#include <fft_grid_sticks.hpp>

Inheritance diagram for q3::FFTGridSticks:

Public Member Functions
	FFTGridSticks (const FFTGridSticks &)=delete

	FFTGridSticks (MPI_Comm communicator)

	~FFTGridSticks () override

void	assign_sticks (const std::vector< int > &stick_weights) override

bool	co_locates_mirrors () const override

void	execute_forward_on_buffers () const override

void	execute_inverse_raw_on_buffers () const override

void	forward (Complex *data) const override

int	g_vector_to_fft_grid_index (int miller_1, int miller_2, int miller_3) const override

void	gather_local_g_space (const Complex full_g_space, Complex local_g_space) const override

int	global_real_space_index (int local_index) const override
	Local real space is [plane][i1][i2], the plane counted from local_offset().

int	grid_dimension_1 () const override

int	grid_dimension_2 () const override

int	grid_dimension_3 () const override

void	init (int dimension_1, int dimension_2, int dimension_3, bool use_measured_planning=false) override

Complex *	input_buffer () const override

void	inverse (Complex *data) const override

void	inverse_raw (Complex *data) const override

int	local_g_space_points () const override

int	local_grid_points () const override

int	local_offset () const override
	First plane along the third dimension held here.

int	local_sticks () const

FFTGridSticks &	operator= (const FFTGridSticks &)=delete

Complex *	output_buffer () const override

bool	owns_stick (int miller_1, int miller_2) const override

const FFTStickPartition &	partition () const

void	prepare_forward_from_output () const override
	The forward transform consumes the plane buffer directly.

void	reduce_g_space (Complex *data, int number_of_elements) const override

void	scatter_local_g_space (const Complex local_g_space, Complex full_g_space) const override
	The reverse: place this rank's reciprocal-space points into a full array.

int	slab_dimension_1 () const override
	No restriction along the first dimension: ownership is by stick.

int	total_grid_points () const override

Public Member Functions inherited from q3::FFTGrid
virtual	~FFTGrid ()=default

virtual int	concurrent_transform_slots () const

virtual void	execute_forward_on_slot (int) const
	Forward transform on slot `slot`, the slot-aware `execute_forward_on_buffers()`.

virtual void	execute_inverse_raw_on_slot (int) const
	Inverse transform on slot `slot`, the slot-aware `execute_inverse_raw_on_buffers()`.

virtual void	forward_batched (Complex *data, int batch_size) const

virtual void	initialize_batched_plans (int, bool=false) const

virtual int	initialized_batched_plan_size () const

virtual void	inverse_raw_batched (Complex *data, int batch_size) const

virtual void	inverse_raw_on_slot (Complex *data, int) const

virtual void	prepare_forward_from_output_on_slot (int) const
	Output-to-input copy on slot `slot`, the slot-aware `prepare_forward_from_output()`.

virtual Complex *	slot_input_buffer (int) const

virtual Complex *	slot_output_buffer (int) const

Detailed Description

Definition at line 56 of file fft_grid_sticks.hpp.

Constructor & Destructor Documentation

◆ FFTGridSticks() [1/2]

q3::FFTGridSticks::FFTGridSticks ( MPI_Comm communicator )

inlineexplicit

Definition at line 58 of file fft_grid_sticks.hpp.

◆ ~FFTGridSticks()

q3::FFTGridSticks::~FFTGridSticks ( )

inlineoverride

Definition at line 63 of file fft_grid_sticks.hpp.

◆ FFTGridSticks() [2/2]

q3::FFTGridSticks::FFTGridSticks ( const FFTGridSticks & )

delete

Member Function Documentation

◆ assign_sticks()

void q3::FFTGridSticks::assign_sticks ( const std::vector< int > & stick_weights )

inlineoverridevirtual

Assign sticks to ranks from a weight per stick – the number of G-vectors on it inside the cutoff, zero for an empty stick – and rebuild the communication plan and the FFTW plans to match.

Every rank enumerates every rank's sticks in the same order, so the transpose can be unpacked without exchanging index lists.

All-to-all counts. Rank r sends, to rank q, the plane range of q for each of r's sticks; it receives from q the plane range of r for each of q's sticks.

Reimplemented from q3::FFTGrid.

Definition at line 115 of file fft_grid_sticks.hpp.

References q3::FFTStickPartition::build(), q3::FFTStickPartition::owner_of(), and q3::FFTStickPartition::unassigned.

Referenced by init().

◆ co_locates_mirrors()

bool q3::FFTGridSticks::co_locates_mirrors ( ) const

inlineoverridevirtual

Whether a G-vector and its negative are always held by the same rank. True for a serial grid and for the stick layout; false for slabs, which is what forced the gamma-only path off under MPI.

Reimplemented from q3::FFTGrid.

Definition at line 228 of file fft_grid_sticks.hpp.

