#include <AMReX_MLMG.H>

Classes
class	error

Public Types
enum class	CFStrategy : int { none , ghostnodes }

using	MFType = MF

using	FAB = typename MLLinOpT< MF >::FAB

using	RT = typename MLLinOpT< MF >::RT

using	BCMode = typename MLLinOpT< MF >::BCMode

using	Location = typename MLLinOpT< MF >::Location

using	BottomSolver = amrex::BottomSolver

using	MultigridType = amrex::MultigridType

Public Member Functions
	MLMGT (MLLinOpT< MF > &a_lp)

	~MLMGT ()

	MLMGT (MLMGT< MF > const &)=delete

	MLMGT (MLMGT< MF > &&)=delete

MLMGT< MF > &	operator= (MLMGT< MF > const &)=delete

MLMGT< MF > &	operator= (MLMGT< MF > &&)=delete

template<typename AMF >
RT	solve (const Vector< AMF * > &a_sol, const Vector< AMF const * > &a_rhs, RT a_tol_rel, RT a_tol_abs, const char *checkpoint_file=nullptr)
	Solve the multilevel system; optional `checkpoint_file` is for debugging only.

template<typename AMF >
RT	solve (std::initializer_list< AMF * > a_sol, std::initializer_list< AMF const * > a_rhs, RT a_tol_rel, RT a_tol_abs, const char *checkpoint_file=nullptr)
	Convenience initializer-list overload that forwards to the Vector-based solve.

RT	precond (Vector< MF * > const &a_sol, Vector< MF const * > const &a_rhs, RT a_tol_rel, RT a_tol_abs)
	Apply MLMG as a right-preconditioner with relaxed tolerances.

template<typename AMF >
void	getGradSolution (const Vector< Array< AMF *, 3 > > &a_grad_sol, Location a_loc=Location::FaceCenter)
	Populate gradient components of the converged solution.

template<typename AMF >
void	getGradSolution (std::initializer_list< Array< AMF *, 3 > > a_grad_sol, Location a_loc=Location::FaceCenter)
	Initializer-list convenience overload for getGradSolution.

template<typename AMF >
void	getFluxes (const Vector< Array< AMF *, 3 > > &a_flux, Location a_loc=Location::FaceCenter)
	Face-centered flux helper (`-b grad(phi)` for `alpha a - beta div(b grad)`).

template<typename AMF >
void	getFluxes (std::initializer_list< Array< AMF *, 3 > > a_flux, Location a_loc=Location::FaceCenter)
	Initializer-list convenience overload for getFluxes (face-centered).

template<typename AMF >
void	getFluxes (const Vector< Array< AMF , 3 > > &a_flux, const Vector< AMF > &a_sol, Location a_loc=Location::FaceCenter)
	Face-centered flux helper that accepts an explicit solution vector.

template<typename AMF >
void	getFluxes (std::initializer_list< Array< AMF , 3 > > a_flux, std::initializer_list< AMF > a_sol, Location a_loc=Location::FaceCenter)
	Initializer-list convenience overload for the face-centered flux helper above.

template<typename AMF >
void	getFluxes (const Vector< AMF * > &a_flux, Location a_loc=Location::CellCenter)
	Cell-centered flux helper.

template<typename AMF >
void	getFluxes (std::initializer_list< AMF * > a_flux, Location a_loc=Location::CellCenter)
	Initializer-list convenience overload for cell-centered fluxes.

template<typename AMF >
void	getFluxes (const Vector< AMF * > &a_flux, const Vector< AMF * > &a_sol, Location a_loc=Location::CellCenter)
	Cell-centered flux helper that accepts an explicit solution vector.

template<typename AMF >
void	getFluxes (std::initializer_list< AMF * > a_flux, std::initializer_list< AMF * > a_sol, Location a_loc=Location::CellCenter)
	Initializer-list convenience overload for the cell-centered flux helper above.

void	compResidual (const Vector< MF * > &a_res, const Vector< MF * > &a_sol, const Vector< MF const * > &a_rhs)
	Compute multilevel residuals `a_rhs - L(a_sol)` on each AMR level.

void	getEBFluxes (const Vector< MF * > &a_eb_flux)
	Flux into the EB wall using the internally stored solution.

void	getEBFluxes (const Vector< MF * > &a_eb_flux, const Vector< MF * > &a_sol)
	Flux into the EB wall using an explicit solution vector.

void	apply (const Vector< MF * > &out, const Vector< MF * > &in)
	`out = L(in)`. Note that, if no actual solve is needed, one could turn off multigrid coarsening by constructing a MLLinOp object with an appropriate LPInfo object (e.g., with LPInfo().setMaxCoarseningLevel(0)).

void	applyPrecond (const Vector< MF * > &out, const Vector< MF * > &in)
	Apply the linear operator as a preconditioner (`out = L(in)`).

int	getVerbose () const

int	getBottomVerbose () const

void	incPrintIdentation ()
	Increase the indentation used when printing solver logs.

void	decPrintIdentation ()
	Decrease the indentation used when printing solver logs.

void	setThrowException (bool t) noexcept
	Control behavior when the solve fails to converge or blows up.

void	setVerbose (int v) noexcept
	Set the main solver verbosity (0 silent).

void	setMaxIter (int n) noexcept
	Cap the number of MLMG iterations executed.

void	setMaxFmgIter (int n) noexcept
	Cap the number of FMG cycles executed.

void	setFixedIter (int nit) noexcept
	Set the number of fixed MLMG iterations (convergence may still exit early if the residual is already small).

void	setPrecondIter (int nit) noexcept
	Set how many MLMG iterations the preconditioner executes per Krylov call (still subject to early-convergence checks).

void	setPreSmooth (int n) noexcept
	Number of pre-smoothing passes per V-cycle.

void	setPostSmooth (int n) noexcept
	Number of post-smoothing passes per V-cycle.

void	setFinalSmooth (int n) noexcept
	Number of smoothing passes when MLMG is used standalone (final smooth).

void	setBottomSmooth (int n) noexcept
	Additional smoothing passes executed after the bottom solver.

void	setBottomSolver (BottomSolver s) noexcept
	Select the bottom solver type (e.g., CG, BiCGStab, Hypre, PETSc).

