amrex::FFT::LocalR2C< T, D, M > Class Template Reference

Local Discrete Fourier Transform. More...

#include <AMReX_FFT_LocalR2C.H>

Public Member Functions
	LocalR2C (IntVectND< M > const &fft_size, T *p_fwd=nullptr, GpuComplex< T > *p_bwd=nullptr, bool cache_plan=true)
	Constructor.
	~LocalR2C ()
	LocalR2C ()=default
	LocalR2C (LocalR2C &&) noexcept
LocalR2C &	operator= (LocalR2C &&) noexcept
	LocalR2C (LocalR2C const &)=delete
LocalR2C &	operator= (LocalR2C const &)=delete
template<Direction DIR = D, std::enable_if_t< DIR==Direction::forward||DIR==Direction::both, int > = 0>
void	forward (T const *indata, GpuComplex< T > *outdata)
	Forward transform.
void	clear ()
template<Direction DIR = D, std::enable_if_t< DIR==Direction::backward||DIR==Direction::both, int > = 0>
void	backward (GpuComplex< T > const *indata, T *outdata)
	Backward transform.
T	scalingFactor () const
IntVectND< M > const &	spectralSize () const
	Spectral domain size.

Private Attributes
Plan< T >	m_fft_fwd
Plan< T >	m_fft_bwd
T *	m_p_fwd = nullptr
GpuComplex< T > *	m_p_bwd = nullptr
IntVectND< M >	m_real_size
IntVectND< M >	m_spectral_size
bool	m_cache_plan = false

Detailed Description

template<typename T, FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>
class amrex::FFT::LocalR2C< T, D, M >

Local Discrete Fourier Transform.

This class supports Fourier transforms between real and complex data. The name R2C indicates that the forward transform converts real data to complex data, while the backward transform converts complex data to real data. It should be noted that both directions of transformation are supported, not just from real to complex. The scaling follows the FFTW convention, where applying the forward transform followed by the backward transform scales the original data by the size of the input array.

For more details, we refer the users to https://amrex-codes.github.io/amrex/docs_html/FFT_Chapter.html.

Constructor & Destructor Documentation

LocalR2C() [1/4]

template<typename T , FFT::Direction D, int M>

amrex::FFT::LocalR2C< T, D, M >::LocalR2C ( IntVectND< M > const &  fft_size, T *  p_fwd = nullptr, GpuComplex< T > *  p_bwd = nullptr, bool  cache_plan = true  )

explicit

Constructor.

Given the diverse interfaces of FFT libraries we use, this constructo has a number of optional arguments.

The user can provide the data pointers to the constructor. They are only needed by FFTW because its plan creation requires the input and output arrays. If they are null, we will delay the plan creation for FFTW until the forward or backward function is called.

The cache_plan option is only used when we use cufft, rocfft and onemkl, but not FFTW.

Parameters

fft_size	The forward domain size (i.e., the domain of the real data)
p_fwd	Forward domain data pointer (optional)
p_bwd	Backward domain data pointer (optional)
cache_plan	Try to cache the plan or not (optionl)

~LocalR2C()

template<typename T , FFT::Direction D, int M>

amrex::FFT::LocalR2C< T, D, M >::~LocalR2C

(

)

LocalR2C() [2/4]

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

amrex::FFT::LocalR2C< T, D, M >::LocalR2C ( )

default

LocalR2C() [3/4]

template<typename T , FFT::Direction D, int M>

amrex::FFT::LocalR2C< T, D, M >::LocalR2C ( LocalR2C< T, D, M > &&  rhs )

noexcept

LocalR2C() [4/4]

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

amrex::FFT::LocalR2C< T, D, M >::LocalR2C ( LocalR2C< T, D, M > const &  )

delete

Member Function Documentation

backward()

template<typename T , FFT::Direction D, int M>

template<Direction DIR, std::enable_if_t< DIR==Direction::backward||DIR==Direction::both, int > >

void amrex::FFT::LocalR2C< T, D, M >::backward	(	GpuComplex< T > const *	indata,
		T *	outdata
	)

Backward transform.

This function is not available when this class template is instantiated for forward-only transform. For GPUs, this function is synchronous on the host.

Parameters

indata	input data
outdata	output data

clear()

template<typename T , FFT::Direction D, int M>

void amrex::FFT::LocalR2C< T, D, M >::clear

(

)

forward()

template<typename T , FFT::Direction D, int M>

template<Direction DIR, std::enable_if_t< DIR==Direction::forward||DIR==Direction::both, int > >

void amrex::FFT::LocalR2C< T, D, M >::forward	(	T const *	indata,
		GpuComplex< T > *	outdata
	)

Forward transform.

This function is not available when this class template is instantiated for backward-only transform. For GPUs, this function is synchronous on the host.

Parameters

indata	input data
outdata	output data

operator=() [1/2]

template<typename T , FFT::Direction D, int M>

LocalR2C< T, D, M > & amrex::FFT::LocalR2C< T, D, M >::operator= ( LocalR2C< T, D, M > &&  rhs )

noexcept

operator=() [2/2]

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

LocalR2C & amrex::FFT::LocalR2C< T, D, M >::operator= ( LocalR2C< T, D, M > const &  )

delete

scalingFactor()

template<typename T , FFT::Direction D, int M>

T amrex::FFT::LocalR2C< T, D, M >::scalingFactor

(

)

const

Scaling factor. If the data goes through forward and then backward, the result multiplied by the scaling factor is equal to the original data.

spectralSize()

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

IntVectND< M > const & amrex::FFT::LocalR2C< T, D, M >::spectralSize ( ) const

inline

Spectral domain size.

Member Data Documentation

m_cache_plan

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

bool amrex::FFT::LocalR2C< T, D, M >::m_cache_plan = false

private

m_fft_bwd

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

Plan<T> amrex::FFT::LocalR2C< T, D, M >::m_fft_bwd

private

m_fft_fwd

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

Plan<T> amrex::FFT::LocalR2C< T, D, M >::m_fft_fwd

private

m_p_bwd

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

GpuComplex<T>* amrex::FFT::LocalR2C< T, D, M >::m_p_bwd = nullptr

private

m_p_fwd

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

T* amrex::FFT::LocalR2C< T, D, M >::m_p_fwd = nullptr

private

m_real_size

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

IntVectND<M> amrex::FFT::LocalR2C< T, D, M >::m_real_size

private

m_spectral_size

template<typename T , FFT::Direction D = FFT::Direction::both, int M = AMREX_SPACEDIM>

IntVectND<M> amrex::FFT::LocalR2C< T, D, M >::m_spectral_size

private

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

• /home/runner/work/amrex/amrex/Src/FFT/AMReX_FFT_LocalR2C.H