PairPotentials/Base.hpp

#ifndef OPENMPCD_PAIRPOTENTIALS_BASE_HPP
#define OPENMPCD_PAIRPOTENTIALS_BASE_HPP
 
#include <OpenMPCD/CUDA/Macros.hpp>
#include <OpenMPCD/Types.hpp>
#include <OpenMPCD/Vector3D.hpp>
 
namespace OpenMPCD
{
 
/**
 * Namespace hosting various pair potentials, i.e. potentials depending on the
 * distance between pairs of particles.
 */
namespace PairPotentials
{
 
/**
 * Abstract base class for pair potentials.
 *
 * @tparam T The numeric base type.
 */
template<typename T = FP>
class Base
{
public:
    /**
     * The destructor.
     */
    OPENMPCD_CUDA_HOST_AND_DEVICE
    virtual ~Base()
    {
    }
 
    /**
     * Returns the force vector of the interaction for a given position vector.
     *
     * This function returns the directional derivative
     * \f[ - \nabla_R V \left( \vec{R} \right) \f]
     * where \f$ \vec{R} \f$ is the `Rvec` parameter, \f$ V \f$ is the potential
     * as given by the `potential` function, and \f$ \nabla_R V \f$ is the
     * gradient of \f$ V \f$ with respect to \f$ \vec{R} \f$.
     *
     * @param[in]   Rvec    The relative position vector.
     */
    OPENMPCD_CUDA_HOST_AND_DEVICE
    virtual Vector3D<T> force(const Vector3D<T>& Rvec) const = 0;
 
    /**
     * Returns the potential of the interaction for a given position vector.
     * @param[in]   Rvec    The relative position vector.
     */
    OPENMPCD_CUDA_HOST_AND_DEVICE
    virtual T potential(const Vector3D<T>& Rvec) const = 0;
 
    /**
     * Returns the force exerted on the particle at `r1` due to the particle at
     * `r2`.
     *
     * @param[in] r1 The position of the first particle.
     * @param[in] r2 The position of the second particle.
     */
    OPENMPCD_CUDA_HOST_AND_DEVICE
    const Vector3D<T>
    forceOnR1DueToR2(const Vector3D<T>& r1, const Vector3D<T>& r2) const
    {
        return force(r1 - r2);
    }
 
}; //class Base
 
} //namespace PairPotentials
} //namespace OpenMPCD
#endif //OPENMPCD_PAIRPOTENTIALS_BASE_HPP