Interpolator.h

// -*- C++ -*-
//
// This file is part of LHAPDF
// Copyright (C) 2012-2024 The LHAPDF collaboration (see AUTHORS for details)
//
#pragma once
#ifndef LHAPDF_Interpolator_H
#define LHAPDF_Interpolator_H

#include "LHAPDF/Utils.h"
#include "LHAPDF/KnotArray.h"

namespace LHAPDF {


  // Forward declaration
  class GridPDF;


  class Interpolator {
  public:

    virtual ~Interpolator() { }



    void bind(const GridPDF* pdf) { _pdf = pdf; }

    void unbind() { _pdf = 0; }

    bool hasPDF() { return _pdf != 0; }

    const GridPDF& pdf() const { return *_pdf; }




    double interpolateXQ(int id, double x, double q) const {
      return interpolateXQ2(id, x, q*q);
    }

    double interpolateXQ2(int id, double x, double q2) const;

    void interpolateXQ2(double x, double q2, std::vector<double>& ret) const;



    std::string type() const {
      return _type;
    }

    void setType(std::string t) {
      _type = t;
    }


  protected:

    virtual double _interpolateXQ2(const KnotArray& grid, double x, size_t ix, double q2, size_t iq2, int id) const = 0;

    virtual void _interpolateXQ2(const KnotArray& grid, double x, size_t ix, double q2, size_t iq2, std::vector<double>& ret) const {
      ret.clear();
      ret.reserve(11);
      for (int pid = -6; pid < 6; pid++) {
        ret.push_back(_interpolateXQ2(grid, x, ix, q2, iq2, pid));
      }
    }


  private:
    const GridPDF* _pdf;
    std::string _type;
  };


}

#endif