Class FACPreconditioner is a concrete LinearSolver for implementing FAC (multilevel multigrid) preconditioners. More...

#include </home/runner/work/IBAMR/IBAMR/ibtk/include/ibtk/FACPreconditioner.h>

Inheritance diagram for IBTK::FACPreconditioner:

[legend]

Public Member Functions
	FACPreconditioner (std::string object_name, SAMRAI::tbox::Pointer< FACPreconditionerStrategy > fac_strategy, SAMRAI::tbox::Pointer< SAMRAI::tbox::Database > input_db, const std::string &default_options_prefix)

	~FACPreconditioner ()

Linear solver functionality.
void	setHomogeneousBc (bool homogeneous_bc) override
	Set whether the solver should use homogeneous boundary conditions.

void	setSolutionTime (double solution_time) override
	Set the time at which the solution is to be evaluated.

void	setTimeInterval (double current_time, double new_time) override
	Set the current time interval.

bool	solveSystem (SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &x, SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &b) override
	Solve the linear system of equations for . More...

void	initializeSolverState (const SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &x, const SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &b) override
	Compute hierarchy dependent data required for solving . More...

void	deallocateSolverState () override
	Remove all hierarchy dependent data allocated by initializeSolverState(). More...

Public Member Functions inherited from IBTK::LinearSolver
	LinearSolver ()
	Constructor.

virtual	~LinearSolver ()
	Empty virtual destructor.

virtual void	setNullspace (bool nullspace_contains_constant_vec, const std::vector< SAMRAI::tbox::Pointer< SAMRAI::solv::SAMRAIVectorReal< NDIM, double > > > &nullspace_basis_vecs=std::vector< SAMRAI::tbox::Pointer< SAMRAI::solv::SAMRAIVectorReal< NDIM, double > > >())
	Set the nullspace of the linear system. More...

virtual bool	getNullspaceContainsConstantVector () const
	Get whether the nullspace of the linear system contains th constant vector.

virtual const std::vector< SAMRAI::tbox::Pointer< SAMRAI::solv::SAMRAIVectorReal< NDIM, double > > > &	getNullspaceBasisVectors () const
	Get the basis vectors for the nullspace of the linear system.

virtual bool	getInitialGuessNonzero () const
	Get whether the initial guess is non-zero.

virtual void	printClassData (std::ostream &stream) override
	Print class data to stream.

Public Member Functions inherited from IBTK::GeneralSolver
	GeneralSolver ()=default
	Constructor.

virtual	~GeneralSolver ()=default
	Empty virtual destructor.

const std::string &	getName () const
	Return the object name.

virtual bool	getIsInitialized () const
	Return whether the operator is initialized.

virtual bool	getHomogeneousBc () const
	Return whether the solver is using homogeneous boundary conditions.

virtual double	getSolutionTime () const
	Get the time at which the solution is being evaluated.

virtual std::pair< double, double >	getTimeInterval () const
	Get the current time interval.

virtual double	getDt () const
	Get the current time step size.

virtual void	setHierarchyMathOps (SAMRAI::tbox::Pointer< HierarchyMathOps > hier_math_ops)
	Set the HierarchyMathOps object used by the solver.

virtual SAMRAI::tbox::Pointer< HierarchyMathOps >	getHierarchyMathOps () const
	Get the HierarchyMathOps object used by the solver.

virtual int	getMaxIterations () const
	Get the maximum number of nonlinear iterations to use per solve.

virtual void	setAbsoluteTolerance (double abs_residual_tol)
	Set the absolute residual tolerance for convergence.

virtual double	getAbsoluteTolerance () const
	Get the absolute residual tolerance for convergence.

virtual void	setRelativeTolerance (double rel_residual_tol)
	Set the relative residual tolerance for convergence.

virtual double	getRelativeTolerance () const
	Get the relative residual tolerance for convergence.

virtual int	getNumIterations () const
	Return the iteration count from the most recent solve.

virtual double	getResidualNorm () const
	Return the residual norm from the most recent iteration.

virtual void	setLoggingEnabled (bool enable_logging=true)
	Enable or disable logging.

virtual bool	getLoggingEnabled () const
	Determine whether logging is enabled or disabled.

