CollectiveVariable.h

#pragma once

#include "types.h"
#include <vector>
#include <map>

// Forward declare.
namespace Json {
    class Value;
}

namespace SSAGES
{

    class CollectiveVariable
    {
    protected:
        std::vector<Vector3> grad_;

        Matrix3 boxgrad_;
        
        double val_;                

        std::array<double, 2> bounds_;      
    public:
        CollectiveVariable() : 
        grad_(0), boxgrad_(Matrix3::Zero()), val_(0), bounds_{{0,0}}
        {}

        virtual ~CollectiveVariable(){}


        virtual void Initialize(const class Snapshot&) {}


        virtual void Evaluate(const class Snapshot&) = 0;


        double GetValue() const
        {
            return val_;
        }


        virtual double GetMinimumImage(double /*location*/) const
        {
            return val_;
        }


        virtual double GetPeriodicValue(double location) const
        {
            return location;
        }


        const std::vector<Vector3>& GetGradient() const
        {
            return grad_;
        }

        /*
         * \return Gradient of CV with respect to box. 
         *
         * Returns the gradient of the CV with respect to the box.
         */
        const Matrix3& GetBoxGradient() const
        {
            return boxgrad_;
        }


        const std::array<double, 2>& GetBoundaries()
        {
            return bounds_;
        }


        virtual double GetDifference(double location) const
        {
            return val_ - location;
        }


        static CollectiveVariable* BuildCV(const Json::Value& json, const std::string& path);

    };
}