integrand.h

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/*
 *  Copyright (C) 2007 Stefan Weinzierl
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
 
#ifndef __SECTOR_DECOMPOSITION_INTEGRAND_H__
#define __SECTOR_DECOMPOSITION_INTEGRAND_H__
 
#include <vector>
#include <cstddef>
#include <iostream>
 
#include <ginac/ginac.h>
 
#include "multi_index.h"
 
namespace sector_decomposition {
 
  class integration_data
    {
      // ctors
    public:
      integration_data(const std::vector<GiNaC::ex> & list_feynman_parameter, GiNaC::ex epsilon, int order);
 
      // member functions
    public:
 
      // I/O operators
      friend std::ostream & operator<< (std::ostream & os, const integration_data & arg);
 
      // member variables 
    public:
      size_t n;
      std::vector<GiNaC::ex> list_feynman_parameter;
 
      GiNaC::ex epsilon;
      int order;
    };
 
  class exponent
    {
      // ctors
    public:
      exponent();
      exponent(int order_0, int order_1);
      exponent(GiNaC::ex order_0, GiNaC::ex order_1);
 
      // member functions
    public:
      GiNaC::ex operator[](size_t i) const;
      exponent & sum_up(const exponent & other);
      exponent & subtract_off(const exponent & other);
      exponent & sum_up(const exponent & other, int lambda);
      exponent & subtract_off(const exponent & other, int lambda);
 
      int get_integer_part() const;
 
      GiNaC::ex get_exponent(const integration_data & global_data) const;
 
      bool is_not_zero() const;
 
      // I/O operators
      friend std::ostream & operator<< (std::ostream & os, const exponent & arg);
 
      // member variables 
    public:
      GiNaC::ex order_0;
      GiNaC::ex order_1;
    };
 
  class integrand
    {
      // ctors
    public:
      integrand();
      integrand(const std::vector<size_t> & index, const std::vector<exponent> & nu,
                const std::vector<GiNaC::ex> & poly_list, const std::vector<exponent> & c);
      integrand(const std::vector<exponent> & nu,
                const std::vector<GiNaC::ex> & poly_list, const std::vector<exponent> & c);
      integrand(size_t n,
                const std::vector<GiNaC::ex> & poly_list, const std::vector<exponent> & c);
      integrand(const std::vector<size_t> & index, const std::vector<exponent> & nu,
                const std::vector<GiNaC::ex> & poly_list, const std::vector<exponent> & c,
                GiNaC::ex extra_factor);
      integrand(const std::vector<size_t> & index, const std::vector<exponent> & nu,
                GiNaC::ex extra_factor);
      integrand(const std::vector<exponent> & nu,
                const std::vector<GiNaC::ex> & poly_list, const std::vector<exponent> & c,
                GiNaC::ex extra_factor);
      integrand(size_t n,
                const std::vector<GiNaC::ex> & poly_list, const std::vector<exponent> & c,
                GiNaC::ex extra_factor);
 
      // member functions
    public:
      GiNaC::ex get_integrand(const integration_data & global_data) const;
      GiNaC::ex get_weight_factor(const integration_data & global_data) const;
      GiNaC::ex get_polynomials(const integration_data & global_data) const;
      GiNaC::ex get_polynomials_without_exponent(const integration_data & global_data) const;
      GiNaC::ex get_extra_factor() const;
 
      bool check_homogeneous_polynomial(size_t k, const integration_data & global_data) const;
      int get_homogeneous_degree(size_t k, const integration_data & global_data) const;
      int get_degree(GiNaC::ex poly, const integration_data & global_data) const;
      void make_homogeneous(size_t k, const integration_data & global_data);
      void make_homogeneous(const integration_data & global_data);
 
      void restrict_to_primary_sector(size_t k, const integration_data & global_data);
      void restrict_to_primary_sector_cube(const multi_index_counter & index_set, const integration_data & global_data);
 
      bool check_zero(size_t k, const multi_index_ordered & index_set, const integration_data & global_data) const;
      bool check_zero(const multi_index_ordered & index_set, const integration_data & global_data) const;
 
      int get_ldegree(size_t k, const multi_index_ordered & index_set, const integration_data & global_data) const;
      int get_ldegree(const multi_index_ordered & index_set, const integration_data & global_data) const;
 
      GiNaC::ex get_polyhedra_polynomial(const integration_data & global_data) const;
      bool find_min_max(std::vector<size_t> & k_min_max_set, const integration_data & global_data);
      bool get_S_strategy_B(std::vector<size_t> & index_set, const integration_data & global_data);
      bool get_S_strategy_C(std::vector<size_t> & index_set, const integration_data & global_data);
 
 
      void create_subsector(size_t k, const std::vector<size_t> & index_set, const integration_data & global_data);
      void create_subsector(size_t k, const multi_index_ordered & index_set, const integration_data & global_data);
 
      int get_subtraction_vector(std::vector<size_t> & subtr_vec, std::vector<size_t> & index_set) const;
 
      GiNaC::ex taylor_term(GiNaC::ex polynomials, const multi_index_counter_indv & counter, const std::vector<size_t> & index_set, const integration_data & global_data) const;
 
      void integrated_taylor_term(const multi_index_counter_indv & counter, const std::vector<size_t> & index_set, const integration_data & global_data);
 
      // I/O operators
      friend std::ostream & operator<< (std::ostream & os, const integrand & arg);
 
      // member variables 
    public:
      std::vector<size_t> index;
 
      std::vector<exponent> weight;
 
      std::vector<GiNaC::ex> polynomial_list;
      std::vector<exponent> poly_exponent;
 
      GiNaC::ex extra_factor;
    };
 
} // namespace sector_decomposition
 
#endif // ndef __SECTOR_DECOMPOSITION_INTEGRAND_H__