BottomSolver	getBottomSolver () const noexcept

void	setMultigridType (MultigridType t) noexcept
	Select how AMR level 0 is solved. See MultigridType.

MultigridType	getMultigridType () const noexcept

bool	usedAlgMG () const noexcept

void	setAlgMGOptions (std::function< void(AlgMG< RT > &)> f)
	Adjust the AlgMG solvers MLMG builds (level 0 and bottom).

void	setHybridStallCriterion (int window, RT rate) noexcept
	Hybrid mode: switch to AlgMG when the residual has not dropped by `rate` per iteration on average over the last `window` iterations (defaults 0.8 and 4).

void	setHybridDivergenceFactor (RT f) noexcept

void	setCFStrategy (CFStrategy a_cf_strategy) noexcept
	Select the coarse-fine synchronization strategy.

void	setBottomVerbose (int v) noexcept
	Verbosity for the bottom solver (0 silent).

void	setBottomMaxIter (int n) noexcept
	Cap the number of iterations inside the bottom solver.

void	setBottomTolerance (RT t) noexcept
	Relative tolerance for the bottom solver.

void	setBottomToleranceAbs (RT t) noexcept
	Absolute tolerance for the bottom solver.

RT	getBottomToleranceAbs () const noexcept

void	setAlwaysUseBNorm (int flag) noexcept
	Deprecated flag for forcing B-norm convergence checks.

void	setConvergenceNormType (MLMGNormType norm) noexcept
	Choose the norm used for convergence tests.

void	setFinalFillBC (int flag) noexcept
	Force a FillBoundary at the end of the solve (nonzero enables).

int	numAMRLevels () const noexcept

void	setNSolve (int flag) noexcept
	Enable (`flag!=0`) or disable the N-solve path.

void	setNSolveGridSize (int s) noexcept
	Set the tile size used for N-solve builds.

void	setNoGpuSync (bool do_not_sync) noexcept
	Control implicit GPU synchronization inside solve().

void	prepareForFluxes (Vector< MF const * > const &a_sol)
	Build boundary caches needed by getFluxes()/compFluxes.

template<typename AMF >
void	prepareForSolve (Vector< AMF * > const &a_sol, Vector< AMF const * > const &a_rhs)
	Prepare linear operators, coefficients, and RHS data prior to solving.

void	prepareForNSolve ()
	Prepare the NSolve path.

void	prepareLinOp ()
	Finalize operator-dependent metadata before iterating.

void	preparePrecond ()
	Prepare preconditioner-specific caches (e.g., boundary data).

void	oneIter (int iter)
	Execute a single multigrid iteration (FMG or V-cycle).

void	miniCycle (int amrlev)
	Execute a per-level mini cycle.

void	mgVcycle (int amrlev, int mglev)
	Run a multigrid V-cycle on (`amrlev`,`mglev`).

void	mgFcycle ()
	Run an FMG cycle starting from the coarsest grid.

void	bottomSolve ()
	Execute the configured bottom solver (Hypre, PETSc, CG, etc.).

void	NSolve (MLMGT< MF > &a_solver, MF &a_sol, MF &a_rhs)
	Perform an NSolve using an MLMGT wrapper.

void	actualBottomSolve ()
	Execute the actual bottom solve after pre-smoothing and restriction.

void	postCG (int ret, int niters=-1)
	Post CG smoothing.

void	computeMLResidual (int amrlevmax)
	Compute the composite residual norm up to AMR level `amrlevmax`.

void	computeResidual (int alev)
	Compute the residual on AMR level `alev`.

void	computeResWithCrseSolFineCor (int calev, int falev)
	Residual update using coarse solution / fine correction.

void	computeResWithCrseCorFineCor (int falev)
	Residual update using coarse correction / fine correction.

void	interpCorrection (int alev)
	Interpolate corrections onto AMR level `alev`.

void	interpCorrection (int alev, int mglev)
	Interpolate corrections on (`alev`,`mglev`).

void	addInterpCorrection (int alev, int mglev)
	Add interpolated corrections to (`alev`,`mglev`) data.

void	computeResOfCorrection (int amrlev, int mglev)
	Compute the residual of the correction equation on (`amrlev`,`mglev`).

RT	ResNormInf (int alev, bool local=false)
	Infinity norm of the residual on level `alev`.

RT	MLResNormInf (int alevmax, bool local=false)
	Composite infinity norm of the residual up to level `alevmax`.

