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/DataBox/Tag.hpp"
       7             : #include "DataStructures/Tensor/TypeAliases.hpp"
       8             : #include "Evolution/Systems/ForceFree/Tags.hpp"
       9             : #include "PointwiseFunctions/GeneralRelativity/TagsDeclarations.hpp"
      10             : #include "Utilities/TMPL.hpp"
      11             : 
      12             : /// \cond
      13             : namespace Tags {
      14             : template <typename Tag>
      15             : struct Normalized;
      16             : }  // namespace Tags
      17             : namespace gsl {
      18             : template <typename T>
      19             : class not_null;
      20             : }  // namespace gsl
      21             : /// \endcond
      22             : 
      23             : namespace ForceFree {
      24           1 : namespace Tags {
      25             : /*!
      26             :  * \brief Compute the largest characteristic speed of the GRFFE system with
      27             :  * divergence cleaning.
      28             :  *
      29             :  * Wave speeds of the fast modes of the GRFFE system are the speed of light.
      30             :  *
      31             :  * \f{align*}
      32             :  *  \lambda_\pm = \beta^i\beta_i \pm \alpha
      33             :  * \f}
      34             :  *
      35             :  * where \f$\alpha\f$ is the lapse and \f$\beta^i\f$ is the shift. Therefore the
      36             :  * largest characteristic speed is \f$\lambda_\text{max} =
      37             :  * \sqrt{\beta_i\beta^i}+\alpha\f$.
      38             :  */
      39           1 : struct LargestCharacteristicSpeedCompute : LargestCharacteristicSpeed,
      40             :                                            db::ComputeTag {
      41           0 :   using argument_tags =
      42             :       tmpl::list<gr::Tags::Lapse<DataVector>, gr::Tags::Shift<DataVector, 3>,
      43             :                  gr::Tags::SpatialMetric<DataVector, 3>>;
      44           0 :   using return_type = double;
      45           0 :   using base = LargestCharacteristicSpeed;
      46           0 :   static void function(gsl::not_null<double*> speed,
      47             :                        const Scalar<DataVector>& lapse,
      48             :                        const tnsr::I<DataVector, 3>& shift,
      49             :                        const tnsr::ii<DataVector, 3>& spatial_metric);
      50             : };
      51             : 
      52             : }  // namespace Tags
      53             : }  // namespace ForceFree