Free functions for C interoperability and advanced use. More...

Classes
struct	shafft::Version
	Library version information. More...

Functions
int	shafft::setBuffers (detail::PlanBase plan, complexf data, complexf *work) noexcept
	Attach buffers using portable complex types.

int	shafft::getBuffers (detail::PlanBase plan, complexf data, complexf *work) noexcept
	Retrieve current buffer pointers.

int	shafft::allocBuffer (size_t count, complexf **buf) noexcept
	Allocate buffer for the current backend.

int	shafft::freeBuffer (complexf *buf) noexcept
	Free buffer allocated with allocBuffer().

int	shafft::copyToBuffer (complexf dst, const complexf src, size_t count) noexcept
	Copy from host to SHAFFT buffer.

int	shafft::copyFromBuffer (complexf dst, const complexf src, size_t count) noexcept
	Copy from SHAFFT buffer to host.

int	shafft::planNDCreate (detail::FFTNDPlan **out)
	Allocate N-D plan object (C-style API).

int	shafft::FFT1DCreate (detail::FFT1DPlan **out)
	Allocate 1-D plan object (C-style API).

int	shafft::configuration1D (size_t globalN, size_t &localN, size_t &localStart, FFTType precision, MPI_Comm comm)
	Compute local layout for 1D distributed FFT.

int	shafft::planND (detail::FFTNDPlan *plan, const std::vector< int > &commDims, const std::vector< size_t > &dimensions, FFTType precision, MPI_Comm comm)
	Initialize N-D plan (C-style API).

int	shafft::destroy (detail::PlanBase **plan)
	Release plan resources and null pointer (C-style API).

int	shafft::getLayout (const detail::PlanBase *plan, std::vector< size_t > &subsize, std::vector< size_t > &offset, TensorLayout layout)
	Query tensor layout (C-style API).

int	shafft::getAxes (const detail::PlanBase *plan, std::vector< int > &ca, std::vector< int > &da, TensorLayout layout)
	Query axis distribution (C-style API).

int	shafft::getAllocSize (const detail::PlanBase *plan, size_t &localAllocSize)
	Get required buffer size in complex elements (C-style API).

int	shafft::execute (detail::PlanBase *plan, FFTDirection direction)
	Execute transform (C-style API).

int	shafft::normalize (detail::PlanBase *plan)
	Apply normalization (C-style API).

const char *	shafft::getBackendName () noexcept
	Get the name of the FFT backend used at compile time.

Version	shafft::getVersion () noexcept
	Get the library version as a struct.

int	shafft::finalize () noexcept
	Finalize library and release backend resources.

Detailed Description

These functions mirror the C API but use C++ types. Use them when:

Interoperating with the C API
Managing plan lifetime manually
Needing finer control over buffer allocation

For most applications, prefer the C++ RAII API instead.

Function Documentation

◆ setBuffers()

int shafft::setBuffers	(	detail::PlanBase *	plan,
		complexf *	data,
		complexf *	work
	)

noexcept

GPU backends require device memory; CPU backends require host memory.

Parameters

plan	Plan handle.
data	Data buffer.
work	Work buffer.

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

◆ getBuffers()

int shafft::getBuffers	(	detail::PlanBase *	plan,
		complexf **	data,
		complexf **	work
	)

noexcept

Buffers may be swapped after execute().

Parameters

	plan	Plan handle.
[out]	data	Current data buffer.
[out]	work	Current work buffer.

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

◆ allocBuffer()

int shafft::allocBuffer	(	size_t	count,
		complexf **	buf
	)

noexcept

Uses hipMalloc on GPU, standard allocation on CPU.

Parameters

	count	Number of complex elements.
[out]	buf	Allocated buffer.

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

Examples: example_FFT1D.cpp, example_portable.cpp, and example_portable_config.cpp.

◆ freeBuffer()

int shafft::freeBuffer ( complexf * buf )

noexcept

Parameters

buf	Buffer to free (nullptr safe).

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

Examples: example_FFT1D.cpp, example_portable.cpp, and example_portable_config.cpp.

◆ copyToBuffer()

int shafft::copyToBuffer	(	complexf *	dst,
		const complexf *	src,
		size_t	count
	)

noexcept

Performs copy to a backend buffer.

Parameters

dst	Destination buffer.
src	Source host memory.
count	Number of complex elements.