RT	MLRhsNormInf (bool local=false)
	Composite infinity norm of the RHS.

void	makeSolvable ()
	Adjust RHS/solution to satisfy null-space constraints.

void	makeSolvable (int amrlev, int mglev, MF &mf)
	Adjust a field on (`amrlev`,`mglev`) to satisfy null-space constraints.

int	bottomSolveWithCG (MF &x, const MF &b, typename MLCGSolverT< MF >::Type type)
	Bottom solve using CG/BiCGStab implemented in MLCGSolverT.

template<class TMF = MF> requires (std::same_as<TMF,MultiFab>)
void	bottomSolveWithAlgMG (MF &x, const MF &b)
	AlgMG on the bottom MG level (MultiFab, single component only).

template<class TMF = MF> requires (std::same_as<TMF,MultiFab>)
void	algmgLevel0Solve ()

template<class TMF = MF> requires (std::same_as<TMF,MultiFab>)
void	configureAlgMG (MLAlgMG &s, bool singular, bool with_options)

template<class TMF = MF> requires (std::same_as<TMF,MultiFab>)
void	algmgSolve (MLAlgMG &s, MF &x, MF const &b)

bool	hybridShouldSwitch (Vector< RT > const &norms, RT max_norm, RT best_norm, std::string &reason) const

RT	getInitRHS () const noexcept

RT	getInitResidual () const noexcept

RT	getFinalResidual () const noexcept

Vector< RT > const &	getResidualHistory () const noexcept

int	getNumIters () const noexcept

Vector< int > const &	getNumCGIters () const noexcept

MLLinOpT< MF > &	getLinOp ()

template<typename AMF >
auto	solve (std::initializer_list< AMF * > a_sol, std::initializer_list< AMF const * > a_rhs, RT a_tol_rel, RT a_tol_abs, const char *checkpoint_file) -> RT

template<typename AMF >
auto	solve (const Vector< AMF * > &a_sol, const Vector< AMF const * > &a_rhs, RT a_tol_rel, RT a_tol_abs, const char *checkpoint_file) -> RT

Friends
template<typename T >
class	MLCGSolverT

template<typename M >
class	GMRESMLMGT

Member Typedef Documentation

◆ BCMode

template<typename MF >

using amrex::MLMGT< MF >::BCMode = typename MLLinOpT<MF>::BCMode

◆ BottomSolver

template<typename MF >

using amrex::MLMGT< MF >::BottomSolver = amrex::BottomSolver

◆ FAB

template<typename MF >

using amrex::MLMGT< MF >::FAB = typename MLLinOpT<MF>::FAB

◆ Location

template<typename MF >

using amrex::MLMGT< MF >::Location = typename MLLinOpT<MF>::Location

◆ MFType

template<typename MF >

using amrex::MLMGT< MF >::MFType = MF

◆ MultigridType

template<typename MF >

using amrex::MLMGT< MF >::MultigridType = amrex::MultigridType

◆ RT

template<typename MF >

using amrex::MLMGT< MF >::RT = typename MLLinOpT<MF>::RT

Member Enumeration Documentation

◆ CFStrategy

template<typename MF >

enum class amrex::MLMGT::CFStrategy : int

strong

Enumerator
none
ghostnodes

Constructor & Destructor Documentation

◆ MLMGT() [1/3]

template<typename MF >

amrex::MLMGT< MF >::MLMGT ( MLLinOpT< MF > & a_lp )

◆ ~MLMGT()

template<typename MF >

amrex::MLMGT< MF >::~MLMGT ( )

default

◆ MLMGT() [2/3]

template<typename MF >

amrex::MLMGT< MF >::MLMGT ( MLMGT< MF > const & )

delete

◆ MLMGT() [3/3]

template<typename MF >

amrex::MLMGT< MF >::MLMGT ( MLMGT< MF > && )

delete

Member Function Documentation

◆ actualBottomSolve()

template<typename MF >

void amrex::MLMGT< MF >::actualBottomSolve ( )

Execute the actual bottom solve after pre-smoothing and restriction.

◆ addInterpCorrection()

template<typename MF >

void amrex::MLMGT< MF >::addInterpCorrection	(	int	alev,
		int	mglev
	)

Add interpolated corrections to (alev,mglev) data.

Parameters

alev	AMR level index.
mglev	Multigrid level index.

◆ algmgLevel0Solve()

template<typename MF >
requires (std::same_as<TMF,MultiFab>)

template<class TMF >
requires (std::same_as<TMF,MultiFab>)

void amrex::MLMGT< MF >::algmgLevel0Solve ( )

AlgMG on the finest MG level of AMR level 0: res[0][0] -> cor[0][0] (one V-cycle in preconditioner mode).

◆ algmgSolve()

template<typename MF >
requires (std::same_as<TMF,MultiFab>)

template<class TMF >
requires (std::same_as<TMF,MultiFab>)

void amrex::MLMGT< MF >::algmgSolve	(	MLAlgMG &	s,
		MF &	x,
		MF const &	b
	)

◆ apply()

template<typename MF >

void amrex::MLMGT< MF >::apply	(	const Vector< MF * > &	out,
		const Vector< MF * > &	in
	)

out = L(in). Note that, if no actual solve is needed, one could turn off multigrid coarsening by constructing a MLLinOp object with an appropriate LPInfo object (e.g., with LPInfo().setMaxCoarseningLevel(0)).

◆ applyPrecond()

template<typename MF >

void amrex::MLMGT< MF >::applyPrecond	(	const Vector< MF * > &	out,
		const Vector< MF * > &	in
	)

Apply the linear operator as a preconditioner (out = L(in)).

Parameters

out	Destination vectors (per level).
in	Source vectors (per level).

◆ bottomSolve()

template<typename MF >

void amrex::MLMGT< MF >::bottomSolve ( )

Execute the configured bottom solver (Hypre, PETSc, CG, etc.).

◆ bottomSolveWithAlgMG()

template<typename MF >
requires (std::same_as<TMF,MultiFab>)

template<class TMF >
requires (std::same_as<TMF,MultiFab>)

void amrex::MLMGT< MF >::bottomSolveWithAlgMG	(	MF &	x,
		const MF &	b
	)

AlgMG on the bottom MG level (MultiFab, single component only).

