#include <NekFFTW.h>

Inheritance diagram for Nektar::LibUtilities::NekFFTW:

Collaboration diagram for Nektar::LibUtilities::NekFFTW:

Public Member Functions
	NekFFTW (int N)

virtual	~NekFFTW ()

virtual void	v_FFTFwdTrans (Array< OneD, NekDouble > &inarray, Array< OneD, NekDouble > &outarray)

virtual void	v_FFTBwdTrans (Array< OneD, NekDouble > &inarray, Array< OneD, NekDouble > &outarray)

Public Member Functions inherited from Nektar::LibUtilities::NektarFFT
	NektarFFT (int N)
	Initialises NektarFFT class members. More...

	~NektarFFT ()

void	FFTFwdTrans (Array< OneD, NekDouble > &phy, Array< OneD, NekDouble > &coef)

void	FFTBwdTrans (Array< OneD, NekDouble > &coef, Array< OneD, NekDouble > &phys)

Static Public Member Functions
static NektarFFTSharedPtr	create (int N)
	Creates an instance of this class. More...

Static Public Attributes
static std::string	className
	Name of class. More...

Protected Member Functions
void	Reshuffle_FFTW2Nek (Array< OneD, NekDouble > &coef)

void	Reshuffle_Nek2FFTW (Array< OneD, NekDouble > &coef)

Protected Attributes
Array< OneD, NekDouble >	m_FFTW_w

Array< OneD, NekDouble >	m_FFTW_w_inv

Array< OneD, NekDouble >	phys

Array< OneD, NekDouble >	coef

Array< OneD, NekDouble >	m_wsp

fftw_plan	plan_backward

fftw_plan	plan_forward

Additional Inherited Members
Public Attributes inherited from Nektar::LibUtilities::NektarFFT
int	m_N

Detailed Description

Definition at line 61 of file NekFFTW.h.

Constructor & Destructor Documentation

Nektar::LibUtilities::NekFFTW::NekFFTW ( int N )

Definition at line 48 of file NekFFTW.cpp.

References coef, m_FFTW_w, m_FFTW_w_inv, Nektar::LibUtilities::NektarFFT::m_N, m_wsp, phys, plan_backward, and plan_forward.

                 : NektarFFT(N)
         {
             m_wsp = Array<OneD, NekDouble>(m_N);
             phys = Array<OneD,NekDouble>(m_N);
             coef = Array<OneD,NekDouble>(m_N);
 
             plan_forward  = fftw_plan_r2r_1d(m_N, &phys[0], &coef[0],
                                              FFTW_R2HC, FFTW_ESTIMATE);
             plan_backward = fftw_plan_r2r_1d(m_N, &coef[0], &phys[0],
                                              FFTW_HC2R, FFTW_ESTIMATE);
 
             m_FFTW_w = Array<OneD,NekDouble>(m_N);
             m_FFTW_w_inv = Array<OneD,NekDouble>(m_N);
 
             m_FFTW_w[0] = 1.0/(NekDouble)m_N;
             m_FFTW_w[1] = 0.0;
 
             m_FFTW_w_inv[0] = m_N;
             m_FFTW_w_inv[1] = 0.0;
 
             for(int i=2;i<m_N;i++)
             {
                 m_FFTW_w[i]     = m_FFTW_w[0]*2;
                 m_FFTW_w_inv[i] = m_FFTW_w_inv[0]/2;
             }
         }

Nektar::LibUtilities::NekFFTW::~NekFFTW ( )

virtual

Definition at line 77 of file NekFFTW.cpp.

         {
 
         }

Member Function Documentation

static NektarFFTSharedPtr Nektar::LibUtilities::NekFFTW::create ( int N )

inlinestatic

Creates an instance of this class.

Definition at line 66 of file NekFFTW.h.

References Nektar::MemoryManager< DataType >::AllocateSharedPtr().

             {
                 return MemoryManager<NekFFTW>::AllocateSharedPtr(N);
             }

void Nektar::LibUtilities::NekFFTW::Reshuffle_FFTW2Nek ( Array< OneD, NekDouble > & coef )

protected

Reshuffling routines to put the coefficients in Nektar++/FFTW format. The routines take as an input the number of points N, the vector of coeffcients and the vector containing the weights of the numerical integration. The routines modify directly the coef vector.

Definition at line 111 of file NekFFTW.cpp.

References m_FFTW_w, Nektar::LibUtilities::NektarFFT::m_N, m_wsp, Vmath::Vcopy(), and Vmath::Vmul().

Referenced by v_FFTFwdTrans().

         {
             int halfN = m_N/2;
 
             m_wsp[1] = coef[halfN];
 
             Vmath::Vcopy(halfN, coef, 1, m_wsp, 2);
 
             for(int i = 0; i < (halfN - 1); i++)
             {
                 m_wsp[(m_N-1)-2*i] = coef[halfN+1+i];
             }
 
             Vmath::Vmul(m_N, m_wsp, 1, m_FFTW_w, 1, coef, 1);
 
             return;
         }

void Nektar::LibUtilities::NekFFTW::Reshuffle_Nek2FFTW ( Array< OneD, NekDouble > & coef )

protected

Definition at line 130 of file NekFFTW.cpp.

References m_FFTW_w_inv, Nektar::LibUtilities::NektarFFT::m_N, m_wsp, Vmath::Smul(), Vmath::Vcopy(), and Vmath::Vmul().

Referenced by v_FFTBwdTrans().

         {
             int halfN = m_N/2;
 
             Vmath::Vmul(m_N, coef, 1, m_FFTW_w_inv, 1, coef, 1);
 
             m_wsp[halfN] = coef[1];
 
             Vmath::Vcopy(halfN, coef, 2, m_wsp, 1);
 
             for(int i = 0; i < (halfN-1); i++)
             {
                 m_wsp[halfN+1+i] = coef[(m_N-1)-2*i];
             }
 
             Vmath::Smul(m_N, 1.0/m_N, m_wsp, 1, coef, 1);
 
             return;
         }

void Nektar::LibUtilities::NekFFTW::v_FFTBwdTrans	(	Array< OneD, NekDouble > &	inarray,
		Array< OneD, NekDouble > &	outarray
	)

virtual

Reimplemented from Nektar::LibUtilities::NektarFFT.

Definition at line 97 of file NekFFTW.cpp.

References coef, Nektar::LibUtilities::NektarFFT::m_N, phys, plan_backward, Reshuffle_Nek2FFTW(), and Vmath::Vcopy().

         {
             Vmath::Vcopy(m_N, inarray, 1, coef, 1);
 
             Reshuffle_Nek2FFTW(coef);
 
             fftw_execute(plan_backward);
 
             Vmath::Vcopy(m_N, phys, 1, outarray, 1);
         }

void Nektar::LibUtilities::NekFFTW::v_FFTFwdTrans	(	Array< OneD, NekDouble > &	inarray,
		Array< OneD, NekDouble > &	outarray
	)

virtual

Reimplemented from Nektar::LibUtilities::NektarFFT.

Definition at line 83 of file NekFFTW.cpp.

References coef, Nektar::LibUtilities::NektarFFT::m_N, phys, plan_forward, Reshuffle_FFTW2Nek(), and Vmath::Vcopy().

         {
             Vmath::Vcopy(m_N, inarray, 1, phys, 1);
 
             fftw_execute(plan_forward);
 
             Reshuffle_FFTW2Nek(coef);
 
             Vmath::Vcopy(m_N, coef, 1, outarray, 1);
         }