Line data    Source code

       1           0 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : #pragma once
       5             : 
       6             : #include <cstddef>
       7             : 
       8             : #include "DataStructures/Tensor/TypeAliases.hpp"
       9             : 
      10             : /// \cond
      11             : namespace gsl {
      12             : template <typename>
      13             : struct not_null;
      14             : }  // namespace gsl
      15             : /// \endcond
      16             : 
      17             : namespace gr {
      18             : /// @{
      19             : /*!
      20             :  * \ingroup GeneralRelativityGroup
      21             :  * \brief Compute null normal one-form to the boundary of a closed
      22             :  * region in a spatial slice of spacetime.
      23             :  *
      24             :  * \details Consider an \f$n-1\f$-dimensional boundary \f$S\f$ of a closed
      25             :  * region in an \f$n\f$-dimensional spatial hypersurface \f$\Sigma\f$. Let
      26             :  * \f$s^a\f$ be the unit spacelike vector orthogonal to \f$S\f$ in \f$\Sigma\f$,
      27             :  * and \f$n^a\f$ be the timelike unit vector orthogonal to \f$\Sigma\f$.
      28             :  * This function returns the null one-form that is outgoing/incoming on \f$S\f$:
      29             :  *
      30             :  * \f{align*}
      31             :  * k_a = \frac{1}{\sqrt{2}}\left(n_a \pm s_a\right).
      32             :  * \f}
      33             :  */
      34             : template <typename DataType, size_t VolumeDim, typename Frame>
      35           1 : tnsr::a<DataType, VolumeDim, Frame> interface_null_normal(
      36             :     const tnsr::a<DataType, VolumeDim, Frame>& spacetime_normal_one_form,
      37             :     const tnsr::i<DataType, VolumeDim, Frame>& interface_unit_normal_one_form,
      38             :     const double sign);
      39             : 
      40             : template <typename DataType, size_t VolumeDim, typename Frame>
      41           1 : void interface_null_normal(
      42             :     gsl::not_null<tnsr::a<DataType, VolumeDim, Frame>*> null_one_form,
      43             :     const tnsr::a<DataType, VolumeDim, Frame>& spacetime_normal_one_form,
      44             :     const tnsr::i<DataType, VolumeDim, Frame>& interface_unit_normal_one_form,
      45             :     const double sign);
      46             : /// @}
      47             : 
      48             : /*!
      49             :  * \ingroup GeneralRelativityGroup
      50             :  * \brief Compute null normal vector to the boundary of a closed
      51             :  * region in a spatial slice of spacetime.
      52             :  *
      53             :  * \details Consider an \f$n-1\f$-dimensional boundary \f$S\f$ of a closed
      54             :  * region in an \f$n\f$-dimensional spatial hypersurface \f$\Sigma\f$. Let
      55             :  * \f$s^a\f$ be the unit spacelike vector orthogonal to \f$S\f$ in \f$\Sigma\f$,
      56             :  * and \f$n^a\f$ be the timelike unit vector orthogonal to \f$\Sigma\f$.
      57             :  * This function returns the null vector that is outgoing/ingoing on \f$S\f$:
      58             :  *
      59             :  * \f{align*}
      60             :  * k^a = \frac{1}{\sqrt{2}}\left(n^a \pm s^a\right).
      61             :  * \f}
      62             :  */
      63             : template <typename DataType, size_t VolumeDim, typename Frame>
      64           1 : tnsr::A<DataType, VolumeDim, Frame> interface_null_normal(
      65             :     const tnsr::A<DataType, VolumeDim, Frame>& spacetime_normal_vector,
      66             :     const tnsr::I<DataType, VolumeDim, Frame>& interface_unit_normal_vector,
      67             :     const double sign);
      68             : 
      69             : /*!
      70             :  * \ingroup GeneralRelativityGroup
      71             :  * \brief Compute null normal vector to the boundary of a closed
      72             :  * region in a spatial slice of spacetime.
      73             :  *
      74             :  * \details Consider an \f$n-1\f$-dimensional boundary \f$S\f$ of a closed
      75             :  * region in an \f$n\f$-dimensional spatial hypersurface \f$\Sigma\f$. Let
      76             :  * \f$s^a\f$ be the unit spacelike vector orthogonal to \f$S\f$ in \f$\Sigma\f$,
      77             :  * and \f$n^a\f$ be the timelike unit vector orthogonal to \f$\Sigma\f$.
      78             :  * This function returns the null vector that is outgoing/ingoing on \f$S\f$:
      79             :  *
      80             :  * \f{align*}
      81             :  * k^a = \frac{1}{\sqrt{2}}\left(n^a \pm s^a\right).
      82             :  * \f}
      83             :  */
      84             : template <typename DataType, size_t VolumeDim, typename Frame>
      85             : void interface_null_normal(
      86             :     gsl::not_null<tnsr::A<DataType, VolumeDim, Frame>*> null_vector,
      87             :     const tnsr::A<DataType, VolumeDim, Frame>& spacetime_normal_vector,
      88             :     const tnsr::I<DataType, VolumeDim, Frame>& interface_unit_normal_vector,
      89             :     const double sign);
      90             : }  // namespace gr