1-dimensional distributed FFT plan with RAII semantics. More...

#include <shafft.hpp>

Public Member Functions
	FFT1D () noexcept=default
	Default constructor (uninitialized).

	~FFT1D () noexcept override
	Destructor.

void	release () noexcept override
	Release all internal resources.

	FFT1D (FFT1D &&other) noexcept
	Move constructor.

FFT1D &	operator= (FFT1D &&other) noexcept
	Move assignment operator.

	FFT1D (const FFT1D &)=delete

FFT1D &	operator= (const FFT1D &)=delete

int	init (size_t globalN, size_t localN, size_t localStart, FFTType precision, MPI_Comm comm) noexcept
	Initialize plan.

int	plan () noexcept override
	Create backend FFT plans.

int	setBuffers (complexf data, complexf work) noexcept
	Attach data and work buffers.

int	setBuffers (complexd data, complexd work) noexcept

int	getBuffers (complexf data, complexf work) noexcept
	Retrieve current buffer pointers.

int	getBuffers (complexd data, complexd work) noexcept
	Retrieve current buffer pointers (double precision).

int	execute (FFTDirection direction) noexcept override
	Execute the transform.

int	normalize () noexcept override
	Apply symmetric normalization (1/sqrt(N) per transform).

std::vector< size_t >	globalShape () const noexcept
	Get global shape as length-1 vector.

size_t	globalSize () const noexcept override
	Get global FFT size.

int	ndim () const noexcept override
	Get number of dimensions (always 1).

FFTType	fftType () const noexcept override
	Get FFT precision (C2C or Z2Z).

size_t	localSize () const noexcept
	Get local element count (before padding).

size_t	allocSize () const noexcept override
	Get required buffer size in complex elements.

int	getLayout (std::vector< size_t > &localShape, std::vector< size_t > &offset, TensorLayout layout=TensorLayout::CURRENT) const noexcept
	Query local layout.

int	getAxes (std::vector< int > &ca, std::vector< int > &da, TensorLayout layout=TensorLayout::CURRENT) const noexcept
	Query axis distribution.

bool	isActive () const noexcept override
	Check if this rank participates in computation.

int	setBuffersRaw (void data, void work) noexcept override
	Attach buffers (type-erased).

int	getBuffersRaw (void data, void work) noexcept override
	Retrieve current buffer pointers (type-erased).

int	getCommunicator (MPI_Comm *outComm) const noexcept
	Get a duplicated communicator from this plan.

int	init (shafft_1d_config_t &cfg) noexcept
	Initialize plan from a resolved 1-D config object.

Public Member Functions inherited from shafft::FFT
	operator bool () const noexcept
	Check if the plan is valid (alias for isConfigured).

PlanState	state () const noexcept
	Get the current plan state.

bool	isConfigured () const noexcept
	Check if the plan is at least configured (init() succeeded).

bool	isPlanned () const noexcept
	Check if the plan is fully planned and ready for execution.

	FFT (const FFT &)=delete

FFT &	operator= (const FFT &)=delete

Detailed Description

Uses block distribution: rank r owns [localStart, localStart + localN). allocSize() may exceed localN due to padding.

Note

Typical usage flow:

Call configuration1D() to compute local layout
Construct FFT1D and call init() with the computed parameters
Allocate buffers using allocSize() and call setBuffers()
Call plan() to create backend FFT plans
Call execute() for forward/backward transforms
Call normalize() after a forward-backward pair to restore scale

Examples: example_FFT1D.cpp.

Constructor & Destructor Documentation

◆ FFT1D() [1/3]

shafft::FFT1D::FFT1D ( )

defaultnoexcept

◆ ~FFT1D()

shafft::FFT1D::~FFT1D ( )

overridenoexcept

◆ FFT1D() [2/3]

shafft::FFT1D::FFT1D ( FFT1D && other )

noexcept

Transfers ownership of backend resources from other. The moved-from plan becomes uninitialized.

Parameters

other Plan to move from.

◆ FFT1D() [3/3]

shafft::FFT1D::FFT1D ( const FFT1D & )

delete

Member Function Documentation

◆ release()

void shafft::FFT1D::release ( )

overridevirtualnoexcept

Call before MPI_Finalize() if the plan outlives MPI.

Implements shafft::FFT.

Examples: example_FFT1D.cpp.

◆ operator=() [1/2]

FFT1D & shafft::FFT1D::operator= ( FFT1D && other )

noexcept

Releases current resources and takes ownership from other. The moved-from plan becomes uninitialized.

Parameters

other Plan to move from.

Returns: Reference to this plan.

◆ operator=() [2/2]

FFT1D & shafft::FFT1D::operator= ( const FFT1D & )

delete

◆ init() [1/2]

int shafft::FFT1D::init	(	size_t	globalN,
		size_t	localN,
		size_t	localStart,
		FFTType	precision,
		MPI_Comm	comm
	)

noexcept

Call configuration1D() first to compute layout parameters.

Parameters

globalN	Global FFT size.
localN	Local element count for this rank.
localStart	This rank's offset in global array.
precision	FFT precision (C2C or Z2Z).
comm	MPI communicator.

Returns: 0 on success, non-zero on error.

Examples: example_FFT1D.cpp.

◆ plan()

int shafft::FFT1D::plan ( )

overridevirtualnoexcept

Must be called after init(). For FFTW, buffers may be set later; dummy buffers are used for planning. Calling plan() more than once is an error.

Returns: 0 on success, non-zero on error.

Implements shafft::FFT.

Examples: example_FFT1D.cpp.

