helib::Cmodulus Class Reference

Provides FFT and iFFT routines modulo a single-precision prime. More...

#include <CModulus.h>

Public Member Functions
	Cmodulus ()
	Default constructor. More...
	Cmodulus (const Cmodulus &other)
	Cmodulus (const PAlgebra &zms, long qq, long rt)
	Constructor. More...
Cmodulus &	operator= (const Cmodulus &other)
	Copy assignment operator. More...
const PAlgebra &	getZMStar () const
unsigned long	getM () const
unsigned long	getPhiM () const
long	getQ () const
NTL::mulmod_t	getQInv () const
long	getRoot () const
const zz_pXModulus1 &	getPhimX () const
void	restoreModulus () const
	Restore NTL's current modulus. More...
void	FFT (NTL::vec_long &y, const NTL::ZZX &x) const
void	FFT (NTL::vec_long &y, const zzX &x) const
void	FFT_aux (NTL::vec_long &y, NTL::zz_pX &tmp) const
void	iFFT (NTL::zz_pX &x, const NTL::vec_long &y) const

Static Public Member Functions
static NTL::zz_pX &	getScratch_zz_pX ()
static NTL::Vec< long > &	getScratch_vec_long ()
static NTL::fftRep &	getScratch_fftRep (long k)

Detailed Description

Provides FFT and iFFT routines modulo a single-precision prime.

On initialization, it initializes NTL's zz_pContext for this q and computes a 2m-th root of unity r mod q and also r^{-1} mod q. Thereafter this class provides FFT and iFFT routines that converts between time & frequency domains. Some tables are computed the first time that each directions is called, which are then used in subsequent computations.

The "time domain" polynomials are represented as ZZX, which are reduced modulo Phi_m(X). The "frequency domain" are just vectors of integers (vec_long), that store only the evaluation in primitive m-th roots of unity.

Constructor & Destructor Documentation

Cmodulus() [1/3]

helib::Cmodulus::Cmodulus ( )

inline

Default constructor.

Cmodulus() [2/3]

helib::Cmodulus::Cmodulus ( const Cmodulus &  other )

inline

Cmodulus() [3/3]

helib::Cmodulus::Cmodulus	(	const PAlgebra &	zms,
		long	qq,
		long	rt
	)

Constructor.

Note

Specify m and q, and optionally also the root if q == 0, then the current context is used

Member Function Documentation

FFT() [1/2]

void helib::Cmodulus::FFT	(	NTL::vec_long &	y,
		const NTL::ZZX &	x
	)		const

FFT() [2/2]

void helib::Cmodulus::FFT	(	NTL::vec_long &	y,
		const zzX &	x
	)		const

FFT_aux()

void helib::Cmodulus::FFT_aux	(	NTL::vec_long &	y,
		NTL::zz_pX &	tmp
	)		const

getM()

unsigned long helib::Cmodulus::getM ( ) const

inline

getPhiM()

unsigned long helib::Cmodulus::getPhiM ( ) const

inline

getPhimX()

const zz_pXModulus1& helib::Cmodulus::getPhimX ( ) const

inline

getQ()

long helib::Cmodulus::getQ ( ) const

inline

getQInv()

NTL::mulmod_t helib::Cmodulus::getQInv ( ) const

inline

getRoot()

long helib::Cmodulus::getRoot ( ) const

inline

getScratch_fftRep()

NTL::fftRep & helib::Cmodulus::getScratch_fftRep ( long  k )

static

getScratch_vec_long()

NTL::Vec< long > & helib::Cmodulus::getScratch_vec_long ( )

static

getScratch_zz_pX()

NTL::zz_pX & helib::Cmodulus::getScratch_zz_pX ( )

static

getZMStar()

const PAlgebra& helib::Cmodulus::getZMStar ( ) const

inline

iFFT()

void helib::Cmodulus::iFFT	(	NTL::zz_pX &	x,
		const NTL::vec_long &	y
	)		const

operator=()

Cmodulus & helib::Cmodulus::operator=

(

const Cmodulus &

other

)

Copy assignment operator.

restoreModulus()

void helib::Cmodulus::restoreModulus ( ) const

inline

Restore NTL's current modulus.