fts/perturbation/Perturbation.h

#ifndef RP_PERTURBATION_H
#define RP_PERTURBATION_H
 
#include <util/param/ParamComposite.h>      // base class
 
// Forward declaration
namespace Util {  template <typename T> class DArray; }
 
namespace Pscf {
namespace Rp {
 
   using namespace Util;

   template <int D, class T>
   class Perturbation : public ParamComposite
   {
 
   public:
 
      // Protected constructor and destructor (see below).

      virtual void readParameters(std::istream& in);

      virtual void setup();

      virtual double hamiltonian(double unperturbedHamiltonian);

      virtual void incrementDc(DArray< typename T::RField >& dc);

      virtual void saveState();

      virtual void restoreState();

      virtual double df();

      typename T::Simulator const & simulator() const;

      typename T::System const & system() const;

      double lambda() const
      {  return lambda_; }

      void setLambda(double lambda);
 
   protected:

      Perturbation(typename T::Simulator& simulator);

      virtual ~Perturbation() = default;

      typename T::Simulator& simulator();

      typename T::System& system();

      double lambda_;
 
   private:

      typename T::Simulator* simulatorPtr_;

      typename T::System* systemPtr_;
 
   };
 
   // Inline methods
 
   // Return parent simulator by const reference.
   template <int D, class T>
   inline typename T::Simulator const & Perturbation<D,T>::simulator() const
   {
      assert(simulatorPtr_);
      return *simulatorPtr_;
   }
 
   // Return parent simulator by non-const reference.
   template <int D, class T>
   inline typename T::Simulator & Perturbation<D,T>::simulator()
   {
      assert(simulatorPtr_);
      return *simulatorPtr_;
   }
 
   // Return parent simulator by const reference.
   template <int D, class T>
   inline typename T::System const & Perturbation<D,T>::system() const
   {
      assert(systemPtr_);
      return *systemPtr_;
   }
 
   // Return parent simulator by non-const reference.
   template <int D, class T>
   inline typename T::System & Perturbation<D,T>::system()
   {
      assert(systemPtr_);
      return *systemPtr_;
   }
 
}
}
#endif