domain_bispheric_eta_first_for_metric.cpp

/*
    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/>.
*/
 
#include "headcpp.hpp"
 
#include "bispheric.hpp"
#include "term_eq.hpp"
#include "metric.hpp"
#include "scalar.hpp"
#include "tensor_impl.hpp"
 
namespace Kadath{
Term_eq Domain_bispheric_eta_first::derive_flat_cart (int type_der, char ind_der, const Term_eq& so, const Metric* manipulator) const {
 
    bool doder = (so.der_t==0x0) ? false : true ;
    if ((type_der==CON) && (manipulator->p_met_con[num_dom]->der_t==0x0))
      doder = false ;
 
    assert ((type_der==COV) || (type_der==CON)) ;
    int val_res = so.val_t->get_valence() + 1 ;
 
    bool doname = true ;
    if (so.val_t->get_valence()>0)
        if (!so.val_t->is_name_affected()) 
            doname = false;
 
    Array<int> type_ind (val_res) ;
    type_ind.set(0) = COV ;
    for (int i=1 ; i<val_res ; i++)
        type_ind.set(i) = so.val_t->get_index_type(i-1) ;
 
    // Need for summation ?
    bool need_sum = false ;
    if (doname)
        for (int i=1 ; i<val_res ; i++)
            if (ind_der== so.val_t->get_name_ind()[i-1])
                need_sum = true ;
 
    // Tensor for val
    Base_tensor basis (so.val_t->get_space(), CARTESIAN_BASIS) ;
    Tensor auxi_val (so.val_t->get_space(), val_res, type_ind, basis) ;
 
    
    // Set the names of the indices :
    if (doname) {
        auxi_val.set_name_affected() ;
        auxi_val.set_name_ind(0, ind_der) ;
        for (int i=1 ; i<val_res ; i++)
            auxi_val.set_name_ind(i, so.val_t->get_name_ind()[i-1]) ;
    }
 
    //Loop on the components :
    Index pos_auxi(auxi_val) ;
    Index pos_so (*so.val_t) ;
    do {
        for (int i=0 ; i<val_res-1 ; i++)
            pos_so.set(i) = pos_auxi(i+1) ;
        auxi_val.set(pos_auxi).set_domain(num_dom) = (*so.val_t)(pos_so)(num_dom).der_abs(pos_auxi(0)+1) ;
    }
    while (pos_auxi.inc()) ;
 
    if (!doder) {
        // No need for derivative :
        Term_eq auxi (num_dom, auxi_val) ;
        // If derive contravariant : manipulate first indice :
        if (type_der==CON) 
            manipulator->manipulate_ind (auxi, 0) ;
    
        if (!need_sum)
            return auxi ;
        else
            return Term_eq (num_dom, auxi.val_t->do_summation_one_dom(num_dom)) ;
    }
    else {
        // Need to compute the derivative :
        // Tensor for der   
        Tensor auxi_der (so.val_t->get_space(), val_res, type_ind, basis) ;
        // Set the names of the indices :
        auxi_der.set_name_affected() ;
        auxi_der.set_name_ind(0, ind_der) ;
        for (int i=1 ; i<val_res ; i++)
            auxi_der.set_name_ind(i, so.der_t->get_name_ind()[i-1]) ;
 
        //Loop on the components :
        Index pos_auxi_der(auxi_der) ;
        do {
            for (int i=0 ; i<val_res-1 ; i++)
                pos_so.set(i) = pos_auxi_der(i+1) ;
            auxi_der.set(pos_auxi_der).set_domain(num_dom) = (*so.der_t)(pos_so)(num_dom).der_abs(pos_auxi_der(0)+1) ;
        }
        while (pos_auxi_der.inc()) ;
 
        // Need for derivative :
        Term_eq auxi (num_dom, auxi_val, auxi_der) ;
        
        // If derive contravariant : manipulate first indice :
        if (type_der==CON)
            manipulator->manipulate_ind (auxi, 0) ;
        
        if (!need_sum)
            return auxi ;
        else 
          return Term_eq (num_dom, auxi.val_t->do_summation_one_dom(num_dom), 
                            auxi.der_t->do_summation_one_dom(num_dom)) ;
    }
 
}
}