◆ setBuffers() [1/2]

int shafft::FFT1D::setBuffers	(	complexf *	data,
		complexf *	work
	)

noexcept

Buffers must be allocated and have at least allocSize() elements.

Parameters

data	Input buffer (allocSize() elements).
work	Output buffer (allocSize() elements).

Returns: 0 on success, non-zero on error.

Examples: example_FFT1D.cpp.

◆ setBuffers() [2/2]

int shafft::FFT1D::setBuffers	(	complexd *	data,
		complexd *	work
	)

noexcept

◆ getBuffers() [1/2]

int shafft::FFT1D::getBuffers	(	complexf **	data,
		complexf **	work
	)

noexcept

Parameters

[out]	data	Current data buffer.
[out]	work	Current work buffer.

Returns: 0 on success, non-zero on error.

Examples: example_FFT1D.cpp.

◆ getBuffers() [2/2]

int shafft::FFT1D::getBuffers	(	complexd **	data,
		complexd **	work
	)

noexcept

Parameters

[out]	data	Current data buffer.
[out]	work	Current work buffer.

Returns: 0 on success, non-zero on error.

◆ execute()

int shafft::FFT1D::execute ( FFTDirection direction )

overridevirtualnoexcept

Parameters

direction FORWARD or BACKWARD.

Returns: 0 on success, non-zero on error.

Implements shafft::FFT.

Examples: example_FFT1D.cpp.

◆ normalize()

int shafft::FFT1D::normalize ( )

overridevirtualnoexcept

After a forward-backward pair, calling normalize() restores original scale.

Returns: 0 on success, non-zero on error.

Implements shafft::FFT.

Examples: example_FFT1D.cpp.

◆ globalShape()

std::vector< size_t > shafft::FFT1D::globalShape ( ) const

noexcept

◆ globalSize()

size_t shafft::FFT1D::globalSize ( ) const

overridevirtualnoexcept

Implements shafft::FFT.

◆ ndim()

int shafft::FFT1D::ndim ( ) const

overridevirtualnoexcept

Implements shafft::FFT.

◆ fftType()

FFTType shafft::FFT1D::fftType ( ) const

overridevirtualnoexcept

Implements shafft::FFT.

◆ localSize()

size_t shafft::FFT1D::localSize ( ) const

noexcept

Examples: example_FFT1D.cpp.

◆ allocSize()

size_t shafft::FFT1D::allocSize ( ) const

overridevirtualnoexcept

May exceed localSize() due to padding.

Implements shafft::FFT.

Examples: example_FFT1D.cpp.

◆ getLayout()

int shafft::FFT1D::getLayout	(	std::vector< size_t > &	localShape,
		std::vector< size_t > &	offset,
		TensorLayout	layout = `TensorLayout::CURRENT`
	)		const

noexcept

Parameters

[out]	localShape	Local size as length-1 vector.
[out]	offset	Local offset as length-1 vector.
	layout	CURRENT, INITIAL, or REDISTRIBUTED.

Returns: 0 on success, non-zero on error.

◆ getAxes()

int shafft::FFT1D::getAxes	(	std::vector< int > &	ca,
		std::vector< int > &	da,
		TensorLayout	layout = `TensorLayout::CURRENT`
	)		const

noexcept

Returns ca={} and da={0} (the single axis is distributed).

Parameters

[out]	ca	Contiguous axes (empty).
[out]	da	Distributed axes ({0}).
	layout	CURRENT, INITIAL, or REDISTRIBUTED.

Returns: 0 on success, non-zero on error.

◆ isActive()

bool shafft::FFT1D::isActive ( ) const

overridevirtualnoexcept

Implements shafft::FFT.

◆ setBuffersRaw()

int shafft::FFT1D::setBuffersRaw	(	void *	data,
		void *	work
	)

overridevirtualnoexcept

Parameters

data	Data buffer.
work	Work buffer.

Returns: 0 on success, non-zero on error.

Implements shafft::FFT.

◆ getBuffersRaw()

int shafft::FFT1D::getBuffersRaw	(	void **	data,
		void **	work
	)

overridevirtualnoexcept

Parameters

[out]	data	Current data buffer.
[out]	work	Current work buffer.

Returns: 0 on success, non-zero on error.

Implements shafft::FFT.

◆ getCommunicator()

int shafft::FFT1D::getCommunicator ( MPI_Comm * outComm ) const

noexcept

Returns MPI_COMM_NULL for inactive ranks. The caller must call MPI_Comm_free() on the returned communicator when done.

Parameters

[out] outComm Receives duplicated communicator.

Returns: 0 on success, non-zero on error.

◆ init() [2/2]

int shafft::FFT1D::init ( shafft_1d_config_t & cfg )

noexcept

Auto-resolves if SHAFFT_CONFIG_RESOLVED is not set. Communicator is read from the config struct (worldComm).

Parameters

cfg	Config struct (resolved or will be auto-resolved).

Returns: 0 on success, non-zero on error.

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

include/shafft/shafft.hpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ FFT1D() [1/3]

◆ ~FFT1D()

◆ FFT1D() [2/3]

◆ FFT1D() [3/3]

Member Function Documentation

◆ release()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ init() [1/2]

◆ plan()

◆ setBuffers() [1/2]

◆ setBuffers() [2/2]

◆ getBuffers() [1/2]

◆ getBuffers() [2/2]

◆ execute()

◆ normalize()

◆ globalShape()

◆ globalSize()

◆ ndim()

◆ fftType()

◆ localSize()

◆ allocSize()

◆ getLayout()

◆ getAxes()

◆ isActive()

◆ setBuffersRaw()

◆ getBuffersRaw()

◆ getCommunicator()

◆ init() [2/2]