DirichletBC Class Reference

Custom boundary condition: Fixed Dirichlet BC at right boundary. More...

Inheritance diagram for DirichletBC:

Collaboration diagram for DirichletBC:

Public Member Functions
	DirichletBC (double value, double width=5.0)
const std::string &	get_modifier_name () const override
	Get the name of the field modifier.
void	apply (Model &model, double time) override
	Apply the field modification to the model (pure virtual)
Public Member Functions inherited from pfc::FieldModifier
void	set_field_name (const std::string &field_name)
const std::string &	get_field_name () const
virtual	~FieldModifier ()=default
	Destructor for the FieldModifier class.

Detailed Description

Custom boundary condition: Fixed Dirichlet BC at right boundary.

This demonstrates:

• Boundary condition application
• Smooth transition to avoid discontinuities
• Selective modification (only near boundaries)
• Time-independent BC (ignores time parameter)

Member Function Documentation

apply()

void DirichletBC::apply ( Model &  model, double  time  )

inlineoverridevirtual

Apply the field modification to the model (pure virtual)

This is the main interface method that derived classes must implement to define their modification logic. The method receives full mutable access to the Model and current simulation time, allowing arbitrary modifications.

Implementation Responsibilities:

• Retrieve field(s) via model.get_real_field() or model.get_complex_field()
• Access geometry via model.get_world() and model.get_fft()
• Modify field values according to modifier's purpose
• Handle MPI parallelism (operate on local subdomain)

Typical Implementation Pattern:

void apply(pfc::Model& model, double time) override {
  // 1. Get field to modify
  auto& field = model.get_real_field(get_field_name());
 
  // 2. Get geometry information
  const auto& world = model.get_world();
  const auto& fft = model.get_fft();
  auto inbox = pfc::fft::get_inbox(fft);
 
  // 3. Loop over local subdomain
  int idx = 0;
  for (int k = inbox.low[2]; k <= inbox.high[2]; k++) {
    for (int j = inbox.low[1]; j <= inbox.high[1]; j++) {
      for (int i = inbox.low[0]; i <= inbox.high[0]; i++) {
        // Compute modification based on position and/or time
        auto pos = pfc::world::to_coords(world, Int3{i, j, k});
        field[idx++] = compute_value(pos, time);
      }
    }
  }
}

Parameters

model	Mutable reference to the Model containing fields to modify
time	Current simulation time (useful for time-dependent BCs)

Precondition

Model must have the field specified by get_field_name() registered

Postcondition

Field values are modified according to modifier's logic

Note

For initial conditions, time is typically 0.0

For boundary conditions, time reflects current simulation time

Method is called on every MPI rank; each rank operates on its subdomain

Warning

Ensure modifications maintain physical correctness and don't violate model invariants (e.g., mass conservation if required)

See also

Model::get_real_field() for field access

Model::get_world() for domain geometry

Model::get_fft() for subdomain bounds

Implements pfc::FieldModifier.

get_modifier_name()

const std::string & DirichletBC::get_modifier_name ( ) const

inlineoverridevirtual

Get the name of the field modifier.

This function is responsible for getting the name of the field modifier.

Returns

The modifier name.

Reimplemented from pfc::FieldModifier.

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The documentation for this class was generated from the following file:

• /home/runner/work/OpenPFC/OpenPFC/docs/api/examples/07_field_modifiers.cpp