaluationFunctor : public VectorEvaluationFunctor {
-    enum { M = traits<T>::dimension };
+    inline constexpr static auto M = traits<T>::dimension;
     using Base = VectorEvaluationFunctor;
 
    public:

gtsam/geometry/BearingRange.h

@@ -162,9 +162,7 @@ private:
   /// @}
 
   // Alignment, see https://eigen.tuxfamily.org/dox/group__TopicStructHavingEigenMembers.html
-  enum {
-    NeedsToAlign = (sizeof(B) % 16) == 0 || (sizeof(R) % 16) == 0
-  };
+  inline constexpr static auto NeedsToAlign = (sizeof(B) % 16) == 0 || (sizeof(R) % 16) == 0;
 public:
   GTSAM_MAKE_ALIGNED_OPERATOR_NEW_IF(NeedsToAlign)
 };

gtsam/geometry/Cal3.h

@@ -73,7 +73,7 @@ class GTSAM_EXPORT Cal3 {
   double u0_ = 0.0f, v0_ = 0.0f;  ///< principal point
 
  public:
-  enum { dimension = 5 };
+  inline constexpr static auto dimension = 5;
   ///< shared pointer to calibration object
   using shared_ptr = std::shared_ptr<Cal3>;
 

gtsam/geometry/Cal3Bundler.h

@@ -37,7 +37,7 @@ class GTSAM_EXPORT Cal3Bundler : public Cal3f {
   // Note: u0 and v0 are constants and not optimized.
 
  public:
-  enum { dimension = 3 };
+  inline constexpr static auto dimension = 3;
   using shared_ptr = std::shared_ptr<Cal3Bundler>;
 
   /// @name Constructors

gtsam/geometry/Cal3DS2.h

@@ -36,7 +36,7 @@ class GTSAM_EXPORT Cal3DS2 : public Cal3DS2_Base {
   using Base = Cal3DS2_Base;
 
  public:
-  enum { dimension = 9 };
+  inline constexpr static auto dimension = 9;
 
   ///< shared pointer to stereo calibration object
   using shared_ptr = std::shared_ptr<Cal3DS2>;

gtsam/geometry/Cal3DS2_Base.h

@@ -46,7 +46,7 @@ class GTSAM_EXPORT Cal3DS2_Base : public Cal3 {
   double tol_ = 1e-5;             ///< tolerance value when calibrating
 
  public:
-  enum { dimension = 9 };
+  inline constexpr static auto dimension = 9;
 
   ///< shared pointer to stereo calibration object
   using shared_ptr = std::shared_ptr<Cal3DS2_Base>;

gtsam/geometry/Cal3Fisheye.h

@@ -55,7 +55,7 @@ class GTSAM_EXPORT Cal3Fisheye : public Cal3 {
   double tol_ = 1e-5;             ///< tolerance value when calibrating
 
  public:
-  enum { dimension = 9 };
+  inline constexpr static auto dimension = 9;
   ///< shared pointer to fisheye calibration object
   using shared_ptr = std::shared_ptr<Cal3Fisheye>;
 

gtsam/geometry/Cal3Unified.h

@@ -50,7 +50,7 @@ class GTSAM_EXPORT Cal3Unified : public Cal3DS2_Base {
   double xi_ = 0.0f;  ///< mirror parameter
 
  public:
-  enum { dimension = 10 };
+  inline constexpr static auto dimension = 10;
 
   ///< shared pointer to stereo calibration object
   using shared_ptr = std::shared_ptr<Cal3Unified>;

gtsam/geometry/Cal3_S2.h

@@ -33,7 +33,7 @@ namespace gtsam {
  */
 class GTSAM_EXPORT Cal3_S2 : public Cal3 {
  public:
-  enum { dimension = 5 };
+  inline constexpr static auto dimension = 5;
 
   ///< shared pointer to calibration object
   using shared_ptr = std::shared_ptr<Cal3_S2>;

gtsam/geometry/Cal3_S2Stereo.h

@@ -32,7 +32,7 @@ class GTSAM_EXPORT Cal3_S2Stereo : public Cal3_S2 {
   double b_ = 1.0f;  ///< Stereo baseline.
 
