metric_tensor.hpp

/*
    Copyright 2017 Philippe Grandclement
 
    This file is part of Kadath.
 
    Kadath 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 3 of the License, or
    (at your option) any later version.
 
    Kadath 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 Kadath.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#ifndef __METRIC_TENSOR_HPP_
#define __METRIC_TENSOR_HPP_
 
#include "tensor.hpp"
#include "gsl/gsl_permutation.h"
#include <vector>
#include <cmath>
 
namespace Kadath {
    double sign(gsl_permutation* p);
    vector<int> ind_com(int i, int j, int k, int l);
    int metric_tensor_position_array (const Array<int>& idx, int ndim);
    int metric_tensor_position_index (const Index& idx, int ndim);
    Array<int> metric_tensor_indices (int pos, int valence, int ndim);
 
    class Metric_tensor : public Tensor {
 
        public:
            Metric_tensor (const Space& sp, int type_descr, const Base_tensor& ba) ;
            Metric_tensor (const Metric_tensor&, bool copie = true) ;
            Metric_tensor (const Space& sp, FILE*) ; 
 
            // Assignement
            Metric_tensor & operator= (const Metric_tensor&) ; 
            Metric_tensor & operator= (const Tensor& a) override ;
            Metric_tensor & operator= (double xx) override ;
 
#ifdef TENSOR_MOVE_SEMANTIC
            Metric_tensor(Metric_tensor &&s) noexcept : Tensor{std::move(s)} {}
            Metric_tensor & operator=(Metric_tensor &&s) noexcept {this->Tensor::operator=(std::move(s)); return *this;}
#endif
 
            Metric_tensor inverse();
 
            void std_base2();
 
            int get_type() const {return type_indice(0) ;} ;
    } ;
 
    inline Metric_tensor::Metric_tensor (const Space& sp, int type_descr, const Base_tensor& bb) :
            Tensor (sp, 2, type_descr, 6, bb, 3) {
 
        give_place_array = metric_tensor_position_array ;
        give_place_index = metric_tensor_position_index ;
        give_indices = metric_tensor_indices ;
    }
 
    inline Metric_tensor::Metric_tensor (const Metric_tensor& so, bool copie) :
            Tensor (so, copie) {
    }
 
    inline Metric_tensor::Metric_tensor (const Space& sp, FILE* ff) :
            Tensor (sp, 3, ff) {
 
        assert (valence==2) ;
        assert (type_indice(0)==type_indice(1)) ;
        assert (n_comp==6) ;
 
        // Overwrite the storage functions :
        give_place_array = metric_tensor_position_array ;
        give_place_index = metric_tensor_position_index ;
        give_indices = metric_tensor_indices ;
    }
 
}
 
#endif