◆ execute_forward_on_buffers()

void q3::FFTGridSticks::execute_forward_on_buffers ( ) const

inlineoverridevirtual

The interface promises the result of any transform in output_buffer(). The forward transform lands in the stick buffer, so it is copied across – one memcpy of the G-space count, the same order as the transpose pack – rather than making every consumer learn which buffer to read.

Implements q3::FFTGrid.

Definition at line 286 of file fft_grid_sticks.hpp.

◆ execute_inverse_raw_on_buffers()

void q3::FFTGridSticks::execute_inverse_raw_on_buffers ( ) const

inlineoverridevirtual

Execute a raw inverse FFT on the internal buffers (no copy, no normalization).

Caller must have populated input_buffer() before calling. Result is available in output_buffer() after this call.

Implements q3::FFTGrid.

Definition at line 276 of file fft_grid_sticks.hpp.

◆ forward()

void q3::FFTGridSticks::forward ( Complex * data ) const

inlineoverridevirtual

Forward FFT: real-space -> reciprocal-space (unnormalized).

Implements q3::FFTGrid.

Definition at line 298 of file fft_grid_sticks.hpp.

◆ g_vector_to_fft_grid_index()

int q3::FFTGridSticks::g_vector_to_fft_grid_index	(	int	miller_1,
		int	miller_2,
		int	miller_3
	)		const

inlineoverridevirtual

Map a G-vector (integer Miller indices) to FFT array index. Handles negative indices via wrapping.

Implements q3::FFTGrid.

Definition at line 255 of file fft_grid_sticks.hpp.

References q3::FFTStickPartition::wrap().

◆ gather_local_g_space()

void q3::FFTGridSticks::gather_local_g_space	(	const Complex *	full_g_space,
		Complex *	local_g_space
	)		const

inlineoverridevirtual

Copy this rank's reciprocal-space points out of a full, replicated G-space array laid out [i1][i2][i3], into the local G-space layout. The slab layout is a contiguous run at local_offset(); the stick layout is not, so consumers must go through this rather than a memcpy.

Reimplemented from q3::FFTGrid.

Definition at line 232 of file fft_grid_sticks.hpp.

◆ global_real_space_index()

int q3::FFTGridSticks::global_real_space_index ( int local_index ) const

inlineoverridevirtual

Local real space is [plane][i1][i2], the plane counted from local_offset().

Reimplemented from q3::FFTGrid.

Definition at line 209 of file fft_grid_sticks.hpp.

◆ grid_dimension_1()

int q3::FFTGridSticks::grid_dimension_1 ( ) const

inlineoverridevirtual

Grid size along the first dimension.

Implements q3::FFTGrid.

Definition at line 186 of file fft_grid_sticks.hpp.

◆ grid_dimension_2()

int q3::FFTGridSticks::grid_dimension_2 ( ) const

inlineoverridevirtual

Grid size along the second dimension.

Implements q3::FFTGrid.

Definition at line 189 of file fft_grid_sticks.hpp.

◆ grid_dimension_3()

int q3::FFTGridSticks::grid_dimension_3 ( ) const

inlineoverridevirtual

Grid size along the third dimension.

Implements q3::FFTGrid.

Definition at line 192 of file fft_grid_sticks.hpp.

◆ init()

void q3::FFTGridSticks::init	(	int	dimension_1,
		int	dimension_2,
		int	dimension_3,
		bool	use_measured_planning = `false`
	)

inlineoverridevirtual

Size the grid and, until told otherwise, treat every stick as occupied. assign_sticks() narrows that to the sticks inside a cutoff once the basis knows which those are.

Planes along the third dimension, contiguous ranges, the remainder spread one plane at a time over the lowest ranks.

Implements q3::FFTGrid.

Definition at line 75 of file fft_grid_sticks.hpp.

References assign_sticks().

◆ input_buffer()

Complex * q3::FFTGridSticks::input_buffer ( ) const

inlineoverridevirtual

Access the FFT grid's internal input buffer for zero-copy transforms.

Callers scatter G-space data directly into this buffer, then call execute_inverse_raw_on_buffers() to transform in-place. This eliminates the memcpy overhead of inverse_raw() / forward().

The buffer has at least local_grid_points() elements of usable space.

Implements q3::FFTGrid.

Definition at line 269 of file fft_grid_sticks.hpp.

◆ inverse()

void q3::FFTGridSticks::inverse ( Complex * data ) const

inlineoverridevirtual

Inverse FFT: reciprocal-space -> real-space (includes 1/N normalization).

Implements q3::FFTGrid.

Definition at line 310 of file fft_grid_sticks.hpp.

References inverse_raw().

◆ inverse_raw()

void q3::FFTGridSticks::inverse_raw ( Complex * data ) const

inlineoverridevirtual

Inverse FFT without 1/N normalization (raw FFTW backward).

Implements q3::FFTGrid.

Definition at line 304 of file fft_grid_sticks.hpp.

Referenced by inverse().

◆ local_g_space_points()

int q3::FFTGridSticks::local_g_space_points ( ) const

inlineoverridevirtual

Number of reciprocal-space points this rank holds.