  public:
-  enum { dimension = 6 };
+  inline constexpr static auto dimension = 6;
 
   ///< shared pointer to stereo calibration object
   using shared_ptr = std::shared_ptr<Cal3_S2Stereo>;

gtsam/geometry/Cal3f.h

@@ -34,7 +34,7 @@ namespace gtsam {
  */
 class GTSAM_EXPORT Cal3f : public Cal3 {
  public:
-  enum { dimension = 1 };
+  inline constexpr static auto dimension = 1;
   using shared_ptr = std::shared_ptr<Cal3f>;
 
   /// @name Constructors

gtsam/geometry/CalibratedCamera.h

@@ -252,9 +252,7 @@ class GTSAM_EXPORT CalibratedCamera: public PinholeBase {
 
 public:
 
-  enum {
-    dimension = 6
-  };
+  inline constexpr static auto dimension = 6;
 
   /// @name Standard Constructors
   /// @{

gtsam/geometry/EssentialMatrix.h

@@ -82,7 +82,7 @@ class EssentialMatrix {
 
   /// @name Manifold
   /// @{
-  enum { dimension = 5 };
+  inline constexpr static auto dimension = 5;
   inline static size_t Dim() { return dimension;}
   inline size_t dim() const { return dimension;}
 

gtsam/geometry/FundamentalMatrix.h

@@ -102,7 +102,7 @@ class GTSAM_EXPORT FundamentalMatrix {
 
   /// @name Manifold
   /// @{
-  enum { dimension = 7 };  // 3 for U, 1 for s, 3 for V
+  inline constexpr static auto dimension = 7;  // 3 for U, 1 for s, 3 for V
   inline static size_t Dim() { return dimension; }
   inline size_t dim() const { return dimension; }
 
@@ -179,7 +179,7 @@ class GTSAM_EXPORT SimpleFundamentalMatrix {
 
   /// @name Manifold
   /// @{
-  enum { dimension = 7 };  // 5 for E, 1 for fa, 1 for fb
+  inline constexpr static auto dimension = 7;  // 5 for E, 1 for fa, 1 for fb
   inline static size_t Dim() { return dimension; }
   inline size_t dim() const { return dimension; }
 

gtsam/geometry/Line3.h

@@ -47,7 +47,7 @@ class GTSAM_EXPORT Line3 {
   double a_, b_;  // Intersection of line with the world x-y plane rotated by R_
   // Also the closest point on line to origin
  public:
-  enum { dimension = 4 };
+  inline constexpr static auto dimension = 4;
 
   /** Default constructor is the Z axis **/
   Line3() :

gtsam/geometry/OrientedPlane3.h

@@ -39,9 +39,7 @@ private:
   double d_;    ///< The perpendicular distance to this plane
 
 public:
-  enum {
-    dimension = 3
-  };
+  inline constexpr static auto dimension = 3;
 
   /// @name Constructors
   /// @{

gtsam/geometry/PinholeCamera.h

@@ -51,9 +51,7 @@ private:
 
 public:
 
-  enum {
-    dimension = 6 + DimK
-  }; ///< Dimension depends on calibration
+  inline constexpr static auto dimension = 6 + DimK; ///< Dimension depends on calibration
 
   /// @name Standard Constructors
   /// @{

gtsam/geometry/PinholePose.h

@@ -245,9 +245,7 @@ private:
 
 public:
 
-  enum {
-    dimension = 6
-  }; ///< There are 6 DOF to optimize for
+  inline constexpr static auto dimension = 6; ///< There are 6 DOF to optimize for
 
