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TRandom1 Class Reference

The Ranlux Random number generator class.

The algorithm for this random engine has been taken from the original implementation in FORTRAN by Fred James as part of CLHEP.

The initialisation is carried out using a Multiplicative Congruential generator using formula constants of L'Ecuyer as described in "F.James, Comp. Phys. Comm. 60 (1990) 329-344".

Definition at line 27 of file TRandom1.h.

## Public Member Functions

TRandom1 ()
default constructor

TRandom1 (Int_t rowIndex, Int_t colIndex, Int_t lux)
constructor

TRandom1 (UInt_t seed, Int_t lux=3)
Luxury level is set in the same way as the original FORTRAN routine.

virtual ~TRandom1 ()
destructor

virtual Int_t GetLuxury () const

virtual UInt_t GetSeed () const
Get the random generator seed.

const UInt_tGetTheSeeds () const

virtual Double_t Rndm ()
Machine independent random number generator.

virtual Double_t Rndm ()
return a random number in ]0,1]

virtual Double_t Rndm (Int_t)

virtual void RndmArray (Int_t size, Double_t *vect)
return an array of random numbers in ]0,1[

virtual void RndmArray (Int_t size, Float_t *vect)
return an array of random numbers in ]0,1]

virtual void SetSeed (ULong_t seed)
Set the state of the generator providing a single seed value and using the luxury level defined when constructing the class The initialisation of the other state values is carried out using a Multiplicative Congruential generator.

virtual void SetSeed2 (UInt_t seed, Int_t lux=3)
Set the state of the generator providing a single seed value and a luxury level.

virtual void SetSeeds (const UInt_t *seeds, Int_t lux=3)
Set the state of the generator providing an array of seeds The array of seeds can be of size 24 or less.

Public Member Functions inherited from TRandom
TRandom (UInt_t seed=65539)
Default constructor. For seed see SetSeed().

virtual ~TRandom ()
Default destructor.

virtual Int_t Binomial (Int_t ntot, Double_t prob)
Generates a random integer N according to the binomial law.

virtual Double_t BreitWigner (Double_t mean=0, Double_t gamma=1)
Return a number distributed following a BreitWigner function with mean and gamma.

virtual void Circle (Double_t &x, Double_t &y, Double_t r)
Generates random vectors, uniformly distributed over a circle of given radius.

virtual Double_t Exp (Double_t tau)
Returns an exponential deviate.

virtual Double_t Gaus (Double_t mean=0, Double_t sigma=1)
Samples a random number from the standard Normal (Gaussian) Distribution with the given mean and sigma.

virtual UInt_t Integer (UInt_t imax)
Returns a random integer uniformly distributed on the interval [ 0, imax-1 ].

virtual Double_t Landau (Double_t mean=0, Double_t sigma=1)
Generate a random number following a Landau distribution with location parameter mu and scale parameter sigma: Landau( (x-mu)/sigma ) Note that mu is not the mpv(most probable value) of the Landa distribution and sigma is not the standard deviation of the distribution which is not defined.

virtual Int_t Poisson (Double_t mean)
Generates a random integer N according to a Poisson law.

virtual Double_t PoissonD (Double_t mean)
Generates a random number according to a Poisson law.

virtual void Rannor (Double_t &a, Double_t &b)
Return 2 numbers distributed following a gaussian with mean=0 and sigma=1.

virtual void Rannor (Float_t &a, Float_t &b)
Return 2 numbers distributed following a gaussian with mean=0 and sigma=1.

virtual void ReadRandom (const char *filename)
Reads saved random generator status from filename.

virtual void Sphere (Double_t &x, Double_t &y, Double_t &z, Double_t r)
Generates random vectors, uniformly distributed over the surface of a sphere of given radius.

virtual Double_t Uniform (Double_t x1, Double_t x2)
Returns a uniform deviate on the interval (x1, x2).

virtual Double_t Uniform (Double_t x1=1)
Returns a uniform deviate on the interval (0, x1).

virtual void WriteRandom (const char *filename) const
Writes random generator status to filename.

