LatticeTester::Random Namespace Reference

This class generates random numbers (in fact pseudo-random numbers). More...

Functions
double	randU01 ()
	Returns a random number in \([0, 1)\). More...
std::int64_t	randInt (std::int64_t i, std::int64_t j)
	Return a random integer in \([i, j]\). More...
NTL::ZZ	randInt (NTL::ZZ i, NTL::ZZ j)
	This is an overload of the previous method to create an NTL::ZZ integer in the range \([i,j]\). More...
std::uint64_t	randBits (int s)
	Returns random blocks of \(s\) bits ( \(s\)-bit integers). More...
void	setSeed (std::uint64_t seed=GERME)
	Sets the seed of the generator. More...

Detailed Description

This class generates random numbers (in fact pseudo-random numbers).

The generator used is the 64-bits generator LFSR258 from L'Ecuyer [16] with period length near \(2^{258}\) for 64-bits machines, and the 32-bits generator LFSR113 from L'Ecuyer [16] with period length near \(2^{113}\) on 32-bits machines. Thus the random numbers generated will be different on 32-bits and 64-bits machines.

Function Documentation

randBits()

uint64_t LatticeTester::Random::randBits

(

int

s

)

Returns random blocks of \(s\) bits ( \(s\)-bit integers).

randInt() [1/2]

std::int64_t LatticeTester::Random::randInt	(	std::int64_t	i,
		std::int64_t	j
	)

Return a random integer in \([i, j]\).

The numbers \(i\) and \(j\) can occur. Restriction: \(i < j\). The generated number is limited to 62 bits.

randInt() [2/2]

NTL::ZZ LatticeTester::Random::randInt	(	NTL::ZZ	i,
		NTL::ZZ	j
	)

This is an overload of the previous method to create an NTL::ZZ integer in the range \([i,j]\).

NTL has a method to generate pseudo random numbers in a given range, but it is not deterministic. This method concatenates random bits until it has a big enough number and tries to assign the correct integer to it.

randU01()

double LatticeTester::Random::randU01

(

)

Returns a random number in \([0, 1)\).

The number has 53 random bits of resolution on 64-bits machines, and 32 random bits on 32-bits machines.

setSeed()

void LatticeTester::Random::setSeed

(

std::uint64_t

seed = GERME

)

Sets the seed of the generator.

If not called, a default seed is used.