◆ bottomSolveWithCG()

template<typename MF >

int amrex::MLMGT< MF >::bottomSolveWithCG	(	MF &	x,
		const MF &	b,
		typename MLCGSolverT< MF >::Type	type
	)

Bottom solve using CG/BiCGStab implemented in MLCGSolverT.

Parameters

x	Solution vector updated in place.
b	Right-hand side.
type	Krylov flavor (CG or BiCGStab).

Returns: Status code from the Krylov solver.

◆ compResidual()

template<typename MF >

void amrex::MLMGT< MF >::compResidual	(	const Vector< MF * > &	a_res,
		const Vector< MF * > &	a_sol,
		const Vector< MF const * > &	a_rhs
	)

Compute multilevel residuals a_rhs - L(a_sol) on each AMR level.

Parameters

a_res	Residual `MF` s per level (output).
a_sol	Solution `MF` s per level.
a_rhs	Right-hand sides per level.

◆ computeMLResidual()

template<typename MF >

void amrex::MLMGT< MF >::computeMLResidual ( int amrlevmax )

Compute the composite residual norm up to AMR level amrlevmax.

Parameters

amrlevmax Finest AMR level included in the composite norm.

◆ computeResidual()

template<typename MF >

void amrex::MLMGT< MF >::computeResidual ( int alev )

Compute the residual on AMR level alev.

Parameters

alev	AMR level whose residual is refreshed.

◆ computeResOfCorrection()

template<typename MF >

void amrex::MLMGT< MF >::computeResOfCorrection	(	int	amrlev,
		int	mglev
	)

Compute the residual of the correction equation on (amrlev,mglev).

Parameters

amrlev	AMR level index.
mglev	Multigrid level index.

◆ computeResWithCrseCorFineCor()

template<typename MF >

void amrex::MLMGT< MF >::computeResWithCrseCorFineCor ( int falev )

Residual update using coarse correction / fine correction.

Parameters

falev Fine AMR level index supplying the correction.

◆ computeResWithCrseSolFineCor()

template<typename MF >

void amrex::MLMGT< MF >::computeResWithCrseSolFineCor	(	int	calev,
		int	falev
	)

Residual update using coarse solution / fine correction.

Parameters

calev	Coarse AMR level index.
falev	Fine AMR level index.

◆ configureAlgMG()

template<typename MF >
requires (std::same_as<TMF,MultiFab>)

template<class TMF >
requires (std::same_as<TMF,MultiFab>)

void amrex::MLMGT< MF >::configureAlgMG	(	MLAlgMG &	s,
		bool	singular,
		bool	with_options
	)

◆ decPrintIdentation()

template<typename MF >

void amrex::MLMGT< MF >::decPrintIdentation ( )

Decrease the indentation used when printing solver logs.

◆ getBottomSolver()

template<typename MF >

BottomSolver amrex::MLMGT< MF >::getBottomSolver ( ) const

inlinenoexcept

◆ getBottomToleranceAbs()

template<typename MF >

RT amrex::MLMGT< MF >::getBottomToleranceAbs ( ) const

inlinenoexcept

◆ getBottomVerbose()

template<typename MF >

int amrex::MLMGT< MF >::getBottomVerbose ( ) const

inline

◆ getEBFluxes() [1/2]

template<typename MF >

void amrex::MLMGT< MF >::getEBFluxes ( const Vector< MF * > & a_eb_flux )

Flux into the EB wall using the internally stored solution.

Parameters

a_eb_flux Per-level MF s that receive wall fluxes.

◆ getEBFluxes() [2/2]

template<typename MF >

void amrex::MLMGT< MF >::getEBFluxes	(	const Vector< MF * > &	a_eb_flux,
		const Vector< MF * > &	a_sol
	)

Flux into the EB wall using an explicit solution vector.

Parameters

a_eb_flux	Per-level `MF` s that receive wall fluxes.
a_sol	Explicit solution `MF` s per level.

◆ getFinalResidual()

template<typename MF >

RT amrex::MLMGT< MF >::getFinalResidual ( ) const

inlinenoexcept

◆ getFluxes() [1/8]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getFluxes	(	const Vector< AMF * > &	a_flux,
		const Vector< AMF * > &	a_sol,
		Location	a_loc = `Location::CellCenter`
	)

Cell-centered flux helper that accepts an explicit solution vector.

Parameters

a_flux	Destination `MF` s (one per level).
a_sol	Explicit solution `MF` s.
a_loc	Location at which fluxes are evaluated.

◆ getFluxes() [2/8]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getFluxes	(	const Vector< AMF * > &	a_flux,
		Location	a_loc = `Location::CellCenter`
	)

Cell-centered flux helper.

Parameters

a_flux	Destination `MF` s (one per level).
a_loc	Location at which fluxes are evaluated (cell centers by default).

◆ getFluxes() [3/8]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getFluxes	(	const Vector< Array< AMF *, 3 > > &	a_flux,
		const Vector< AMF * > &	a_sol,
		Location	a_loc = `Location::FaceCenter`
	)

Face-centered flux helper that accepts an explicit solution vector.

Parameters

a_flux	Destination arrays for per-face fluxes (per level).
a_sol	Explicit solution vectors per level.
a_loc	Location at which fluxes are evaluated.

◆ getFluxes() [4/8]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getFluxes	(	const Vector< Array< AMF *, 3 > > &	a_flux,
		Location	a_loc = `Location::FaceCenter`
	)

Face-centered flux helper (-b grad(phi) for alpha a - beta div(b grad)).

Parameters

a_flux	Destination arrays for per-face fluxes (per level).
a_loc	Location at which fluxes are evaluated.