Public Member Functions inherited from TNamed
TNamed ()

TNamed (const char *name, const char *title)

TNamed (const TNamed &named)
TNamed copy ctor.

TNamed (const TString &name, const TString &title)

virtual ~TNamed ()
TNamed destructor.

virtual void Clear (Option_t *option="")
Set name and title to empty strings ("").

virtual TObjectClone (const char *newname="") const
Make a clone of an object using the Streamer facility.

virtual Int_t Compare (const TObject *obj) const
Compare two TNamed objects.

virtual void Copy (TObject &named) const
Copy this to obj.

virtual void FillBuffer (char *&buffer)
Encode TNamed into output buffer.

virtual const char * GetName () const
Returns name of object.

virtual const char * GetTitle () const
Returns title of object.

virtual ULong_t Hash () const
Return hash value for this object.

virtual Bool_t IsSortable () const

virtual void ls (Option_t *option="") const
List TNamed name and title.

TNamedoperator= (const TNamed &rhs)
TNamed assignment operator.

virtual void Print (Option_t *option="") const
Print TNamed name and title.

virtual void SetName (const char *name)
Set the name of the TNamed.

virtual void SetNameTitle (const char *name, const char *title)
Set all the TNamed parameters (name and title).

virtual void SetTitle (const char *title="")
Set the title of the TNamed.

virtual Int_t Sizeof () const
Return size of the TNamed part of the TObject.

Public Member Functions inherited from TObject
TObject ()
TObject constructor.

TObject (const TObject &object)
TObject copy ctor.

virtual ~TObject ()
TObject destructor.

void AbstractMethod (const char *method) const
Use this method to implement an "abstract" method that you don't want to leave purely abstract.

Append graphics object to current pad.

virtual void Browse (TBrowser *b)
Browse object. May be overridden for another default action.

ULong_t CheckedHash ()
Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object.

virtual const char * ClassName () const
Returns name of class to which the object belongs.

virtual void Delete (Option_t *option="")
Delete this object.

virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
Computes distance from point (px,py) to the object.

virtual void Draw (Option_t *option="")
Default Draw method for all objects.

virtual void DrawClass () const
Draw class inheritance tree of the class to which this object belongs.

virtual TObjectDrawClone (Option_t *option="") const
Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad).

virtual void Dump () const
Dump contents of object on stdout.

virtual void Error (const char *method, const char *msgfmt,...) const
Issue error message.

virtual void Execute (const char *method, const char *params, Int_t *error=0)
Execute method on this object with the given parameter string, e.g.

virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
Execute method on this object with parameters stored in the TObjArray.

virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
Execute action corresponding to an event at (px,py).

virtual void Fatal (const char *method, const char *msgfmt,...) const
Issue fatal error message.

virtual TObjectFindObject (const char *name) const
Must be redefined in derived classes.

virtual TObjectFindObject (const TObject *obj) const
Must be redefined in derived classes.

virtual Option_tGetDrawOption () const
Get option used by the graphics system to draw this object.

virtual const char * GetIconName () const
Returns mime type name of object.

virtual char * GetObjectInfo (Int_t px, Int_t py) const
Returns string containing info about the object at position (px,py).

virtual Option_tGetOption () const

virtual UInt_t GetUniqueID () const
Return the unique object id.

virtual Bool_t HandleTimer (TTimer *timer)
Execute action in response of a timer timing out.

Bool_t HasInconsistentHash () const
Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e.

virtual void Info (const char *method, const char *msgfmt,...) const
Issue info message.

virtual Bool_t InheritsFrom (const char *classname) const
Returns kTRUE if object inherits from class "classname".

virtual Bool_t InheritsFrom (const TClass *cl) const
Returns kTRUE if object inherits from TClass cl.

virtual void Inspect () const
Dump contents of this object in a graphics canvas.

void InvertBit (UInt_t f)

virtual Bool_t IsEqual (const TObject *obj) const
Default equal comparison (objects are equal if they have the same address in memory).

virtual Bool_t IsFolder () const
Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).