Functions to access solver parameters.
SAMRAI::tbox::Pointer< FACPreconditionerStrategy >	d_fac_strategy

SAMRAI::tbox::Pointer< SAMRAI::hier::PatchHierarchy< NDIM > >	d_hierarchy

int	d_coarsest_ln = 0

int	d_finest_ln = 0

MGCycleType	d_cycle_type = V_CYCLE

int	d_num_pre_sweeps = 0

int	d_num_post_sweeps = 2

void	setInitialGuessNonzero (bool initial_guess_nonzero=true) override
	Set whether the initial guess is non-zero.

void	setMaxIterations (int max_iterations) override
	Set the maximum number of iterations to use per solve.

void	setMGCycleType (MGCycleType cycle_type)
	Set the multigrid algorithm cycle type.

MGCycleType	getMGCycleType () const
	Get the multigrid algorithm cycle type.

void	setNumPreSmoothingSweeps (int num_pre_sweeps)
	Set the number of pre-smoothing sweeps to employ.

int	getNumPreSmoothingSweeps () const
	Get the number of pre-smoothing sweeps employed by the preconditioner.

void	setNumPostSmoothingSweeps (int num_post_sweeps)
	Set the number of post-smoothing sweeps to employ.

int	getNumPostSmoothingSweeps () const
	Get the number of post-smoothing sweeps employed by the preconditioner.

SAMRAI::tbox::Pointer< FACPreconditionerStrategy >	getFACPreconditionerStrategy () const
	Get the FAC preconditioner strategy objects employed by the preconditioner.

void	FACVCycleNoPreSmoothing (SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &u, SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &f, int level_num)

void	muCycle (SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &u, SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &f, SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &r, int level_num, int mu)

void	FCycle (SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &u, SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &f, SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &r, int level_num)

void	FMGCycle (SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &u, SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &f, SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &r, int level_num, int mu)

Additional Inherited Members
Protected Member Functions inherited from IBTK::GeneralSolver
void	init (const std::string &object_name, bool homogeneous_bc)

virtual void	initSpecialized (const std::string &object_name, bool homogeneous_bc)

Protected Attributes inherited from IBTK::LinearSolver
bool	d_initial_guess_nonzero = true

bool	d_nullspace_contains_constant_vec = false

std::vector< SAMRAI::tbox::Pointer< SAMRAI::solv::SAMRAIVectorReal< NDIM, double > > >	d_nullspace_basis_vecs

Protected Attributes inherited from IBTK::GeneralSolver
std::string	d_object_name = "unitialized"

bool	d_is_initialized = false

bool	d_homogeneous_bc = false

double	d_solution_time = std::numeric_limits<double>::quiet_NaN()

double	d_current_time = std::numeric_limits<double>::quiet_NaN()

double	d_new_time = std::numeric_limits<double>::quiet_NaN()

double	d_rel_residual_tol = 0.0

double	d_abs_residual_tol = 0.0

int	d_max_iterations = 100

int	d_current_iterations = 0

double	d_current_residual_norm = std::numeric_limits<double>::quiet_NaN()

SAMRAI::tbox::Pointer< HierarchyMathOps >	d_hier_math_ops

bool	d_hier_math_ops_external = false

bool	d_enable_logging = false

Detailed Description

Class FACPreconditioner is a concrete LinearSolver for implementing FAC (multilevel multigrid) preconditioners.

This class is similar to the SAMRAI class SAMRAI::solv::FACPreconditioner, except that this class has been optimized for the case in which the solver is to be used as a single-pass preconditioner, especially for the case in which pre-smoothing sweeps are not needed. This class is not suitable for use as a stand-alone solver; rather, it is intended to be used in conjunction with an iterative Krylov method.

Sample parameters for initialization from database (and their default values):

cycle_type = "V_CYCLE"  // see setMGCycleType()
num_pre_sweeps = 0      // see setNumPreSmoothingSweeps()
num_post_sweeps = 2     // see setNumPostSmoothingSweeps()
enable_logging = FALSE  // see setLoggingEnabled()

Constructor & Destructor Documentation

◆ FACPreconditioner()

IBTK::FACPreconditioner::FACPreconditioner	(	std::string	object_name,
		SAMRAI::tbox::Pointer< FACPreconditionerStrategy >	fac_strategy,
		SAMRAI::tbox::Pointer< SAMRAI::tbox::Database >	input_db,
		const std::string &	default_options_prefix
	)

Constructor.