Equal to local_grid_points() for every layout in which G-space and real space share a buffer. The stick decomposition holds G-space as whole sticks and real space as whole planes, so the two counts differ, and a caller sizing a G-space scatter must ask this rather than assume.

Reimplemented from q3::FFTGrid.

Definition at line 201 of file fft_grid_sticks.hpp.

◆ local_grid_points()

int q3::FFTGridSticks::local_grid_points ( ) const

inlineoverridevirtual

Number of real-space grid points stored on the local rank.

Implements q3::FFTGrid.

Definition at line 198 of file fft_grid_sticks.hpp.

◆ local_offset()

int q3::FFTGridSticks::local_offset ( ) const

inlineoverridevirtual

First plane along the third dimension held here.

Implements q3::FFTGrid.

Definition at line 205 of file fft_grid_sticks.hpp.

◆ local_sticks()

int q3::FFTGridSticks::local_sticks ( ) const

inline

Definition at line 221 of file fft_grid_sticks.hpp.

◆ operator=()

FFTGridSticks & q3::FFTGridSticks::operator= ( const FFTGridSticks & )

delete

◆ output_buffer()

Complex * q3::FFTGridSticks::output_buffer ( ) const

inlineoverridevirtual

Access the FFT grid's internal output buffer for zero-copy transforms.

After execute_inverse_raw_on_buffers(), real-space data is here. After execute_forward_on_buffers(), G-space data is here.

For in-place plans (MPI FFT), this returns the same pointer as input_buffer(). For out-of-place plans (Serial FFT), this is a separate buffer.

Implements q3::FFTGrid.

Definition at line 272 of file fft_grid_sticks.hpp.

◆ owns_stick()

bool q3::FFTGridSticks::owns_stick	(	int	,
		int
	)		const

inlineoverridevirtual

Whether this rank holds the G-vectors sharing the first two Miller indices. True everywhere for a layout that does not distribute G-space by stick; the plane-wave selector asks this to decide what to keep.

Reimplemented from q3::FFTGrid.

Definition at line 250 of file fft_grid_sticks.hpp.

References q3::FFTStickPartition::owner_of_miller().

◆ partition()

const FFTStickPartition & q3::FFTGridSticks::partition ( ) const

inline

Definition at line 224 of file fft_grid_sticks.hpp.

◆ prepare_forward_from_output()

void q3::FFTGridSticks::prepare_forward_from_output ( ) const

inlineoverridevirtual

The forward transform consumes the plane buffer directly.

Implements q3::FFTGrid.

Definition at line 294 of file fft_grid_sticks.hpp.

◆ reduce_g_space()

void q3::FFTGridSticks::reduce_g_space	(	Complex *	data,
		int	number_of_elements
	)		const

inlineoverridevirtual

Reduce G-space data across the pool to make it redundant on all ranks.

Serial: no-op. MPI: MPI_Allreduce(MPI_IN_PLACE, ..., MPI_SUM, pool_comm).

Implements q3::FFTGrid.

Definition at line 318 of file fft_grid_sticks.hpp.

◆ scatter_local_g_space()

void q3::FFTGridSticks::scatter_local_g_space	(	const Complex *	local_g_space,
		Complex *	full_g_space
	)		const

inlineoverridevirtual

The reverse: place this rank's reciprocal-space points into a full array.

Reimplemented from q3::FFTGrid.

Definition at line 241 of file fft_grid_sticks.hpp.

◆ slab_dimension_1()

int q3::FFTGridSticks::slab_dimension_1 ( ) const

inlineoverridevirtual

No restriction along the first dimension: ownership is by stick.

Reimplemented from q3::FFTGrid.

Definition at line 218 of file fft_grid_sticks.hpp.

◆ total_grid_points()

int q3::FFTGridSticks::total_grid_points ( ) const

inlineoverridevirtual

Total number of real-space grid points across all processes.

Implements q3::FFTGrid.

Definition at line 195 of file fft_grid_sticks.hpp.

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

src/layer_3_representation/basis/planewave/internal/fft/fft_grid_sticks.hpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ FFTGridSticks() [1/2]

◆ ~FFTGridSticks()

◆ FFTGridSticks() [2/2]

Member Function Documentation

◆ assign_sticks()

◆ co_locates_mirrors()

◆ execute_forward_on_buffers()

◆ execute_inverse_raw_on_buffers()

◆ forward()

◆ g_vector_to_fft_grid_index()

◆ gather_local_g_space()

◆ global_real_space_index()

◆ grid_dimension_1()

◆ grid_dimension_2()

◆ grid_dimension_3()

◆ init()

◆ input_buffer()

◆ inverse()

◆ inverse_raw()

◆ local_g_space_points()

◆ local_grid_points()

◆ local_offset()

◆ local_sticks()

◆ operator=()

◆ output_buffer()

◆ owns_stick()

◆ partition()

◆ prepare_forward_from_output()

◆ reduce_g_space()

◆ scatter_local_g_space()

◆ slab_dimension_1()

◆ total_grid_points()