◆ getFluxes() [5/8]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getFluxes	(	std::initializer_list< AMF * >	a_flux,
		Location	a_loc = `Location::CellCenter`
	)

Initializer-list convenience overload for cell-centered fluxes.

Parameters

a_flux	Initializer list of destination `MF` s.
a_loc	Location at which fluxes are evaluated.

◆ getFluxes() [6/8]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getFluxes	(	std::initializer_list< AMF * >	a_flux,
		std::initializer_list< AMF * >	a_sol,
		Location	a_loc = `Location::CellCenter`
	)

Initializer-list convenience overload for the cell-centered flux helper above.

Parameters

a_flux	Initializer list of destination `MF` s.
a_sol	Initializer list of solution `MF` s.
a_loc	Location at which fluxes are evaluated.

◆ getFluxes() [7/8]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getFluxes	(	std::initializer_list< Array< AMF *, 3 > >	a_flux,
		Location	a_loc = `Location::FaceCenter`
	)

Initializer-list convenience overload for getFluxes (face-centered).

Parameters

a_flux	Initializer list converted to a temporary Vector.
a_loc	Location at which fluxes are evaluated.

◆ getFluxes() [8/8]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getFluxes	(	std::initializer_list< Array< AMF *, 3 > >	a_flux,
		std::initializer_list< AMF * >	a_sol,
		Location	a_loc = `Location::FaceCenter`
	)

Initializer-list convenience overload for the face-centered flux helper above.

Parameters

a_flux	Initializer list converted to a temporary Vector.
a_sol	Initializer list of solution pointers converted to a Vector.
a_loc	Location at which fluxes are evaluated.

◆ getGradSolution() [1/2]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getGradSolution	(	const Vector< Array< AMF *, 3 > > &	a_grad_sol,
		Location	a_loc = `Location::FaceCenter`
	)

Populate gradient components of the converged solution.

Parameters

a_grad_sol	Output gradient arrays (per level and direction) updated in place.
a_loc	Location to sample the gradient (face center by default).

◆ getGradSolution() [2/2]

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::getGradSolution	(	std::initializer_list< Array< AMF *, 3 > >	a_grad_sol,
		Location	a_loc = `Location::FaceCenter`
	)

Initializer-list convenience overload for getGradSolution.

Parameters

a_grad_sol	Initializer list converted to a temporary Vector.
a_loc	Location to sample the gradient (face center by default).

◆ getInitResidual()

template<typename MF >

RT amrex::MLMGT< MF >::getInitResidual ( ) const

inlinenoexcept

◆ getInitRHS()

template<typename MF >

RT amrex::MLMGT< MF >::getInitRHS ( ) const

inlinenoexcept

◆ getLinOp()

template<typename MF >

MLLinOpT< MF > & amrex::MLMGT< MF >::getLinOp ( )

inline

◆ getMultigridType()

template<typename MF >

MultigridType amrex::MLMGT< MF >::getMultigridType ( ) const

inlinenoexcept

◆ getNumCGIters()

template<typename MF >

Vector< int > const & amrex::MLMGT< MF >::getNumCGIters ( ) const

inlinenoexcept

◆ getNumIters()

template<typename MF >

int amrex::MLMGT< MF >::getNumIters ( ) const

inlinenoexcept

◆ getResidualHistory()

template<typename MF >

Vector< RT > const & amrex::MLMGT< MF >::getResidualHistory ( ) const

inlinenoexcept

◆ getVerbose()

template<typename MF >

int amrex::MLMGT< MF >::getVerbose ( ) const

inline

◆ hybridShouldSwitch()

template<typename MF >

bool amrex::MLMGT< MF >::hybridShouldSwitch	(	Vector< RT > const &	norms,
		RT	max_norm,
		RT	best_norm,
		std::string &	reason
	)		const

Hybrid mode: is it time to give up on the geometric phase? norms holds the residual norms of the geometric iterations so far.

◆ incPrintIdentation()

template<typename MF >

void amrex::MLMGT< MF >::incPrintIdentation ( )

Increase the indentation used when printing solver logs.

◆ interpCorrection() [1/2]

template<typename MF >

void amrex::MLMGT< MF >::interpCorrection ( int alev )

Interpolate corrections onto AMR level alev.

Parameters

alev	AMR level receiving the correction.

◆ interpCorrection() [2/2]

template<typename MF >

void amrex::MLMGT< MF >::interpCorrection	(	int	alev,
		int	mglev
	)

Interpolate corrections on (alev,mglev).

Parameters

alev	AMR level index.
mglev	Multigrid level index.

◆ makeSolvable() [1/2]

template<typename MF >

void amrex::MLMGT< MF >::makeSolvable ( )

Adjust RHS/solution to satisfy null-space constraints.

◆ makeSolvable() [2/2]

template<typename MF >

void amrex::MLMGT< MF >::makeSolvable	(	int	amrlev,
		int	mglev,
		MF &	mf
	)

Adjust a field on (amrlev,mglev) to satisfy null-space constraints.

Parameters

amrlev	AMR level index.
mglev	Multigrid level index.
mf	`MF` updated in place.

◆ mgFcycle()

template<typename MF >

void amrex::MLMGT< MF >::mgFcycle ( )

Run an FMG cycle starting from the coarsest grid.

◆ mgVcycle()

template<typename MF >

void amrex::MLMGT< MF >::mgVcycle	(	int	amrlev,
		int	mglev
	)

Run a multigrid V-cycle on (amrlev,mglev).

Parameters

amrlev	AMR level index whose V-cycle is executed.
mglev	Multigrid level index that seeds the descent.

◆ miniCycle()

template<typename MF >

void amrex::MLMGT< MF >::miniCycle ( int amrlev )

Execute a per-level mini cycle.

