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/Tensor.hpp"
       8             : #include "Evolution/Systems/CurvedScalarWave/Tags.hpp"
       9             : #include "Evolution/Systems/ScalarTensor/Tags.hpp"
      10             : #include "PointwiseFunctions/GeneralRelativity/Tags.hpp"
      11             : #include "Utilities/Gsl.hpp"
      12             : 
      13             : namespace ScalarTensor {
      14             : 
      15             : /*!
      16             :  * \brief Add in the source term to the \f$\Pi\f$
      17             :  * evolved variable of the ::CurvedScalarWave system.
      18             :  *
      19             :  * \details The only source term in the wave equation
      20             :  * \f[
      21             :  *  \Box \Psi = \mathcal{S} ~,
      22             :  *  \f]
      23             :  *
      24             :  * is in the equation for \f$\Pi\f$:
      25             :  * \f[
      26             :  *  \partial_t \Pi + \text{\{spatial derivative
      27             :  * terms\}} = \alpha \mathcal{S}
      28             :  * ~,
      29             :  * \f]
      30             :  *
      31             :  * where \f$\mathcal{S}\f$ is the source term (e. g. in the Klein-Gordon
      32             :  * equation, the source term is the derivative of the scalar potential
      33             :  * \f$\mathcal{S} \equiv \partial V / \partial \Psi \f$.)
      34             :  *
      35             :  * This function adds that contribution to the existing value of `dt_pi_scalar`.
      36             :  * The wave equation terms in the scalar equation should be computed before
      37             :  * passing the `dt_pi_scalar` to this function for updating.
      38             :  *
      39             :  * \param dt_pi_scalar Time derivative terms of $\Pi$. The sourceless part
      40             :  * should be computed before with ::CurvedScalarWave::TimeDerivative.
      41             :  * \param scalar_source Source term $\mathcal{S}$ for the scalar equation.
      42             :  * \param lapse Lapse $\alpha$.
      43             :  *
      44             :  * \see `CurvedScalarWave::TimeDerivative` for details about the source-less
      45             :  * part of the time derivative calculation.
      46             :  */
      47           1 : void add_scalar_source_to_dt_pi_scalar(
      48             :     gsl::not_null<Scalar<DataVector>*> dt_pi_scalar,
      49             :     const Scalar<DataVector>& scalar_source, const Scalar<DataVector>& lapse);
      50             : 
      51             : /*!
      52             :  * \brief Computes the source term given by the mass of the scalar.
      53             :  *
      54             :  * \details For a scalar field with mass parameter \f$ m_\Psi \f$,
      55             :  * the wave equation takes the form
      56             :  * \f[
      57             :  *   \Box \Psi = \mathcal{S} ~,
      58             :  * \f]
      59             :  *
      60             :  * where the source is given by
      61             :  * \f[
      62             :  *   \mathcal{S} \equiv m^2_\Psi \Psi~.
      63             :  * \f]
      64             :  *
      65             :  * Here the mass parameter value is an option that needs to be specified in the
      66             :  * input file.
      67             :  *
      68             :  * \param scalar_source Source term $\mathcal{S}$ for the scalar equation.
      69             :  * \param psi Scalar field $\Psi$.
      70             :  * \param mass_psi Mass of the scalar field $m_\Psi$.
      71             :  *
      72             :  * \see `ScalarTensor::Tags::ScalarMass` for details about the mass.
      73             :  */
      74           1 : void mass_source(gsl::not_null<Scalar<DataVector>*> scalar_source,
      75             :                  const Scalar<DataVector>& psi, const double mass_psi);
      76             : 
      77             : namespace Tags {
      78             : 
      79             : /*!
      80             :  * \brief Compute tag for the scalar source.
      81             :  *
      82             :  * \details Compute the scalar source from data box items using
      83             :  * `mass_source`.
      84             :  */
      85           1 : struct ScalarSourceCompute : ScalarSource, db::ComputeTag {
      86           0 :   using argument_tags =
      87             :       tmpl::list<CurvedScalarWave::Tags::Psi, ScalarTensor::Tags::ScalarMass>;
      88           0 :   using return_type = Scalar<DataVector>;
      89           0 :   static constexpr void (*function)(const gsl::not_null<return_type*> result,
      90             :                                     const Scalar<DataVector>&,
      91             :                                     const double) = &mass_source;
      92           0 :   using base = ScalarSource;
      93             : };
      94             : 
      95             : }  // namespace Tags
      96             : }  // namespace ScalarTensor