Random Number Generation

Collaboration diagram for Random Number Generation:

Classes
class	CRandom
	CRandom:: More...
class	CRandomException
	Exceptions generated by CRandom class. More...

Typedefs
typedef Uint4	CRandom::TValue
	Type of the generated integer value and/or the seed value. More...

Enumerations
enum	CRandom::EGetRandMethod { CRandom::eGetRand_LFG , CRandom::eGetRand_Sys }
	Random generator to use in the GetRand() functions. More...
enum	{ CRandom::kStateSize = 33 }
enum	CRandomException::EErrCode { CRandomException::eUnavailable , CRandomException::eUnexpectedRandMethod , CRandomException::eSysGeneratorError }

Functions
	CRandom::CRandom (EGetRandMethod method=eGetRand_LFG)
	If "method" is: More...
	CRandom::CRandom (TValue seed)
	Use LFG random generator seeded with "seed". More...
TValue	CRandom::GetRand (void)
	Get the next random number in the interval [0..GetMax()] (inclusive) More...
TValue	CRandom::GetRand (TValue min_value, TValue max_value)
	Get random number in the interval [min_value..max_value] (inclusive) More...
Uint8	CRandom::GetRandUint8 (void)
	Get random Uint8 number. More...
Uint8	CRandom::GetRandUint8 (Uint8 min_value, Uint8 max_value)
	Get random number in the interval [min_value..max_value] (inclusive) More...
size_t	CRandom::GetRandSize_t (size_t min_value, size_t max_value)
	Get random number in the interval [min_value..max_value] (inclusive) More...
TValue	CRandom::GetRandIndex (TValue size)
	Get random number in the interval [0..size-1] (e.g. More...
Uint8	CRandom::GetRandIndexUint8 (Uint8 size)
	Get random number in the interval [0..size-1] (e.g. More...
size_t	CRandom::GetRandIndexSize_t (size_t size)
	Get random number in the interval [0..size-1] (e.g. More...
static TValue	CRandom::GetMax (void)
	The max. value GetRand() returns. More...
EGetRandMethod	CRandom::GetRandMethod (void) const
	Get the random generator type. More...
void	CRandom::Randomize (void)
	Re-initialize (re-seed) the generator using platform-specific randomization. More...
void	CRandom::SetSeed (TValue seed)
	Seed the random number generator with "seed". More...
TValue	CRandom::GetSeed (void) const
	Get the last set seed (LFG only) More...
void	CRandom::Reset (void)
	Reset random number generator to initial startup condition (LFG only) More...
TValue	CRandom::x_GetRand32Bits (void)
Uint8	CRandom::x_GetRand64Bits (void)
TValue	CRandom::x_GetSysRand32Bits (void) const
	CRandom::CRandom (const CRandom &)
CRandom &	CRandom::operator= (const CRandom &)
virtual const char *	CRandomException::GetErrCodeString (void) const override
	Get error code interpreted as text. More...
	CRandomException::NCBI_EXCEPTION_DEFAULT (CRandomException, CException)

Variables
EGetRandMethod	CRandom::m_RandMethod
TValue	CRandom::m_State [kStateSize]
int	CRandom::m_RJ
int	CRandom::m_RK
TValue	CRandom::m_Seed

Detailed Description

Typedef Documentation

TValue

typedef Uint4 CRandom::TValue

Type of the generated integer value and/or the seed value.

Definition at line 69 of file random_gen.hpp.

Enumeration Type Documentation

anonymous enum

anonymous enum

private

Enumerator
kStateSize

Definition at line 159 of file random_gen.hpp.

EErrCode

enum CRandomException::EErrCode

Enumerator
eUnavailable	System-dependent generator is not available.
eUnexpectedRandMethod	The user called method which is not allowed for the used generator.
eSysGeneratorError	Error getting a random value from the system-dependent generator.

Definition at line 182 of file random_gen.hpp.

EGetRandMethod

enum CRandom::EGetRandMethod

Random generator to use in the GetRand() functions.

Enumerator
eGetRand_LFG	Use lagged Fibonacci (LFG) random number generator.
eGetRand_Sys	Use system-dependent random generator.

Definition at line 72 of file random_gen.hpp.

Function Documentation

CRandom() [1/3]

CRandom::CRandom ( const CRandom &  )

private

CRandom() [2/3]

CRandom::CRandom

(

EGetRandMethod

method = eGetRand_LFG

)

If "method" is:

• eGetRand_LFG – use LFG generator seeded with a hard-coded seed
• eGetRand_Sys – use system-dependent generator

Definition at line 215 of file random_gen.cpp.

References CRandom::eGetRand_Sys, NCBI_THROW, CRandom::Reset(), and s_RandomSupplier.

CRandom() [3/3]

CRandom::CRandom

(

TValue

seed

)

Use LFG random generator seeded with "seed".

Definition at line 227 of file random_gen.cpp.

References seed, and CRandom::SetSeed().

GetErrCodeString()

virtual const char* CRandomException::GetErrCodeString ( void  ) const

inlineoverridevirtual

Get error code interpreted as text.

Reimplemented from CException.

Definition at line 190 of file random_gen.hpp.