Parameters

amrlev AMR level that triggers the synchronization.

◆ MLResNormInf()

template<typename MF >

auto amrex::MLMGT< MF >::MLResNormInf	(	int	alevmax,
		bool	local = `false`
	)

Composite infinity norm of the residual up to level alevmax.

Parameters

alevmax	Finest AMR level included.
local	True to skip MPI reductions.

◆ MLRhsNormInf()

template<typename MF >

auto amrex::MLMGT< MF >::MLRhsNormInf ( bool local = false )

Composite infinity norm of the RHS.

Parameters

local True to skip MPI reductions.

◆ NSolve()

template<typename MF >

void amrex::MLMGT< MF >::NSolve	(	MLMGT< MF > &	a_solver,
		MF &	a_sol,
		MF &	a_rhs
	)

Perform an NSolve using an MLMGT wrapper.

Parameters

a_solver	Helper solver object.
a_sol	Nodal solution updated in place.
a_rhs	Nodal RHS.

◆ numAMRLevels()

template<typename MF >

int amrex::MLMGT< MF >::numAMRLevels ( ) const

inlinenoexcept

◆ oneIter()

template<typename MF >

void amrex::MLMGT< MF >::oneIter ( int iter )

Execute a single multigrid iteration (FMG or V-cycle).

Parameters

iter	Iteration index (starting at zero).

◆ operator=() [1/2]

template<typename MF >

MLMGT< MF > & amrex::MLMGT< MF >::operator= ( MLMGT< MF > && )

delete

◆ operator=() [2/2]

template<typename MF >

MLMGT< MF > & amrex::MLMGT< MF >::operator= ( MLMGT< MF > const & )

delete

◆ postCG()

template<typename MF >

void amrex::MLMGT< MF >::postCG	(	int	ret,
		int	niters = `-1`
	)

Post CG smoothing.

Parameters

ret	Return code of the previous CG solver.
niters	Number of iterations of the previous CG solver to record for getNumCGIters(). Pass a negative number if it has already been recorded (e.g., by bottomSolveWithCG).

◆ precond()

template<typename MF >

auto amrex::MLMGT< MF >::precond	(	Vector< MF * > const &	a_sol,
		Vector< MF const * > const &	a_rhs,
		RT	a_tol_rel,
		RT	a_tol_abs
	)

Apply MLMG as a right-preconditioner with relaxed tolerances.

Parameters

a_sol	Destination (acts like the correction).
a_rhs	Source residual that should be smoothed.
a_tol_rel	Relative tolerance passed to the inner solve.
a_tol_abs	Absolute tolerance passed to the inner solve.

Returns: Residual norm reported by the inner V-cycle.

◆ prepareForFluxes()

template<typename MF >

void amrex::MLMGT< MF >::prepareForFluxes ( Vector< MF const * > const & a_sol )

Build boundary caches needed by getFluxes()/compFluxes.

Parameters

a_sol Solution MF s per level (const pointers).

◆ prepareForNSolve()

template<typename MF >

void amrex::MLMGT< MF >::prepareForNSolve ( )

Prepare the NSolve path.

◆ prepareForSolve()

template<typename MF >

template<typename AMF >

void amrex::MLMGT< MF >::prepareForSolve	(	Vector< AMF * > const &	a_sol,
		Vector< AMF const * > const &	a_rhs
	)

Prepare linear operators, coefficients, and RHS data prior to solving.

Parameters

a_sol	Initial guesses per level (updated in place as needed).
a_rhs	Right-hand sides per level.

◆ prepareLinOp()

template<typename MF >

void amrex::MLMGT< MF >::prepareLinOp ( )

Finalize operator-dependent metadata before iterating.

◆ preparePrecond()

template<typename MF >

void amrex::MLMGT< MF >::preparePrecond ( )

Prepare preconditioner-specific caches (e.g., boundary data).

◆ ResNormInf()

template<typename MF >

auto amrex::MLMGT< MF >::ResNormInf	(	int	alev,
		bool	local = `false`
	)

Infinity norm of the residual on level alev.

Parameters

alev	AMR level index.
local	True to skip MPI reductions.

◆ setAlgMGOptions()

template<typename MF >

void amrex::MLMGT< MF >::setAlgMGOptions ( std::function< void(AlgMG< RT > &)> f )

inline

Adjust the AlgMG solvers MLMG builds (level 0 and bottom).

The callback runs once, when a solver is built for an assembled matrix, so it can set the multigrid parameters (Krylov acceleration, smoother, interpolation, strength, coarsening) without repeating the setup. MLMG applies its own bottom tolerances, iteration limit, verbosity, exception and singularity settings on every solve; those cannot be changed here.

◆ setAlwaysUseBNorm()

template<typename MF >

void amrex::MLMGT< MF >::setAlwaysUseBNorm ( int flag )

noexcept

Deprecated flag for forcing B-norm convergence checks.

Parameters

flag	Nonzero to always use the B-norm.

◆ setBottomMaxIter()

template<typename MF >

void amrex::MLMGT< MF >::setBottomMaxIter ( int n )

inlinenoexcept

Cap the number of iterations inside the bottom solver.

Parameters

n	Maximum iterations for the bottom solve.

◆ setBottomSmooth()

template<typename MF >

void amrex::MLMGT< MF >::setBottomSmooth ( int n )

inlinenoexcept

Additional smoothing passes executed after the bottom solver.

Parameters

n	Bottom smoother iterations.

◆ setBottomSolver()

template<typename MF >

void amrex::MLMGT< MF >::setBottomSolver ( BottomSolver s )

inlinenoexcept

Select the bottom solver type (e.g., CG, BiCGStab, Hypre, PETSc).

