amrex::ChebyshevSmoother< T > Class Template Reference

Chebyshev polynomial smoother for AlgVector/SpMatrix systems. More...

#include <AMReX_Smoother_MV.H>

Public Member Functions
	ChebyshevSmoother (SpMatrix< T > const *a_A, bool a_l1=false)
void	setDegree (int d)
	Polynomial degree (number of matrix-vector products per application, 2 by default).
void	setEigRatio (T r)
int	setNumIters (int a_niters)
	Number of polynomial applications per call (1 by default).
void	setLambdaMax (T l)
	Set the largest eigenvalue of the scaled operator instead of the bound.
T	lambdaMax ()
void	operator() (AlgVector< T > &xvec, AlgVector< T > const &bvec, bool with_initial_guess=false)
	Apply the smoother to solve approximately for xvec.
void	bound ()
	Gershgorin bound of the eigenvalues of D^{-1} A.

Detailed Description

template<typename T>
class amrex::ChebyshevSmoother< T >

Chebyshev polynomial smoother for AlgVector/SpMatrix systems.

Applies a Chebyshev polynomial of the diagonally (or l1) scaled operator D^{-1} A that damps the spectrum in [lambda_max / ratio, lambda_max] [Adams, Brezina, Hu, Tuminaro, J. Comput. Phys. 188 (2003), 593-610]. Each application costs degree matrix-vector products. lambda_max is the Gershgorin bound max_i sum_j |a_ij| / |d_i| of the scaled operator, which is one with l1 scaling.

Constructor & Destructor Documentation

ChebyshevSmoother()

template<typename T>

amrex::ChebyshevSmoother< T >::ChebyshevSmoother ( SpMatrix< T > const * a_A, bool a_l1 = false )

inlineexplicit

Parameters

a_A	Sparse matrix.
a_l1	Use l1 scaling instead of the diagonal.

Member Function Documentation

bound()

template<typename T>

void amrex::ChebyshevSmoother< T >::bound ( )

inline

Gershgorin bound of the eigenvalues of D^{-1} A.

lambdaMax()

template<typename T>

T amrex::ChebyshevSmoother< T >::lambdaMax ( )

inline

Upper bound of the eigenvalues of the scaled operator, computed on first use. The first call is collective.

operator()()

template<typename T>

void amrex::ChebyshevSmoother< T >::operator() ( AlgVector< T > & xvec, AlgVector< T > const & bvec, bool with_initial_guess = false )

inline

Apply the smoother to solve approximately for xvec.

Parameters

xvec	Solution vector updated in place.
bvec	RHS vector.
with_initial_guess	True if xvec already holds an initial guess.

setDegree()

template<typename T>

void amrex::ChebyshevSmoother< T >::setDegree ( int d )

inline

Polynomial degree (number of matrix-vector products per application, 2 by default).

setEigRatio()

template<typename T>

void amrex::ChebyshevSmoother< T >::setEigRatio ( T r )

inline

Ratio between the largest eigenvalue and the lower end of the smoothing interval (20 by default).

setLambdaMax()

template<typename T>

void amrex::ChebyshevSmoother< T >::setLambdaMax ( T l )

inline

Set the largest eigenvalue of the scaled operator instead of the bound.

setNumIters()

template<typename T>

int amrex::ChebyshevSmoother< T >::setNumIters ( int a_niters )

inline

Number of polynomial applications per call (1 by default).

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

• /home/runner/work/amrex/amrex/Src/LinearSolvers/AMReX_Smoother_MV.H