Bond Interaction Class Interface

Bond interaction classes are used in bond potential class templates to implement bond potential classes both the McMd and DdMd namespaces, in the templates McMd::BondPotentialImpl and DdMd::BondPotentialImpl. These templates call specific functions by name, and thus define an implicit interface that must be implemented by all bond interaction classes.

Here is a prototype class definition that shows the signatures for all of the required functions, for a hypothetical interaction class called Bond:

class Bond : public ParamComposite 
{

public:

   // Mutators

   // Set nBondType value.
   // 
   // \param nBondType number of bond types.
   //
   void setNBondType(int nBondType);

   // Read parameters for this bond interaction function.
   //
   // \pre nBondType must have been set, by calling setNBondType().
   //
   // \param in  input stream 
   //
   virtual void readParameters(std::istream &in);

   // Load internal state from an archive.
   //
   // \param ar input/loading archive
   //
   virtual void loadParameters(Serializable::IArchive &ar);

   // Save internal state to an archive.
   //
   // \param ar output/saving archive
   //
   virtual void save(Serializable::OArchive &ar);

   // Modify a parameter, identified by a name string.
   //
   // \param name    parameter name
   // \param typeId  integer bond type id
   // \param value  new value of parameter
   //
   void set(std::string name, int typeId, double value);

   // Accessors

   // Return interaction energy for a single bond of particles. 
   //
   // \param rsq     square of distance between particles
   // \param typeId  integer bond type id
   // \return    bond interaction energy
   //
   double energy(double rsq, int typeId) const;

   // Returns ratio of scalar bond interaction force to bond separation.
   //
   // Multiply this quantity by the components of the separation vector
   // to obtain the force vector. A positive value for the return value
   // represents a repulsive force between a bond of particles.
   //
   // \param rsq    square of distance between particles
   // \param typeId integer bond type id
   // \return    force divided by distance 
   //
   double forceOverR(double rsq, int i) const;

   // Get a parameter value, identified by a string.
   //
   // \param name   parameter name
   // \param typeId integer bond type id
   //
   double get(std::string name, int typeId) const;

};