Parameters

s	Bottom solver enum.

◆ setBottomTolerance()

template<typename MF >

void amrex::MLMGT< MF >::setBottomTolerance ( RT t )

inlinenoexcept

Relative tolerance for the bottom solver.

Parameters

t	Relative tolerance.

◆ setBottomToleranceAbs()

template<typename MF >

void amrex::MLMGT< MF >::setBottomToleranceAbs ( RT t )

inlinenoexcept

Absolute tolerance for the bottom solver.

Parameters

t	Absolute tolerance.

◆ setBottomVerbose()

template<typename MF >

void amrex::MLMGT< MF >::setBottomVerbose ( int v )

inlinenoexcept

Verbosity for the bottom solver (0 silent).

Parameters

v	Bottom-solver verbosity level.

◆ setCFStrategy()

template<typename MF >

void amrex::MLMGT< MF >::setCFStrategy ( CFStrategy a_cf_strategy )

inlinenoexcept

Select the coarse-fine synchronization strategy.

Parameters

a_cf_strategy Strategy enum governing CF handling.

◆ setConvergenceNormType()

template<typename MF >

void amrex::MLMGT< MF >::setConvergenceNormType ( MLMGNormType norm )

inlinenoexcept

Choose the norm used for convergence tests.

Parameters

norm	Norm type (residual, RHS, etc.).

◆ setFinalFillBC()

template<typename MF >

void amrex::MLMGT< MF >::setFinalFillBC ( int flag )

inlinenoexcept

Force a FillBoundary at the end of the solve (nonzero enables).

Parameters

flag	Nonzero to fill BCs after convergence.

◆ setFinalSmooth()

template<typename MF >

void amrex::MLMGT< MF >::setFinalSmooth ( int n )

inlinenoexcept

Number of smoothing passes when MLMG is used standalone (final smooth).

Parameters

n	Final smoothing iterations.

◆ setFixedIter()

template<typename MF >

void amrex::MLMGT< MF >::setFixedIter ( int nit )

inlinenoexcept

Set the number of fixed MLMG iterations (convergence may still exit early if the residual is already small).

Parameters

nit	Target number of iterations.

◆ setHybridDivergenceFactor()

template<typename MF >

void amrex::MLMGT< MF >::setHybridDivergenceFactor ( RT f )

inlinenoexcept

Hybrid mode: switch to AlgMG when the residual exceeds f times the best residual so far (default 10).

◆ setHybridStallCriterion()

template<typename MF >

void amrex::MLMGT< MF >::setHybridStallCriterion	(	int	window,
		RT	rate
	)

inlinenoexcept

Hybrid mode: switch to AlgMG when the residual has not dropped by rate per iteration on average over the last window iterations (defaults 0.8 and 4).

◆ setMaxFmgIter()

template<typename MF >

void amrex::MLMGT< MF >::setMaxFmgIter ( int n )

inlinenoexcept

Cap the number of FMG cycles executed.

Parameters

n	Maximum FMG cycles per solve.

◆ setMaxIter()

template<typename MF >

void amrex::MLMGT< MF >::setMaxIter ( int n )

inlinenoexcept

Cap the number of MLMG iterations executed.

Parameters

n	Maximum iterations per solve (may include FMG cycles).

◆ setMultigridType()

template<typename MF >

void amrex::MLMGT< MF >::setMultigridType ( MultigridType t )

inlinenoexcept

Select how AMR level 0 is solved. See MultigridType.

◆ setNoGpuSync()

template<typename MF >

void amrex::MLMGT< MF >::setNoGpuSync ( bool do_not_sync )

inlinenoexcept

Control implicit GPU synchronization inside solve().

When enabled, solve() runs in a single-stream region without the implicit stream synchronizations normally performed by MFIter and many amrex functions. The GPU streams are synchronized once when solve() returns, unless the caller is already in a Gpu::NoSyncRegion. This is off by default. Skipping the synchronizations helps small problems with few boxes, but running on a single stream can slow down solvers that launch many small per-box kernels (e.g., the nodal and EB solvers with many boxes per process). Try both settings for your problem.

Parameters

do_not_sync True skips the implicit syncs. Default is false.

◆ setNSolve()

template<typename MF >

void amrex::MLMGT< MF >::setNSolve ( int flag )

inlinenoexcept

Enable (flag!=0) or disable the N-solve path.

Parameters

flag	Nonzero enables N-solve support.

◆ setNSolveGridSize()

template<typename MF >

void amrex::MLMGT< MF >::setNSolveGridSize ( int s )

inlinenoexcept

Set the tile size used for N-solve builds.

Parameters

s	Grid size hint for N-solve.

◆ setPostSmooth()

template<typename MF >

void amrex::MLMGT< MF >::setPostSmooth ( int n )

inlinenoexcept

Number of post-smoothing passes per V-cycle.

Parameters

n	Post-smoothing iterations.

◆ setPrecondIter()

template<typename MF >

void amrex::MLMGT< MF >::setPrecondIter ( int nit )

inlinenoexcept

Set how many MLMG iterations the preconditioner executes per Krylov call (still subject to early-convergence checks).

Parameters

nit	Target number of inner iterations.

◆ setPreSmooth()

template<typename MF >

void amrex::MLMGT< MF >::setPreSmooth ( int n )

inlinenoexcept

Number of pre-smoothing passes per V-cycle.

Parameters

n	Pre-smoothing iterations.

◆ setThrowException()

template<typename MF >

void amrex::MLMGT< MF >::setThrowException ( bool t )

inlinenoexcept

Control behavior when the solve fails to converge or blows up.

Parameters

t	True to throw `MLMGT::error` on failure; false to call `Abort`. `solve()` always returns the composite residual norm regardless of this setting.

