Pscf::Prdc::Cuda::FFTBatched< D > Class Template Reference

Batched Fourier transform wrapper for real data. More...

#include <FFTBatched.h>

Public Member Functions
	FFTBatched ()
	Default constructor.
virtual	~FFTBatched ()
	Destructor.
void	setup (IntVec< D > const &meshDimensions, int batchSize)
	Set up FFT calculation (get grid dimensions and make FFT plan)
void	forwardTransform (DeviceArray< cudaReal > const &rFields, DeviceArray< cudaComplex > &kFields) const
	Compute batched forward (real-to-complex) DFTs.
void	inverseTransformUnsafe (DeviceArray< cudaComplex > &kFields, DeviceArray< cudaReal > &rFields) const
	Compute inverse (complex-to-real) Fourier transform.
const IntVec< D > &	meshDimensions () const
	Return the dimensions of the grid for which this was allocated.
void	resetBatchSize (int batchSize)
	Set the batch size to a new value.
bool	isSetup () const
	Has the setup method been called?

Detailed Description

template<int D>
class Pscf::Prdc::Cuda::FFTBatched< D >

Batched Fourier transform wrapper for real data.

Definition at line 31 of file FFTBatched.h.

Constructor & Destructor Documentation

FFTBatched()

template<int D>

Pscf::Prdc::Cuda::FFTBatched< D >::FFTBatched

(

)

Default constructor.

Definition at line 66 of file FFTBatched.tpp.

~FFTBatched()

template<int D>

Pscf::Prdc::Cuda::FFTBatched< D >::~FFTBatched ( )

virtual

Destructor.

Definition at line 80 of file FFTBatched.tpp.

Member Function Documentation

setup()

template<int D>

void Pscf::Prdc::Cuda::FFTBatched< D >::setup	(	IntVec< D > const &	meshDimensions,
		int	batchSize )

Set up FFT calculation (get grid dimensions and make FFT plan)

Parameters

meshDimensions	dimensions of real-space grid
batchSize	number of simultaneous FFTs to perform

Definition at line 94 of file FFTBatched.tpp.

References UTIL_CHECK.

forwardTransform()

template<int D>

void Pscf::Prdc::Cuda::FFTBatched< D >::forwardTransform	(	DeviceArray< cudaReal > const &	rFields,
		DeviceArray< cudaComplex > &	kFields ) const

Compute batched forward (real-to-complex) DFTs.

The resulting complex array is the output of cuFFT's batched forward transform method scaled by a factor of 1/N (where N is the number of grid points). The scaling ensures that a round-trip Fourier transform (forward + inverse) reproduces the original input array.

The number of Fourier transforms performed per batch is pre-set by the setup() method.

This transform is inherently "safe", meaning that the input array will not be modified during the DFT.

Parameters

rFields	real values on r-grid (input, gpu mem)
kFields	complex values on k-grid (output, gpu mem)

Definition at line 191 of file FFTBatched.tpp.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::Prdc::Cuda::VecOp::mulEqS(), UTIL_CHECK, and UTIL_THROW.

inverseTransformUnsafe()

template<int D>

void Pscf::Prdc::Cuda::FFTBatched< D >::inverseTransformUnsafe	(	DeviceArray< cudaComplex > &	kFields,
		DeviceArray< cudaReal > &	rFields ) const

Compute inverse (complex-to-real) Fourier transform.

The resulting real array is the unaltered output of cuFFT's inverse transform function.

This transform is inherently "unsafe", meaning that the input array will be overwritten during the DFT. Accordingly, the input array kField is not const like it is in all the other transform methods.

Parameters

kFields	complex values on k-grid (input, gpu mem)
rFields	real values on r-grid (output, gpu mem)

Definition at line 225 of file FFTBatched.tpp.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), UTIL_CHECK, and UTIL_THROW.

meshDimensions()

template<int D>

const IntVec< D > & Pscf::Prdc::Cuda::FFTBatched< D >::meshDimensions ( ) const

inline

Return the dimensions of the grid for which this was allocated.

Definition at line 145 of file FFTBatched.h.

resetBatchSize()

template<int D>

void Pscf::Prdc::Cuda::FFTBatched< D >::resetBatchSize

(

int

batchSize

)

Set the batch size to a new value.

isSetup() must already be true.

Parameters

batchSize

The new batch size.

isSetup() must already be true.

Definition at line 124 of file FFTBatched.tpp.

References UTIL_CHECK.

isSetup()

template<int D>

bool Pscf::Prdc::Cuda::FFTBatched< D >::isSetup ( ) const

inline

Has the setup method been called?

Definition at line 150 of file FFTBatched.h.

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

• FFTBatched.h
• FFTBatched.tpp