R__ALWAYS_INLINE Bool_t IsOnHeap () const

R__ALWAYS_INLINE Bool_t IsZombie () const

void MayNotUse (const char *method) const
Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary).

virtual Bool_t Notify ()
This method must be overridden to handle object notification.

void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
Use this method to declare a method obsolete.

void operator delete (void *ptr)
Operator delete.

void operator delete[] (void *ptr)
Operator delete [].

voidoperator new (size_t sz)

voidoperator new (size_t sz, void *vp)

voidoperator new[] (size_t sz)

voidoperator new[] (size_t sz, void *vp)

TObjectoperator= (const TObject &rhs)
TObject assignment operator.

virtual void Paint (Option_t *option="")
This method must be overridden if a class wants to paint itself.

virtual void Pop ()
Pop on object drawn in a pad to the top of the display list.

virtual Int_t Read (const char *name)
Read contents of object with specified name from the current directory.

virtual void RecursiveRemove (TObject *obj)
Recursively remove this object from a list.

void ResetBit (UInt_t f)

virtual void SaveAs (const char *filename="", Option_t *option="") const
Save this object in the file specified by filename.

virtual void SavePrimitive (std::ostream &out, Option_t *option="")
Save a primitive as a C++ statement(s) on output stream "out".

void SetBit (UInt_t f)

void SetBit (UInt_t f, Bool_t set)
Set or unset the user status bits as specified in f.

virtual void SetDrawOption (Option_t *option="")
Set drawing option for object.

virtual void SetUniqueID (UInt_t uid)
Set the unique object id.

virtual void SysError (const char *method, const char *msgfmt,...) const
Issue system error message.

R__ALWAYS_INLINE Bool_t TestBit (UInt_t f) const

Int_t TestBits (UInt_t f) const

virtual void UseCurrentStyle ()
Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked.

virtual void Warning (const char *method, const char *msgfmt,...) const
Issue warning message.

virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
Write this object to the current directory.

virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
Write this object to the current directory.

Public Member Functions inherited from ROOT::Math::TRandomEngine
virtual ~TRandomEngine ()

## Static Public Member Functions

static void GetTableSeeds (UInt_t *seeds, Int_t index)
static function returning the table of seeds

Static Public Member Functions inherited from TObject
static Long_t GetDtorOnly ()
Return destructor only flag.

static Bool_t GetObjectStat ()
Get status of object stat flag.

static void SetDtorOnly (void *obj)
Set destructor only flag.

static void SetObjectStat (Bool_t stat)
Turn on/off tracking of objects in the TObjectTable.

## Protected Attributes

Float_t fCarry

Int_t fCount24

Float_t fFloatSeedTable [24]

Int_t fIlag

const Int_t fIntModulus

Int_t fJlag

Int_t fLuxury

const Double_t fMantissaBit12

const Double_t fMantissaBit24

Int_t fNskip

const UInt_tfTheSeeds

Protected Attributes inherited from TRandom
UInt_t fSeed

Protected Attributes inherited from TNamed
TString fName

TString fTitle

## Static Protected Attributes

static Int_t fgMaxIndex = 215

static Int_t fgNumEngines = 0

Public Types inherited from TObject
enum  {
kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 ,
}

enum  { kSingleKey = BIT(0) , kOverwrite = BIT(1) , kWriteDelete = BIT(2) }

enum  EDeprecatedStatusBits { kObjInCanvas = BIT(3) }

enum  EStatusBits {
kCanDelete = BIT(0) , kMustCleanup = BIT(3) , kIsReferenced = BIT(4) , kHasUUID = BIT(5) ,
kCannotPick = BIT(6) , kNoContextMenu = BIT(8) , kInvalidObject = BIT(13)
}

Protected Types inherited from TObject
enum  { kOnlyPrepStep = BIT(3) }

Protected Member Functions inherited from TObject
virtual void DoError (int level, const char *location, const char *fmt, va_list va) const
Interface to ErrorHandler (protected).

void MakeZombie ()

#include <TRandom1.h>

Inheritance diagram for TRandom1:
[legend]

## ◆ TRandom1() [1/3]

 TRandom1::TRandom1 ( )

default constructor

Definition at line 287 of file TRandom1.cxx.

