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//
// G4Integrator
//
// Class description:
//
// Template class collecting integrator methods for generic funtions.

// Author: V.Grichine, 04.09.1999 - First implementation based on
//         G4SimpleIntegration class with H.P.Wellisch, G.Cosmo, and
//         E.TCherniaev advises
// --------------------------------------------------------------------
#ifndef G4INTEGRATOR_HH
#define G4INTEGRATOR_HH 1

#include "G4Types.hh"
#include <CLHEP/Units/PhysicalConstants.h>
#include <cmath>

template <class T, class F>
class G4Integrator
{
 public:
  G4Integrator() { ; }
  ~G4Integrator() { ; }

  G4double Simpson(T& typeT, F f, G4double a, G4double b, G4int n);
  G4double Simpson(T* ptrT, F f, G4double a, G4double b, G4int n);
  G4double Simpson(G4double (*f)(G4double), G4double a, G4double b, G4int n);
  // Simpson integration method

  G4double AdaptiveGauss(T& typeT, F f, G4double a, G4double b, G4double e);
  G4double AdaptiveGauss(T* ptrT, F f, G4double a, G4double b, G4double e);
  G4double AdaptiveGauss(G4double (*f)(G4double), G4double a, G4double b,
                         G4double e);
  // Adaptive Gauss method

  // Integration methods involving orthogohol polynomials

  G4double Legendre(T& typeT, F f, G4double a, G4double b, G4int n);
  G4double Legendre(T* ptrT, F f, G4double a, G4double b, G4int n);
  G4double Legendre(G4double (*f)(G4double), G4double a, G4double b, G4int n);
  //
  // Methods involving Legendre polynomials

  G4double Legendre10(T& typeT, F f, G4double a, G4double b);
  G4double Legendre10(T* ptrT, F f, G4double a, G4double b);
  G4double Legendre10(G4double (*f)(G4double), G4double a, G4double b);
  //
  // Legendre10 is very fast and accurate enough

  G4double Legendre96(T& typeT, F f, G4double a, G4double b);
  G4double Legendre96(T* ptrT, F f, G4double a, G4double b);
  G4double Legendre96(G4double (*f)(G4double), G4double a, G4double b);
  //
  // Legendre96 is very accurate and fast enough

  G4double Chebyshev(T& typeT, F f, G4double a, G4double b, G4int n);
  G4double Chebyshev(T* ptrT, F f, G4double a, G4double b, G4int n);
  G4double Chebyshev(G4double (*f)(G4double), G4double a, G4double b, G4int n);
  //
  // Methods involving Chebyshev  polynomials

  G4double Laguerre(T& typeT, F f, G4double alpha, G4int n);
  G4double Laguerre(T* ptrT, F f, G4double alpha, G4int n);
  G4double Laguerre(G4double (*f)(G4double), G4double alpha, G4int n);
  //
  // Method involving Laguerre polynomials

  G4double Hermite(T& typeT, F f, G4int n);
  G4double Hermite(T* ptrT, F f, G4int n);
  G4double Hermite(G4double (*f)(G4double), G4int n);
  //
  // Method involving Hermite polynomials

  G4double Jacobi(T& typeT, F f, G4double alpha, G4double beta, G4int n);
  G4double Jacobi(T* ptrT, F f, G4double alpha, G4double beta, G4int n);
  G4double Jacobi(G4double (*f)(G4double), G4double alpha, G4double beta,
                  G4int n);
  // Method involving Jacobi polynomials

 protected:
  // Auxiliary functions for adaptive Gauss method

  G4double Gauss(T& typeT, F f, G4double a, G4double b);
  G4double Gauss(T* ptrT, F f, G4double a, G4double b);
  G4double Gauss(G4double (*f)(G4double), G4double a, G4double b);

  void AdaptGauss(T& typeT, F f, G4double a, G4double b, G4double e,
                  G4double& sum, G4int& n);
  void AdaptGauss(T* typeT, F f, G4double a, G4double b, G4double e,
                  G4double& sum, G4int& n);
  void AdaptGauss(G4double (*f)(G4double), G4double a, G4double b, G4double e,
                  G4double& sum, G4int& n);

  G4double GammaLogarithm(G4double xx);
};

#include "G4Integrator.icc"

#endif