Line data    Source code

       1            0 : // Distributed under the MIT License.
       2              : // See LICENSE.txt for details.
       3              : 
       4              : #pragma once
       5              : 
       6              : #include "DataStructures/Tensor/Tensor.hpp"
       7              : #include "Utilities/Gsl.hpp"
       8              : #include "Utilities/MakeWithValue.hpp"
       9              : #include "Utilities/TMPL.hpp"
      10              : 
      11              : /// @{
      12              : /*!
      13              :  * \ingroup GeneralRelativityGroup
      14              :  * \brief Raises or lowers the first index of a rank 3 tensor which is symmetric
      15              :  * in the last two indices.
      16              :  *
      17              :  * \details If \f$T_{abc}\f$ is a tensor with \f$T_{abc} = T_{acb}\f$ and the
      18              :  * indices \f$a,b,c,...\f$ can represent either spatial or spacetime indices,
      19              :  * then the tensor \f$ T^a_{bc} = g^{ad} T_{abc} \f$ is computed, where \f$
      20              :  * g^{ab}\f$ is the inverse metric, which is either a spatial or spacetime
      21              :  * metric. If a tensor \f$ S^a_{bc} \f$ is passed as an argument than the
      22              :  * corresponding tensor \f$ S_{abc} \f$ is calculated with respect to the metric
      23              :  * \f$g_{ab}\f$.  You may have to add a new instantiation of this template if
      24              :  * you need a new use case.
      25              :  */
      26              : template <typename DataType, typename Index0, typename Index1>
      27            1 : void raise_or_lower_first_index(
      28              :     gsl::not_null<
      29              :         Tensor<DataType, Symmetry<2, 1, 1>,
      30              :                index_list<change_index_up_lo<Index0>, Index1, Index1>>*>
      31              :         result,
      32              :     const Tensor<DataType, Symmetry<2, 1, 1>,
      33              :                  index_list<Index0, Index1, Index1>>& tensor,
      34              :     const Tensor<DataType, Symmetry<1, 1>,
      35              :                  index_list<change_index_up_lo<Index0>,
      36              :                             change_index_up_lo<Index0>>>& metric);
      37              : 
      38              : template <typename DataType, typename Index0, typename Index1>
      39              : Tensor<DataType, Symmetry<2, 1, 1>,
      40              :        index_list<change_index_up_lo<Index0>, Index1, Index1>>
      41            1 : raise_or_lower_first_index(
      42              :     const Tensor<DataType, Symmetry<2, 1, 1>,
      43              :                  index_list<Index0, Index1, Index1>>& tensor,
      44              :     const Tensor<DataType, Symmetry<1, 1>,
      45              :                  index_list<change_index_up_lo<Index0>,
      46              :                             change_index_up_lo<Index0>>>& metric) {
      47              :   auto result = make_with_value<
      48              :       Tensor<DataType, Symmetry<2, 1, 1>,
      49              :              index_list<change_index_up_lo<Index0>, Index1, Index1>>>(metric,
      50              :                                                                       0.);
      51              :   raise_or_lower_first_index(make_not_null(&result), tensor, metric);
      52              :   return result;
      53              : }
      54              : /// @}
      55              : 
      56              : /// @{
      57              : /*!
      58              :  * \ingroup GeneralRelativityGroup
      59              :  * \brief Raises or lowers the index of a rank 1 tensor.
      60              :  *
      61              :  * \details If \f$T_{a}\f$ is a tensor and the
      62              :  * index \f$a\f$ can represent either a spatial or spacetime index,
      63              :  * then the tensor \f$ T^a = g^{ad} T_{d} \f$ is computed, where \f$
      64              :  * g^{ab}\f$ is the inverse metric, which is either a spatial or spacetime
      65              :  * metric. If a tensor \f$ S^a \f$ is passed as an argument than the
      66              :  * corresponding tensor \f$ S_{a} \f$ is calculated with respect to the metric
      67              :  * \f$g_{ab}\f$.
      68              :  */
      69              : template <typename DataTypeTensor, typename DataTypeMetric, typename Index0>
      70            1 : void raise_or_lower_index(
      71              :     gsl::not_null<Tensor<DataTypeTensor, Symmetry<1>,
      72              :                          index_list<change_index_up_lo<Index0>>>*>
      73              :         result,
      74              :     const Tensor<DataTypeTensor, Symmetry<1>, index_list<Index0>>& tensor,
      75              :     const Tensor<DataTypeMetric, Symmetry<1, 1>,
      76              :                  index_list<change_index_up_lo<Index0>,
      77              :                             change_index_up_lo<Index0>>>& metric);
      78              : 
      79              : template <typename DataTypeTensor, typename DataTypeMetric, typename Index0>
      80              : Tensor<DataTypeTensor, Symmetry<1>, index_list<change_index_up_lo<Index0>>>
      81            1 : raise_or_lower_index(
      82              :     const Tensor<DataTypeTensor, Symmetry<1>, index_list<Index0>>& tensor,
      83              :     const Tensor<DataTypeMetric, Symmetry<1, 1>,
      84              :                  index_list<change_index_up_lo<Index0>,
      85              :                             change_index_up_lo<Index0>>>& metric) {
      86              :   auto result = make_with_value<Tensor<DataTypeTensor, Symmetry<1>,
      87              :                                        index_list<change_index_up_lo<Index0>>>>(
      88              :       metric, 0.);
      89              :   raise_or_lower_index(make_not_null(&result), tensor, metric);
      90              :   return result;
      91              : }
      92              : /// @}