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             : 
       9             : namespace ScalarTensor {
      10             : 
      11             : /*!
      12             :  * \brief Add in the source term to the \f$\Pi\f$
      13             :  * evolved variable of the ::CurvedScalarWave system.
      14             :  *
      15             :  * \details The only source term in the wave equation
      16             :  * \f[
      17             :  *  \Box \Psi = \mathcal{S} ~,
      18             :  *  \f]
      19             :  *
      20             :  * is in the equation for \f$\Pi\f$:
      21             :  * \f[
      22             :  *  \partial_t \Pi + \text{\{spatial derivative
      23             :  * terms\}} = \alpha \mathcal{S}
      24             :  * ~,
      25             :  * \f]
      26             :  *
      27             :  * where \f$\mathcal{S}\f$ is the source term (e. g. in the Klein-Gordon
      28             :  * equation, the source term is the derivative of the scalar potential
      29             :  * \f$\mathcal{S} \equiv \partial V / \partial \Psi \f$.)
      30             :  *
      31             :  * This function adds that contribution to the existing value of `dt_pi_scalar`.
      32             :  * The wave equation terms in the scalar equation should be computed before
      33             :  * passing the `dt_pi_scalar` to this function for updating.
      34             :  *
      35             :  * \param dt_pi_scalar Time derivative terms of $\Pi$. The sourceless part
      36             :  * should be computed before with ::CurvedScalarWave::TimeDerivative.
      37             :  * \param scalar_source Source term $\mathcal{S}$ for the scalar equation.
      38             :  * \param lapse Lapse $\alpha$.
      39             :  *
      40             :  * \see `CurvedScalarWave::TimeDerivative` for details about the source-less
      41             :  * part of the time derivative calculation.
      42             :  */
      43           1 : void add_scalar_source_to_dt_pi_scalar(
      44             :     gsl::not_null<Scalar<DataVector>*> dt_pi_scalar,
      45             :     const Scalar<DataVector>& scalar_source, const Scalar<DataVector>& lapse);
      46             : 
      47             : /*!
      48             :  * \brief Computes the source term given by the mass of the scalar.
      49             :  *
      50             :  * \details For a scalar field with mass parameter \f$ m_\Psi \f$,
      51             :  * the wave equation takes the form
      52             :  * \f[
      53             :  *   \Box \Psi = \mathcal{S} ~,
      54             :  * \f]
      55             :  *
      56             :  * where the source is given by
      57             :  * \f[
      58             :  *   \mathcal{S} \equiv m^2_\Psi \Psi~.
      59             :  * \f]
      60             :  *
      61             :  * Here the mass parameter value is an option that needs to be specified in the
      62             :  * input file.
      63             :  *
      64             :  * \param scalar_source Source term $\mathcal{S}$ for the scalar equation.
      65             :  * \param psi Scalar field $\Psi$.
      66             :  * \param mass_psi Mass of the scalar field $m_\Psi$.
      67             :  *
      68             :  * \see `ScalarTensor::Tags::ScalarMass` for details about the mass.
      69             :  */
      70           1 : void mass_source(gsl::not_null<Scalar<DataVector>*> scalar_source,
      71             :                  const Scalar<DataVector>& psi, double mass_psi);
      72             : 
      73             : }  // namespace ScalarTensor