   /// @name Standard Constructors
   /// @{

gtsam/geometry/Quaternion.h

@@ -45,9 +45,7 @@ struct traits<QUATERNION_TYPE> {
   /// @}
   /// @name Basic manifold traits
   /// @{
-  enum {
-    dimension = 3
-  };
+  inline constexpr static auto dimension = 3;
   typedef OptionalJacobian<3, 3> ChartJacobian;
   typedef Eigen::Matrix<_Scalar, 3, 1, _Options, 3, 1> TangentVector;
 

gtsam/geometry/SOn.h

@@ -54,7 +54,7 @@ constexpr int NSquaredSO(int N) { return (N < 0) ? Eigen::Dynamic : N * N; }
 template <int N>
 class SO : public LieGroup<SO<N>, internal::DimensionSO(N)> {
  public:
-  enum { dimension = internal::DimensionSO(N) };
+  inline constexpr static auto dimension = internal::DimensionSO(N);
   using MatrixNN = Eigen::Matrix<double, N, N>;
   using VectorN2 = Eigen::Matrix<double, internal::NSquaredSO(N), 1>;
   using MatrixDD = Eigen::Matrix<double, dimension, dimension>;

gtsam/geometry/SphericalCamera.h

@@ -41,7 +41,7 @@ namespace gtsam {
  */
 class GTSAM_EXPORT EmptyCal {
  public:
-  enum { dimension = 0 };
+  inline constexpr static auto dimension = 0;
   EmptyCal() {}
   virtual ~EmptyCal() = default;
   using shared_ptr = std::shared_ptr<EmptyCal>;
@@ -73,7 +73,7 @@ class GTSAM_EXPORT EmptyCal {
  */
 class GTSAM_EXPORT SphericalCamera {
  public:
-  enum { dimension = 6 };
+  inline constexpr static auto dimension = 6;
 
   using Measurement = Unit3;
   using MeasurementVector = std::vector<Unit3>;

gtsam/geometry/StereoCamera.h

@@ -61,9 +61,7 @@ private:
 
 public:
 
-  enum {
-    dimension = 6
-  };
+  inline constexpr static auto dimension = 6;
 
   /// @name Standard Constructors
   /// @{

gtsam/geometry/StereoPoint2.h

@@ -37,7 +37,7 @@ private:
   double uL_, uR_, v_;
 
 public:
-  enum { dimension = 3 };
+  inline constexpr static auto dimension = 3;
   /// @name Standard Constructors
   /// @{
 

gtsam/geometry/Unit3.h

@@ -53,9 +53,7 @@ private:
 
 public:
 
-  enum {
-    dimension = 2
-  };
+  inline constexpr static auto dimension = 2;
 
   /// @name Constructors
   /// @{

gtsam/navigation/NavState.h

@@ -42,9 +42,7 @@ private:
 
 public:
 
-  enum {
-    dimension = 9
-  };
+  inline constexpr static auto dimension = 9;
 
   typedef std::pair<Point3, Velocity3> PositionAndVelocity;
 

gtsam/nonlinear/ExpressionFactor.h

@@ -224,7 +224,7 @@ private:
 #endif
 
  // Alignment, see https://eigen.tuxfamily.org/dox/group__TopicStructHavingEigenMembers.html
- enum { NeedsToAlign = (sizeof(T) % 16) == 0 };
+ inline constexpr static auto NeedsToAlign = (sizeof(T) % 16) == 0;
  public:
   GTSAM_MAKE_ALIGNED_OPERATOR_NEW_IF(NeedsToAlign)
 };

gtsam/nonlinear/NonlinearFactor.h

@@ -434,7 +434,7 @@ class NoiseModelFactorN
       public detail::NoiseModelFactorAliases<ValueTypes...> {
  public:
   /// N is the number of variables (N-way factor)
-  enum { N = sizeof...(ValueTypes) };
+  inline constexpr static auto N = sizeof...(ValueTypes);
 
   using NoiseModelFactor::unwhitenedError;
 

gtsam/nonlinear/PriorFactor.h

@@ -118,7 +118,7 @@ namespace gtsam {
 #endif
 
   // Alignment, see https://eigen.tuxfamily.org/dox/group__TopicStructHavingEigenMembers.html
-  enum { NeedsToAlign = (sizeof(T) % 16) == 0 };
+  inline constexpr static auto NeedsToAlign = (sizeof(T) % 16) == 0;
   public:
   GTSAM_MAKE_ALIGNED_OPERATOR_NEW_IF(NeedsToAlign)
   };