References CRandomException::eSysGeneratorError, CRandomException::eUnavailable, CRandomException::eUnexpectedRandMethod, CException::GetErrCode(), and CException::GetErrCodeString().

GetMax()

CRandom::TValue CRandom::GetMax ( void  )

inlinestatic

The max. value GetRand() returns.

Definition at line 295 of file random_gen.hpp.

Referenced by CNCDistributionConf::GenerateBlobKey(), and alp_data::ran2().

GetRand() [1/2]

CRandom::TValue CRandom::GetRand ( TValue  min_value, TValue  max_value  )

inline

Get random number in the interval [min_value..max_value] (inclusive)

See also

EGetRandMethod

Note

eGetRand_LFG generator could be 100 times faster than eGetRand_Sys one

Definition at line 277 of file random_gen.hpp.

References CRandom::GetRandIndex(), and min_value.

GetRand() [2/2]

CRandom::TValue CRandom::GetRand ( void  )

inline

Get the next random number in the interval [0..GetMax()] (inclusive)

See also

EGetRandMethod

Note

eGetRand_LFG generator could be 100 times faster than eGetRand_Sys one

Definition at line 238 of file random_gen.hpp.

References CRandom::x_GetRand32Bits().

Referenced by BOOST_AUTO_TEST_CASE(), CNCDistributionConf::GenerateBlobKey(), CNcbiEncryptApp::GenerateKey(), TestUtil::GenerateRandomSeqid_Gi(), GetKValues(), CDiscreteDistributionImpl::GetNextValue(), SCompoundIDPoolImpl::GetRand(), CMTTestThread::GetRandomId(), GetRandomNumbers(), CMTTestThread::Main(), CSeqportUtil_implementation::MapIupacnaToNcbi2na(), CSeqportUtil_implementation::MapNcbi4naToNcbi2na(), SNetServiceIterator_RandomPivot::Next(), CSymDustMasker::CIupac2Ncbi2na_converter::operator()(), alp_data::ran2(), CDbapiSampleApp::Run(), s_GetRand(), s_GetRandomNumbers(), s_Ncbi4naToNcbi2na(), s_SetNextTime(), CRandom::SetSeed(), CNCActiveSyncControl::x_FinishScanSlots(), CElementaryMatching::x_InitBasic(), and CAmbigDataBuilder::x_Random().

GetRandIndex()

CRandom::TValue CRandom::GetRandIndex ( TValue  size )

inline

Get random number in the interval [0..size-1] (e.g.

index in array)

See also

EGetRandMethod

Note

eGetRand_LFG generator could be 100 times faster than eGetRand_Sys one

Definition at line 251 of file random_gen.hpp.

References r(), ncbi::grid::netcache::search::fields::size, and CRandom::x_GetRand32Bits().

Referenced by CRandom::GetRand(), CRandom::GetRandIndexSize_t(), and CRandom::GetRandIndexUint8().

GetRandIndexSize_t()

size_t CRandom::GetRandIndexSize_t ( size_t  size )

inline

Get random number in the interval [0..size-1] (e.g.

index in array)

See also

EGetRandMethod

Note

eGetRand_LFG generator could be 100 times faster than eGetRand_Sys one

Definition at line 267 of file random_gen.hpp.

References CRandom::GetRandIndex(), CRandom::GetRandIndexUint8(), and ncbi::grid::netcache::search::fields::size.

Referenced by CRandom::GetRandSize_t().

GetRandIndexUint8()

Uint8 CRandom::GetRandIndexUint8

(

Uint8

size

)

Get random number in the interval [0..size-1] (e.g.

index in array)

See also

EGetRandMethod

Note

eGetRand_LFG generator could be 100 times faster than eGetRand_Sys one

Definition at line 331 of file random_gen.cpp.

References CRandom::GetRandIndex(), CRandom::GetRandUint8(), kMax_UI4, r(), and ncbi::grid::netcache::search::fields::size.

Referenced by CRandom::GetRandIndexSize_t(), and CRandom::GetRandUint8().

GetRandMethod()

CRandom::EGetRandMethod CRandom::GetRandMethod ( void  ) const

inline

Get the random generator type.

Definition at line 301 of file random_gen.hpp.

References CRandom::m_RandMethod.

GetRandSize_t()

size_t CRandom::GetRandSize_t ( size_t  min_value, size_t  max_value  )

inline

Get random number in the interval [min_value..max_value] (inclusive)

See also

EGetRandMethod

Note

eGetRand_LFG generator could be 100 times faster than eGetRand_Sys one

Definition at line 289 of file random_gen.hpp.

References CRandom::GetRandIndexSize_t(), and min_value.

GetRandUint8() [1/2]

Uint8 CRandom::GetRandUint8 ( Uint8  min_value, Uint8  max_value  )

inline

Get random number in the interval [min_value..max_value] (inclusive)

See also

EGetRandMethod

Note

eGetRand_LFG generator could be 100 times faster than eGetRand_Sys one

Definition at line 283 of file random_gen.hpp.

References CRandom::GetRandIndexUint8(), and min_value.