◆ ~FACPreconditioner()

IBTK::FACPreconditioner::~FACPreconditioner ( )

Destructor.

Member Function Documentation

◆ deallocateSolverState()

void IBTK::FACPreconditioner::deallocateSolverState ( )

overridevirtual

Remove all hierarchy dependent data allocated by initializeSolverState().

When linear operator or preconditioner objects have been registered with this class via setOperator() and setPreconditioner(), they are also deallocated by this member function.

Note: It is safe to call deallocateSolverState() when the solver state is already deallocated.

See also: initializeSolverState

Reimplemented from IBTK::GeneralSolver.

◆ initializeSolverState()

void IBTK::FACPreconditioner::initializeSolverState	(	const SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &	x,
		const SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &	b
	)

overridevirtual

Compute hierarchy dependent data required for solving $Ax=b$ .

By default, the solveSystem() method computes some required hierarchy dependent data before solving and removes that data after the solve. For multiple solves that use the same hierarchy configuration, it is more efficient to:

initialize the hierarchy-dependent data required by the solver via initializeSolverState(),
solve the system one or more times via solveSystem(), and
remove the hierarchy-dependent data via deallocateSolverState().

Note that it is generally necessary to reinitialize the solver state when the hierarchy configuration changes.

When linear operator or preconditioner objects have been registered with this class via setOperator() and setPreconditioner(), they are also initialized by this member function.

Parameters

x	solution vector
b	right-hand-side vector

Conditions on Parameters:

vectors x and b must have same patch hierarchy
vectors x and b must have same structure, depth, etc.

Note: The vector arguments for solveSystem() need not match those for initializeSolverState(). However, there must be a certain degree of similarity, including:

hierarchy configuration (hierarchy pointer and range of levels)
number, type and alignment of vector component data
ghost cell widths of data in the solution x and right-hand-side b vectors

Note: It is safe to call initializeSolverState() when the state is already initialized. In this case, the solver state is first deallocated and then reinitialized.

See also: deallocateSolverState

Reimplemented from IBTK::GeneralSolver.

◆ solveSystem()

bool IBTK::FACPreconditioner::solveSystem	(	SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &	x,
		SAMRAI::solv::SAMRAIVectorReal< NDIM, double > &	b
	)

overridevirtual

Solve the linear system of equations $Ax=b$ for $x$ .

Before calling solveSystem(), the form of the solution x and right-hand-side b vectors must be set properly by the user on all patch interiors on the specified range of levels in the patch hierarchy. The user is responsible for all data management for the quantities associated with the solution and right-hand-side vectors. In particular, patch data in these vectors must be allocated prior to calling this method.

Parameters

x	solution vector
b	right-hand-side vector

Conditions on Parameters:

vectors x and b must have same patch hierarchy
vectors x and b must have same structure, depth, etc.

Note: The vector arguments for solveSystem() need not match those for initializeSolverState(). However, there must be a certain degree of similarity, including:

hierarchy configuration (hierarchy pointer and range of levels)
number, type and alignment of vector component data
ghost cell widths of data in the solution x and right-hand-side b vectors

Note: The solver need not be initialized prior to calling solveSystem(); however, see initializeSolverState() and deallocateSolverState() for opportunities to save overhead when performing multiple consecutive solves.

See also: initializeSolverState; deallocateSolverState

Returns: true if the solver converged to the specified tolerances, false otherwise

Implements IBTK::GeneralSolver.

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

/home/runner/work/IBAMR/IBAMR/ibtk/include/ibtk/FACPreconditioner.h
/home/runner/work/IBAMR/IBAMR/ibtk/src/solvers/impls/FACPreconditioner.cpp

Public Member Functions

Functions to access solver parameters.

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ FACPreconditioner()

◆ ~FACPreconditioner()

Member Function Documentation

◆ deallocateSolverState()

◆ initializeSolverState()

◆ solveSystem()