◆ setVerbose()

template<typename MF >

void amrex::MLMGT< MF >::setVerbose ( int v )

inlinenoexcept

Set the main solver verbosity (0 silent).

Parameters

v	Verbosity level forwarded to MLMG.

◆ solve() [1/4]

template<typename MF >

template<typename AMF >

auto amrex::MLMGT< MF >::solve	(	const Vector< AMF * > &	a_sol,
		const Vector< AMF const * > &	a_rhs,
		RT	a_tol_rel,
		RT	a_tol_abs,
		const char *	checkpoint_file
	)		-> RT

◆ solve() [2/4]

template<typename MF >

template<typename AMF >

RT amrex::MLMGT< MF >::solve	(	const Vector< AMF * > &	a_sol,
		const Vector< AMF const * > &	a_rhs,
		RT	a_tol_rel,
		RT	a_tol_abs,
		const char *	checkpoint_file = `nullptr`
	)

Solve the multilevel system; optional checkpoint_file is for debugging only.

Parameters

a_sol	Per-level solution `MF` s (overwritten with the answer).
a_rhs	Per-level right-hand sides.
a_tol_rel	Relative residual tolerance.
a_tol_abs	Absolute residual tolerance.
checkpoint_file	Optional checkpoint basename for dumping MLMG state (debug).

Returns: Composite infinity norm of the residual at the end of solve.

◆ solve() [3/4]

template<typename MF >

template<typename AMF >

auto amrex::MLMGT< MF >::solve	(	std::initializer_list< AMF * >	a_sol,
		std::initializer_list< AMF const * >	a_rhs,
		RT	a_tol_rel,
		RT	a_tol_abs,
		const char *	checkpoint_file
	)		-> RT

◆ solve() [4/4]

template<typename MF >

template<typename AMF >

RT amrex::MLMGT< MF >::solve	(	std::initializer_list< AMF * >	a_sol,
		std::initializer_list< AMF const * >	a_rhs,
		RT	a_tol_rel,
		RT	a_tol_abs,
		const char *	checkpoint_file = `nullptr`
	)

Convenience initializer-list overload that forwards to the Vector-based solve.

Parameters

a_sol	Initializer list converted to a temporary Vector.
a_rhs	Initializer list converted to a temporary Vector.
a_tol_rel	Relative residual tolerance.
a_tol_abs	Absolute residual tolerance.
checkpoint_file	Optional checkpoint basename for dumping MLMG state (debug).

Returns: Composite infinity norm of the residual at the end of solve.

◆ usedAlgMG()

template<typename MF >

bool amrex::MLMGT< MF >::usedAlgMG ( ) const

inlinenoexcept

Whether the last solve used AlgMG on AMR level 0 (always in the algebraic type, after the switch in the hybrid type).

Friends And Related Symbol Documentation

◆ GMRESMLMGT

template<typename MF >

template<typename M >

friend class GMRESMLMGT

friend

◆ MLCGSolverT

template<typename MF >

template<typename T >

friend class MLCGSolverT

friend

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

/home/runner/work/amrex/amrex/Src/LinearSolvers/MLMG/AMReX_MLLinOp.H
/home/runner/work/amrex/amrex/Src/LinearSolvers/MLMG/AMReX_MLMG.H

Classes

Public Types

Public Member Functions

Friends

Member Typedef Documentation

◆ BCMode

◆ BottomSolver

◆ FAB

◆ Location

◆ MFType

◆ MultigridType

◆ RT

Member Enumeration Documentation

◆ CFStrategy

Constructor & Destructor Documentation

◆ MLMGT() [1/3]

◆ ~MLMGT()

◆ MLMGT() [2/3]

◆ MLMGT() [3/3]

Member Function Documentation

◆ actualBottomSolve()

◆ addInterpCorrection()

◆ algmgLevel0Solve()

◆ algmgSolve()

◆ apply()

◆ applyPrecond()

◆ bottomSolve()

◆ bottomSolveWithAlgMG()

◆ bottomSolveWithCG()

◆ compResidual()

◆ computeMLResidual()

◆ computeResidual()

◆ computeResOfCorrection()

◆ computeResWithCrseCorFineCor()

◆ computeResWithCrseSolFineCor()

◆ configureAlgMG()

◆ decPrintIdentation()

◆ getBottomSolver()

◆ getBottomToleranceAbs()

◆ getBottomVerbose()

◆ getEBFluxes() [1/2]

◆ getEBFluxes() [2/2]

◆ getFinalResidual()

◆ getFluxes() [1/8]

◆ getFluxes() [2/8]

◆ getFluxes() [3/8]

◆ getFluxes() [4/8]

◆ getFluxes() [5/8]

◆ getFluxes() [6/8]

◆ getFluxes() [7/8]

◆ getFluxes() [8/8]

◆ getGradSolution() [1/2]

◆ getGradSolution() [2/2]

◆ getInitResidual()

◆ getInitRHS()

◆ getLinOp()

◆ getMultigridType()

◆ getNumCGIters()

◆ getNumIters()

◆ getResidualHistory()

◆ getVerbose()

◆ hybridShouldSwitch()

◆ incPrintIdentation()

◆ interpCorrection() [1/2]

◆ interpCorrection() [2/2]

◆ makeSolvable() [1/2]

◆ makeSolvable() [2/2]

◆ mgFcycle()

◆ mgVcycle()

◆ miniCycle()

◆ MLResNormInf()

◆ MLRhsNormInf()

◆ NSolve()

◆ numAMRLevels()

◆ oneIter()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ postCG()

◆ precond()

◆ prepareForFluxes()