## ◆ TRandom1() [2/3]

 TRandom1::TRandom1 ( UInt_t seed, Int_t lux = 3 )

Luxury level is set in the same way as the original FORTRAN routine.

level 0 (p=24): equivalent to the original RCARRY of Marsaglia and Zaman, very long period, but fails many tests. level 1 (p=48): considerable improvement in quality over level 0, now passes the gap test, but still fails spectral test. level 2 (p=97): passes all known tests, but theoretically still defective. level 3 (p=223): DEFAULT VALUE. Any theoretically possible correlations have very small chance of being observed. level 4 (p=389): highest possible luxury, all 24 bits chaotic.

Definition at line 265 of file TRandom1.cxx.

## ◆ TRandom1() [3/3]

 TRandom1::TRandom1 ( Int_t rowIndex, Int_t colIndex, Int_t lux )

constructor

Definition at line 314 of file TRandom1.cxx.

## ◆ ~TRandom1()

 TRandom1::~TRandom1 ( )
virtual

destructor

Definition at line 341 of file TRandom1.cxx.

## ◆ GetLuxury()

 virtual Int_t TRandom1::GetLuxury ( ) const
inlinevirtual

Definition at line 49 of file TRandom1.h.

## ◆ GetSeed()

 virtual UInt_t TRandom1::GetSeed ( ) const
inlinevirtual

Get the random generator seed.

Note that this function returns the given seed only when using as random generator engine TRandom itself, which is an LCG generator and it has as seed (state) only one 32 bit word. In case of the other generators GetSeed will return one of the state elements and not the given seed. See the documentation of the corresponding generator used (for example TRandom3::GetSeed() when using TRandom3 or gRandom. If one needs to save the generator seed in order to be used later for obtaining reproducible numbers, one should store the full generator, either in a file or in memory in a separate TRandom object. Here is an example on how to store reproducible states:

// set a unique seed
// save generator state in a different TRandom instance
TRandom* rngSaved = static_cast<TRandom*>(gRandom->Clone());
// now both rngSaved and gRandom will produce the same sequence of numbers
for (int i = 0; i < 10; ++i )
std::cout << "genrated number from gRandom : " << gRandom->Rndm() << " from saved generator " <<
rngSaved->Rndm() << std::endl;
R__EXTERN TRandom * gRandom
Definition TRandom1.h:71
virtual TObject * Clone(const char *newname="") const
Make a clone of an object using the Streamer facility.
Definition TNamed.cxx:74
This is the base class for the ROOT Random number generators.
Definition TRandom.h:27
virtual void SetSeed(ULong_t seed=0)
Set the random generator seed.
Definition TRandom.cxx:608
virtual Double_t Rndm()
Machine independent random number generator.
Definition TRandom.cxx:552

Reimplemented from TRandom.

Definition at line 51 of file TRandom1.h.

## ◆ GetTableSeeds()

 void TRandom1::GetTableSeeds ( UInt_t * seeds, Int_t index )
static

static function returning the table of seeds

Definition at line 348 of file TRandom1.cxx.

## ◆ GetTheSeeds()

 const UInt_t * TRandom1::GetTheSeeds ( ) const
inline

Definition at line 53 of file TRandom1.h.

## ◆ Rndm() [1/3]

 Double_t TRandom::Rndm ( )
virtual

Machine independent random number generator.

Based on the BSD Unix (Rand) Linear congrential generator. Produces uniformly-distributed floating points between 0 and 1. Identical sequence on all machines of >= 32 bits. Periodicity = 2**31, generates a number in (0,1). Note that this is a generator which is known to have defects (the lower random bits are correlated) and therefore should NOT be used in any statistical study).