GetRandUint8() [2/2]

Uint8 CRandom::GetRandUint8 ( void  )

inline

Get random Uint8 number.

See also

EGetRandMethod

Note

eGetRand_LFG generator could be 100 times faster than eGetRand_Sys one

Definition at line 244 of file random_gen.hpp.

References CRandom::x_GetRand32Bits().

Referenced by NDirectNetStorageImpl::SContext::Create(), CRandom::GetRandIndexUint8(), and CPubseqGatewayApp::Run().

GetSeed()

CRandom::TValue CRandom::GetSeed

(

void

)

const

Get the last set seed (LFG only)

Attention

Throw exception if non-LFG (i.e. system) generator is used.

Definition at line 312 of file random_gen.cpp.

References CRandom::eGetRand_Sys, CRandom::m_RandMethod, CRandom::m_Seed, and NCBI_THROW.

NCBI_EXCEPTION_DEFAULT()

CRandomException::NCBI_EXCEPTION_DEFAULT	(	CRandomException	,
		CException
	)

operator=()

CRandom& CRandom::operator= ( const CRandom &  )

private

Randomize()

void CRandom::Randomize

(

void

)

Re-initialize (re-seed) the generator using platform-specific randomization.

Note

Does nothing if system generator is used.

Definition at line 267 of file random_gen.cpp.

References CTime::eCurrent, CRandom::eGetRand_Sys, CCurrentProcess::GetPid(), CThread::GetSelf(), CRandom::m_RandMethod, CTime::NanoSecond(), s_RandomSupplier, CTime::Second(), seed, and CRandom::SetSeed().

Referenced by CNcbiEncryptApp::GenerateKey(), and NDirectNetStorageImpl::SContext::Init().

Reset()

void CRandom::Reset

(

void

)

Reset random number generator to initial startup condition (LFG only)

Attention

Throw exception if non-LFG (i.e. system) generator is used.

Definition at line 234 of file random_gen.cpp.

References _ASSERT, CRandom::eGetRand_Sys, i, kStateOffset, CRandom::kStateSize, CRandom::m_RandMethod, CRandom::m_RJ, CRandom::m_RK, CRandom::m_State, and NCBI_THROW.

Referenced by CSubjectRangesSet::AddRange(), CRandom::CRandom(), and CSeqDBVol::SetOffsetRanges().

SetSeed()

void CRandom::SetSeed

(

TValue

seed

)

Seed the random number generator with "seed".

Attention

Throw exception if non-LFG (i.e. system) generator is used.

Definition at line 287 of file random_gen.cpp.

References _ASSERT, CRandom::eGetRand_Sys, CRandom::GetRand(), i, kStateOffset, CRandom::kStateSize, CRandom::m_RandMethod, CRandom::m_RJ, CRandom::m_RK, CRandom::m_Seed, CRandom::m_State, NCBI_THROW, and seed.

Referenced by alp_data::alp_data(), CRandom::CRandom(), CSeqportUtil_implementation::MapIupacnaToNcbi2na(), CSeqportUtil_implementation::MapNcbi4naToNcbi2na(), and CRandom::Randomize().

x_GetRand32Bits()

CRandom::TValue CRandom::x_GetRand32Bits ( void  )

inlineprivate

Definition at line 217 of file random_gen.hpp.

References CRandom::eGetRand_Sys, CRandom::kStateSize, CRandom::m_RandMethod, CRandom::m_RJ, CRandom::m_RK, CRandom::m_State, r(), and CRandom::x_GetSysRand32Bits().

Referenced by CRandom::GetRand(), CRandom::GetRandIndex(), and CRandom::GetRandUint8().

x_GetRand64Bits()

Uint8 CRandom::x_GetRand64Bits ( void  )

private

x_GetSysRand32Bits()

CRandom::TValue CRandom::x_GetSysRand32Bits ( void  ) const

private

Definition at line 323 of file random_gen.cpp.

References r(), and s_RandomSupplier.

Referenced by CRandom::x_GetRand32Bits().

Variable Documentation

m_RandMethod

EGetRandMethod CRandom::m_RandMethod

private

Definition at line 162 of file random_gen.hpp.

Referenced by CRandom::GetRandMethod(), CRandom::GetSeed(), CRandom::Randomize(), CRandom::Reset(), CRandom::SetSeed(), and CRandom::x_GetRand32Bits().

m_RJ

int CRandom::m_RJ

private

Definition at line 164 of file random_gen.hpp.

Referenced by CRandom::Reset(), CRandom::SetSeed(), and CRandom::x_GetRand32Bits().

m_RK

int CRandom::m_RK

private

Definition at line 165 of file random_gen.hpp.

Referenced by CRandom::Reset(), CRandom::SetSeed(), and CRandom::x_GetRand32Bits().

m_Seed

TValue CRandom::m_Seed

private

Definition at line 166 of file random_gen.hpp.

Referenced by CRandom::GetSeed(), and CRandom::SetSeed().

m_State

TValue CRandom::m_State[kStateSize]

private

Definition at line 163 of file random_gen.hpp.

Referenced by CRandom::Reset(), CRandom::SetSeed(), and CRandom::x_GetRand32Bits().