Class BGaussSeidelPreconditioner is a block Gauss-Seidel preconditioner which implements the abstract LinearSolver interface. More...

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

Inheritance diagram for IBTK::BGaussSeidelPreconditioner:

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Public Member Functions
	BGaussSeidelPreconditioner (std::string object_name, SAMRAI::tbox::Pointer< SAMRAI::tbox::Database > input_db, const std::string &default_options_prefix)
	Constructor.

	~BGaussSeidelPreconditioner ()
	Destructor.

void	setComponentPreconditioner (SAMRAI::tbox::Pointer< LinearSolver > preconditioner, unsigned int component)
	Set the preconditioner to be employed on the specified vector component.

void	setComponentOperators (const std::vector< SAMRAI::tbox::Pointer< LinearOperator > > &linear_ops, unsigned int component)
	Set the linear operators to be employed on the specified vector component.

void	setSymmetricPreconditioner (bool symmetric_preconditioner)
	Indicate whether to apply the component preconditioners symmetrically.

void	setReversedOrder (bool reverse_order)
	Indicate whether to apply the component preconditioners in reversed order (i.e., starting with the last component and ending with the first component).

Linear solver functionality.
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...

Functions to access solver parameters.
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.

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

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

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

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

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

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

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

Functions to access data on the most recent solve.
int	getNumIterations () const override
	Return the iteration count from the most recent linear solve.

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

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 BGaussSeidelPreconditioner is a block Gauss-Seidel preconditioner which implements the abstract LinearSolver interface.

This solver class performs a single block Gauss-Seidel sweep, applying specified component LinearSolver and LinearOperator objects to the components of a supplied SAMRAI::solv::SAMRAIVectorReal vector, and doing so in a multiplicative fashion. Note that the block Gauss-Seidel algorithm is not generally convergent, but can be used as a preconditioner for a KrylovLinearSolver.

Note that the default block Gauss-Seidel algorithm is not a symmetric linear operator, even if the individual component linear operators and solvers are symmetric. Instead, the algorithm applies the component preconditioners to the vector components starting with the first vector component and ending with the last vector component. The algorithm can be symmetrized via the setSymmetricPreconditioner() member function, and the order in which vector components are visited can be reversed via the setReversedOrder() member function.

Note: Class BJacobiPreconditioner implements the additive (i.e., block Jacobi) version of this algorithm.

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

symmetric_preconditioner = FALSE   // see setSymmetricPreconditioner()
reverse_order = FALSE              // see setReversedOrder()
initial_guess_nonzero = FALSE      // see setInitialGuessNonzero()
rel_residual_tol = 1.0e-6          // see setRelativeTolerance()
abs_residual_tol = 1.0e-30         // see setAbsoluteTolerance()
max_iterations = 1                 // see setMaxIterations()

Member Function Documentation

◆ deallocateSolverState()

void IBTK::BGaussSeidelPreconditioner::deallocateSolverState ( )

overridevirtual

Remove all hierarchy dependent data allocated by initializeSolverState().

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

See also: initializeSolverState

Reimplemented from IBTK::GeneralSolver.

◆ initializeSolverState()

void IBTK::BGaussSeidelPreconditioner::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.

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::BGaussSeidelPreconditioner::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/BGaussSeidelPreconditioner.h
/home/runner/work/IBAMR/IBAMR/ibtk/src/solvers/impls/BGaussSeidelPreconditioner.cpp

Public Member Functions

Functions to access data on the most recent solve.

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ deallocateSolverState()

◆ initializeSolverState()

◆ solveSystem()