PointSymmetry.h

#ifndef UTIL_POINT_SYMMETRY_H
#define UTIL_POINT_SYMMETRY_H

#include <util/space/Dimension.h>
#include <util/containers/FMatrix.h>

#include <iostream>

namespace Util {

   class IntVector;

   class PointSymmetry 
   {

   public:

      typedef FMatrix<int, Dimension, Dimension> Matrix;

      PointSymmetry();

      PointSymmetry(const PointSymmetry& other);

      PointSymmetry& operator = (const PointSymmetry& other);

      PointSymmetry inverse() const;

      int& R(int i, int j);
 
      int  R(int i, int j) const;

      // Static method

      static const PointSymmetry& identity();
 
   private:

      Matrix R_;

      static PointSymmetry identity_;

      static bool hasIdentity_;

      static void makeIdentity();

   // friends:

      friend bool operator==(const PointSymmetry& A, const PointSymmetry& B);

      friend bool operator!=(const PointSymmetry& A, const PointSymmetry& B);

      friend PointSymmetry 
      operator * (const PointSymmetry& A, const PointSymmetry& B);

      friend IntVector operator * (const PointSymmetry& S, const IntVector& V);

      friend IntVector operator * (const IntVector& V, const PointSymmetry& S);

      friend std::ostream& operator << (std::ostream& out, const PointSymmetry& A);

   };

   // Friend function declarations

   bool operator == (const PointSymmetry& A, const PointSymmetry& B);

   bool operator != (const PointSymmetry& A, const PointSymmetry& B);

   PointSymmetry operator * (const PointSymmetry& A, const PointSymmetry& B);

   IntVector operator * (const PointSymmetry& S, const IntVector& V);

   IntVector operator * (const IntVector& V, const PointSymmetry& S);

   std::ostream& operator << (std::ostream& out, const PointSymmetry& A);

   // Inline method definitions

   inline bool operator != (const PointSymmetry& A, const PointSymmetry& B)
   {  return !(A == B); }

   /*
   * Return an element of the matrix by reference.
   */
   inline int& PointSymmetry::R(int i, int j)
   {  return R_(i, j); }
 
   /*
   * Return an element of the matrix by value
   */
   inline int  PointSymmetry::R(int i, int j) const
   {  return R_(i, j); }

   /*
   * Return identity element.
   */
   inline const PointSymmetry& PointSymmetry::identity()
   {
      if (!hasIdentity_) makeIdentity();
      return identity_;
   }
 
}
#endif