3D specfem::sources::force_source implementation

template<>
class force<specfem::element::dimension_tag::dim3> : public specfem::sources::vector_source<specfem::element::dimension_tag::dim3>

Collocated force source.

This class implements a collocated force source in 3D that applies forces in the x, y, and z directions at a specific location in the simulation domain.

Usage Example

// Create a Ricker wavelet source time function
auto stf = std::make_unique<specfem::source_time_functions::Ricker>(
    15.0,  // dominant frequency (Hz)
    0.01,  // time factor
    1.0,   // amplitude
    0.0,   // time shift
    1.0,   // normalization factor
    false  // do not reverse
);

// Create a 3D force source at (1.0, 2.0, 3.0) with force components
auto force_source =
specfem::sources::force<specfem::element::dimension_tag::dim3>( 1.0,  //
x-coordinate 2.0,  // y-coordinate 3.0,  // z-coordinate 0.7,  // fx - force
in x direction 0.0,  // fy - force in y direction 0.7,  // fz - force in z
direction std::move(stf), specfem::simulation::field_type::forward
);

// Set the medium type
force_source.set_medium_tag(specfem::element::medium_tag::elastic);

// Get the force vector
auto force_vector = force_source.get_force_vector();

Public Functions

inline force()

Default source constructor.

inline force(YAML::Node &Node, const int nsteps, const type_real dt, const specfem::simulation::field_type wavefield_type)

Construct a new collocated force object.

Parameters:

• force_source – A YAML node defining force source

• dt – Time increment in the simulation. Used to calculate dominant frequecy of Dirac source.

inline force(type_real x, type_real y, type_real z, type_real fx, type_real fy, type_real fz, std::unique_ptr<specfem::source_time_functions::stf> source_time_function, const specfem::simulation::field_type wavefield_type)

Construct a new collocated force object.

Parameters:

• x – x-coordinate of source

• y – y-coordinate of source

• z – z-coordinate of source

• source_time_function – pointer to source time function

• wavefield_type – type of wavefield

inline force(std::unique_ptr<specfem::coordinate_systems::coordinates<specfem::element::dimension_tag::dim3>> coordinates, type_real fx, type_real fy, type_real fz, std::unique_ptr<specfem::source_time_functions::stf> source_time_function, const specfem::simulation::field_type wavefield_type)

Construct a new collocated force object from generic coordinates.

Parameters:

• coordinates – Generic coordinate object

• fx – Force in x-direction

• fy – Force in y-direction

• fz – Force in z-direction

• source_time_function – pointer to source time function

• wavefield_type – type of wavefield

inline virtual std::string source_name() const override

User output.

virtual std::string print_details() const override

Type-specific output (parameters unique to this source type). The default implementation returns an empty string for sources that have no additional parameters beyond location and source time function.

bool operator==(const specfem::sources::source<specfem::element::dimension_tag::dim3> &other) const override

Get the forcing function.

virtual Kokkos::View<type_real*, Kokkos::LayoutRight, Kokkos::HostSpace> get_force_vector() const override

Get the force vector.

Returns the 3D force vector for this source:

\[\begin{split} \mathbf{f}_{3D} = \begin{cases} [f_x] & \text{acoustic: pressure amplitude} \\ \begin{pmatrix} f_x \\ f_y \\ f_z \end{pmatrix} & \text{elastic: force components} \end{cases} \end{split}\]

Where:

• \(f_x, f_y, f_z\) are the user-specified force components

• For acoustic media, only the \(f_x\) component is used as pressure source

• For elastic media, all three components define the force vector

The force components are applied directly as body forces, representing point sources with user-specified directional amplitudes.

Returns:

Kokkos::View<type_real *, Kokkos::LayoutRight, Kokkos::HostSpace> Force vector with 3 components [fx, fy, fz]

virtual std::vector<specfem::element::medium_tag> get_supported_media() const override

Get the list of supported media for this source type.

Returns:

std::vector<specfem::element::medium_tag> list of supported media

inline virtual source_type get_source_type() const override

Get the source type object.

Returns:

source_type

inline type_real get_t0() const

Get the value of t0 from the specfem::stf::stf object.

Returns:

value of t0

inline void update_tshift(type_real tshift)

Update the value of tshift for specfem::stf::stf object.

Returns:

new value of tshift

inline std::optional<specfem::datetime::type> get_starttime() const

Get the UTC start time of this source (nullopt if not set).

inline void set_starttime(std::optional<specfem::datetime::type> t)

Set the UTC start time of this source.

inline std::string print() const

User output — assembles source name, location, type-specific details, source time function, and (when MPI-enabled) the owning rank.

void set_source_time_function(YAML::Node &Node, const int nsteps, const type_real dt)

Set the forcing function for the source.

This function initializes the source time function based on the configuration provided in the YAML node. It supports various types of source time functions such as Dirac, Gaussian, Ricker, dGaussian, Heaviside, and External. If the specified source time function is not recognized, an exception is thrown.

This method also is responsible for setting up the start time of the source time function depending on dimension (dim2, dim3) and forcing function type.

Parameters:

• Node – YAML node containing source time function configuration

• nsteps – number of time steps

• dt – time step size

inline std::unique_ptr<specfem::source_time_functions::stf> &get_source_time_function()

Get the forcing function object.

Returns:

std::unique_ptr<specfem::source_time_functions::stf>&

inline void set_local_coordinates(const specfem::point::local_coordinates<dimension_tag> &local_coordinates)

Set the local xi coordinates of the source in the local coordinate system.

Parameters:

specfem::point::local_coordinates<dimension_tag> – local_coordinates

inline specfem::point::local_coordinates<dimension_tag> get_local_coordinates() const

Get the local coordinates of the source in the local coordinate system.

Returns:

specfem::point::local_coordinates<dimension_tag>

inline void set_global_coordinates(const specfem::point::global_coordinates<dimension_tag> &global_coordinates)

Set the global coordinates of the source in the global coordinate system.

Parameters:

specfem::point::global_coordinates<dimension_tag> – global_coordinates

inline specfem::point::global_coordinates<dimension_tag> get_global_coordinates() const

Get the global coordinates of the source in the global coordinate system.

Returns:

specfem::point::global_coordinates<dimension_tag>

void set_medium_tag(specfem::element::medium_tag medium_tag)

Set the medium tag for the source.

This needs to be set inside the since each medium requires a separate implementation for each medium and some source do not have implementations for certain media at all. E.g., if you want to assign a moment tensor to an element in the water column (acoustic), it does not make sense, or rather it is unphysical.

Parameters:

medium_tag – medium tag

inline specfem::element::medium_tag get_medium_tag() const

Get the medium tag for the source.

Returns:

specfem::medium::medium_tag medium tag

inline void set_read_coordinates(std::unique_ptr<specfem::coordinate_systems::coordinates<dimension_tag>> coordinates)

Set the generic coordinates for this source.

Parameters:

coordinates – Generic coordinate object (ownership transferred)

inline const specfem::coordinate_systems::coordinates<dimension_tag> *get_read_coordinates() const

Get the generic coordinates (const), or nullptr if not set.

inline specfem::coordinate_systems::coordinates<dimension_tag> *get_read_coordinates()

Get the generic coordinates (mutable), or nullptr if not set.

Used by resolve_coordinates to set the origin on cartesian coordinates.