gtsam/nonlinear/tests/testExpression.cpp

@@ -115,7 +115,7 @@ TEST(Expression, Unary3) {
 // Simple test class that implements the `VectorSpace` protocol.
 class Class : public Point3 {
  public:
-  enum {dimension = 3};
+  inline constexpr static auto dimension = 3;
   using Point3::Point3;
   const Vector3& vector() const { return *this; }
   inline static Class Identity() { return Class(0,0,0); }

gtsam/nonlinear/tests/testValues.cpp

@@ -54,7 +54,7 @@ int TestValueData::DestructorCount = 0;
 class TestValue {
   TestValueData data_;
 public:
-  enum {dimension = 0};
+  inline constexpr static auto dimension = 0;
   void print(const std::string& str = "") const {}
   bool equals(const TestValue& other, double tol = 1e-9) const { return true; }
   size_t dim() const { return 0; }

gtsam/slam/BetweenFactor.h

@@ -148,7 +148,7 @@ namespace gtsam {
 #endif
 
     // Alignment, see https://eigen.tuxfamily.org/dox/group__TopicStructHavingEigenMembers.html
-	  enum { NeedsToAlign = (sizeof(VALUE) % 16) == 0 };
+    inline constexpr static auto NeedsToAlign = (sizeof(VALUE) % 16) == 0;
   public:
     GTSAM_MAKE_ALIGNED_OPERATOR_NEW_IF(NeedsToAlign)
   }; // \class BetweenFactor

gtsam/slam/FrobeniusFactor.h

@@ -49,7 +49,7 @@ ConvertNoiseModel(const SharedNoiseModel &model, size_t n,
  */
 template <class Rot>
 class FrobeniusPrior : public NoiseModelFactorN<Rot> {
-  enum { Dim = Rot::VectorN2::RowsAtCompileTime };
+  inline constexpr static auto Dim = Rot::VectorN2::RowsAtCompileTime;
   using MatrixNN = typename Rot::MatrixNN;
   Eigen::Matrix<double, Dim, 1> vecM_;  ///< vectorized matrix to approximate
 
@@ -79,7 +79,7 @@ class FrobeniusPrior : public NoiseModelFactorN<Rot> {
  */
 template <class Rot>
 class FrobeniusFactor : public NoiseModelFactorN<Rot, Rot> {
-  enum { Dim = Rot::VectorN2::RowsAtCompileTime };
+  inline constexpr static auto Dim = Rot::VectorN2::RowsAtCompileTime;
 
  public:
 
@@ -111,7 +111,7 @@ class FrobeniusBetweenFactor : public NoiseModelFactorN<Rot, Rot> {
   Rot R12_;  ///< measured rotation between R1 and R2
   Eigen::Matrix<double, Rot::dimension, Rot::dimension>
       R2hat_H_R1_;  ///< fixed derivative of R2hat wrpt R1
-  enum { Dim = Rot::VectorN2::RowsAtCompileTime };
+  inline constexpr static auto Dim = Rot::VectorN2::RowsAtCompileTime;
 
  public:
 

gtsam/slam/KarcherMeanFactor.h

@@ -45,7 +45,7 @@ template <class T> T FindKarcherMean(std::initializer_list<T> &&rotations);
  * */
 template <class T> class KarcherMeanFactor : public NonlinearFactor {
   // Compile time dimension: can be -1
-  enum { D = traits<T>::dimension };
+  inline constexpr static auto D = traits<T>::dimension;
 
   // Runtime dimension: always >=0
   size_t d_;

gtsam_unstable/geometry/Event.h

@@ -39,7 +39,7 @@ class GTSAM_UNSTABLE_EXPORT Event {
   Point3 location_;  ///< Location at time event was generated
 
  public:
-  enum { dimension = 4 };
+  inline constexpr static auto dimension = 4;
 
   /// Default Constructor
   Event() : time_(0), location_(0, 0, 0) {}