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

Examples: example_FFT1D.cpp, example_portable.cpp, and example_portable_config.cpp.

◆ copyFromBuffer()

int shafft::copyFromBuffer	(	complexf *	dst,
		const complexf *	src,
		size_t	count
	)

noexcept

Performs copy from a backend buffer to host memory.

Parameters

dst	Destination host memory.
src	Source buffer.
count	Number of complex elements.

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

Examples: example_FFT1D.cpp, example_portable.cpp, and example_portable_config.cpp.

◆ planNDCreate()

int shafft::planNDCreate ( detail::FFTNDPlan ** out )

Prefer the RAII FFTND class. Release with destroy().

Parameters

[out] out Plan pointer.

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

◆ FFT1DCreate()

int shafft::FFT1DCreate ( detail::FFT1DPlan ** out )

Prefer the RAII FFT1D class. Release with destroy().

Parameters

[out] out Plan pointer.

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

◆ configuration1D()

int shafft::configuration1D	(	size_t	globalN,
		size_t &	localN,
		size_t &	localStart,
		FFTType	precision,
		MPI_Comm	comm
	)

Call before FFT1D::init() to obtain layout parameters.

Parameters

	globalN	Global FFT size.
[out]	localN	Local element count.
[out]	localStart	Local 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.

◆ planND()

int shafft::planND	(	detail::FFTNDPlan *	plan,
		const std::vector< int > &	commDims,
		const std::vector< size_t > &	dimensions,
		FFTType	precision,
		MPI_Comm	comm
	)

Prefer FFTND::init() for RAII interface.

Parameters

plan	Plan from planNDCreate().
commDims	Process grid dimensions.
dimensions	Global tensor dimensions.
precision	FFT precision (C2C or Z2Z).
comm	MPI communicator.

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

◆ destroy()

int shafft::destroy ( detail::PlanBase ** plan )

Does not free user buffers. RAII classes handle this automatically.

Parameters

[in,out] plan Plan pointer; set to nullptr on success.

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

◆ getLayout()

int shafft::getLayout	(	const detail::PlanBase *	plan,
		std::vector< size_t > &	subsize,
		std::vector< size_t > &	offset,
		TensorLayout	layout
	)

Parameters

	plan	Plan handle.
[out]	subsize	Local extent per axis.
[out]	offset	Global offset per axis.
	layout	Layout to query (CURRENT, INITIAL, or REDISTRIBUTED).

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

◆ getAxes()

int shafft::getAxes	(	const detail::PlanBase *	plan,
		std::vector< int > &	ca,
		std::vector< int > &	da,
		TensorLayout	layout
	)

Parameters

	plan	Plan handle.
[out]	ca	Contiguous (non-distributed) axes.
[out]	da	Distributed axes.
	layout	Layout to query (CURRENT, INITIAL, or REDISTRIBUTED).

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

◆ getAllocSize()

int shafft::getAllocSize	(	const detail::PlanBase *	plan,
		size_t &	localAllocSize
	)

Parameters

	plan	Plan handle.
[out]	localAllocSize	Required buffer size in complex elements.

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

◆ execute()

int shafft::execute	(	detail::PlanBase *	plan,
		FFTDirection	direction
	)

Parameters

plan	Plan handle.
direction	FORWARD or BACKWARD.

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

◆ normalize()

int shafft::normalize ( detail::PlanBase * plan )

Parameters

plan	Plan handle.

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

◆ getBackendName()

const char * shafft::getBackendName ( )

inlinenoexcept

Returns: "FFTW" or "hipFFT".

◆ getVersion()

Version shafft::getVersion ( )

inlinenoexcept

Returns: Version with major, minor, and patch fields populated.

◆ finalize()

int shafft::finalize ( )

noexcept

Call after all plans are destroyed, before MPI_Finalize() for FFTW backend. Safe to call multiple times.

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

Classes

Functions

Detailed Description

Function Documentation

◆ setBuffers()

◆ getBuffers()

◆ allocBuffer()

◆ freeBuffer()

◆ copyToBuffer()

◆ copyFromBuffer()

◆ planNDCreate()

◆ FFT1DCreate()

◆ configuration1D()

◆ planND()

◆ destroy()

◆ getLayout()

◆ getAxes()

◆ getAllocSize()

◆ execute()

◆ normalize()

◆ getBackendName()

◆ getVersion()

◆ finalize()