amrex::FFT::OpenBCSolver< T > Class Template Reference

Convolution-based solver for open boundary conditions using Green's functions. More...

#include <AMReX_FFT_OpenBCSolver.H>

Public Types
using	MF = typename R2C< T >::MF
using	cMF = typename R2C< T >::cMF

Public Member Functions
	OpenBCSolver (Box const &domain, Info const &info=Info{})
	Build a solver over domain using the FFT Info settings in info.
template<class F >
void	setGreensFunction (F const &greens_function)
	Populate the spectral Green's function used by subsequent solves.
void	solve (MF &phi, MF const &rho)
	Solve for phi given right-hand side rho.
Box const &	Domain () const
	Access the physical domain this solver was built for.
IntVect const &	PaddedLength () const
	Access the one-sided padded length used to build the internal FFT domain.
cMF &	greensFunctionFFT () noexcept
	Access the spectral Green's function held by this solver.
cMF const &	greensFunctionFFT () const noexcept
	Access the spectral Green's function held by this solver.

Detailed Description

template<typename T = Real>
class amrex::FFT::OpenBCSolver< T >

Convolution-based solver for open boundary conditions using Green's functions.

The class wraps an internal R2C plan and multiplies spectral data by a user-provided Green's function to solve Laplace/Poisson problems on a rectangular domain. It currently solves one right-hand-side component per call; the supplied FFT::Info must have batch_size == 1.

Member Typedef Documentation

cMF

template<typename T = Real>

using amrex::FFT::OpenBCSolver< T >::cMF = typename R2C<T>::cMF

MF

template<typename T = Real>

using amrex::FFT::OpenBCSolver< T >::MF = typename R2C<T>::MF

Constructor & Destructor Documentation

OpenBCSolver()

template<typename T >

amrex::FFT::OpenBCSolver< T >::OpenBCSolver ( Box const &  domain, Info const &  info = Info{}  )

explicit

Build a solver over domain using the FFT Info settings in info.

Parameters

domain	Physical domain (cell or nodal indexing).
info	Optional FFT configuration. Batched solves are not supported.

Member Function Documentation

Domain()

template<typename T = Real>

Box const & amrex::FFT::OpenBCSolver< T >::Domain ( ) const

inline

Access the physical domain this solver was built for.

Returns

Original (un-extended) problem domain.

greensFunctionFFT() [1/2]

template<typename T = Real>

cMF const & amrex::FFT::OpenBCSolver< T >::greensFunctionFFT ( ) const

inlinenoexcept

Access the spectral Green's function held by this solver.

Returns

The spectral Green's function.

greensFunctionFFT() [2/2]

template<typename T = Real>

cMF & amrex::FFT::OpenBCSolver< T >::greensFunctionFFT ( )

inlinenoexcept

Access the spectral Green's function held by this solver.

This lets a caller keep its own set of Green's functions and move them into and out of the solver, for instance with std::swap, instead of recomputing them with setGreensFunction(). Since solve() only reads the spectral Green's function, one moved in this way needs no further preparation.

Note

In 2D, this is an alias of the Green's function R2C's spectral data. Callers may write through it, but must not swap or otherwise re-seat it, because a later setGreensFunction() writes into the aliased array.

Returns

The spectral Green's function.

PaddedLength()

template<typename T = Real>

IntVect const & amrex::FFT::OpenBCSolver< T >::PaddedLength ( ) const

inline

Access the one-sided padded length used to build the internal FFT domain.

Returns

Padded length before the open-boundary convolution domain is doubled.

setGreensFunction()

template<typename T >

template<class F >

void amrex::FFT::OpenBCSolver< T >::setGreensFunction

(

F const &

greens_function

)

Populate the spectral Green's function used by subsequent solves.

Template Parameters

F	Callable type satisfying T(int i, int j, int k).

Parameters

greens_function

Functor that evaluates the physical-space Green's function.

solve()

template<typename T >

void amrex::FFT::OpenBCSolver< T >::solve	(	MF &	phi,
		MF const &	rho
	)

Solve for phi given right-hand side rho.

Parameters

phi	Solution MultiFab (overwritten in place).
rho	Right-hand-side MultiFab.

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

• /home/runner/work/amrex/amrex/Src/FFT/AMReX_FFT_OpenBCSolver.H