Reimplemented from TRandom.

Definition at line 49 of file TRandom.cxx.

## ◆ Rndm() [2/3]

 Double_t TRandom1::Rndm ( )
virtual

return a random number in ]0,1]

Reimplemented from TRandom.

Definition at line 360 of file TRandom1.cxx.

## ◆ Rndm() [3/3]

 virtual Double_t TRandom::Rndm ( Int_t )
inlinevirtual

Reimplemented from TRandom.

Definition at line 51 of file TRandom.h.

## ◆ RndmArray() [1/2]

 void TRandom1::RndmArray ( Int_t size, Double_t * vect )
virtual

return an array of random numbers in ]0,1[

Reimplemented from TRandom.

Definition at line 421 of file TRandom1.cxx.

## ◆ RndmArray() [2/2]

 void TRandom1::RndmArray ( Int_t size, Float_t * vect )
virtual

return an array of random numbers in ]0,1]

Reimplemented from TRandom.

Definition at line 413 of file TRandom1.cxx.

## ◆ SetSeed()

 void TRandom1::SetSeed ( ULong_t seed )
virtual

Set the state of the generator providing a single seed value and using the luxury level defined when constructing the class The initialisation of the other state values is carried out using a Multiplicative Congruential generator.

Note: When seed = 0, a random and unique seed is generated

Parameters
 [in] seed seed value (note special case if seed=0)

Reimplemented from TRandom.

Definition at line 598 of file TRandom1.cxx.

## ◆ SetSeed2()

 void TRandom1::SetSeed2 ( UInt_t seed, Int_t lux = 3 )
virtual

Set the state of the generator providing a single seed value and a luxury level.

The initialisation of the other state values is carried out using a Multiplicative Congruential generator using formula constants of L'Ecuyer as described in "A review of pseudorandom number generators" (Fred James) published in Computer Physics Communications 60 (1990) pages 329-344

Note: When the provided seed = 0, a random and unique seed is generated

Parameters
 [in] seed seed value (note special case if seed=0) [in] lux Luxury level

Definition at line 568 of file TRandom1.cxx.

## ◆ SetSeeds()

 void TRandom1::SetSeeds ( const UInt_t * seeds, Int_t lux = 3 )
virtual

Set the state of the generator providing an array of seeds The array of seeds can be of size 24 or less.

In case of an array of n seeds with n < 24 the n+1 element must be equal to zero. The other elements are the initialized using a Multiplicative Congruential generator using formula constants of L'Ecuyer as described in "A review of pseudorandom number generators" (Fred James) published in Computer Physics Communications 60 (1990) pages 329-344

Parameters
 [in] seeds array of seeds (size from 1 to 24) [in] lux Luxury level

Definition at line 487 of file TRandom1.cxx.

## ◆ fCarry

 Float_t TRandom1::fCarry
protected

Definition at line 36 of file TRandom1.h.

## ◆ fCount24

 Int_t TRandom1::fCount24
protected

Definition at line 34 of file TRandom1.h.

## ◆ fFloatSeedTable

 Float_t TRandom1::fFloatSeedTable[24]
protected

Definition at line 35 of file TRandom1.h.

## ◆ fgMaxIndex

 int TRandom1::fgMaxIndex = 215
staticprotected

Definition at line 39 of file TRandom1.h.

## ◆ fgNumEngines

 int TRandom1::fgNumEngines = 0
staticprotected

Definition at line 38 of file TRandom1.h.

## ◆ fIlag

 Int_t TRandom1::fIlag
protected

Definition at line 32 of file TRandom1.h.

## ◆ fIntModulus

 const Int_t TRandom1::fIntModulus
protected

Definition at line 37 of file TRandom1.h.

## ◆ fJlag

 Int_t TRandom1::fJlag
protected

Definition at line 33 of file TRandom1.h.

## ◆ fLuxury

 Int_t TRandom1::fLuxury
protected

Definition at line 31 of file TRandom1.h.

## ◆ fMantissaBit12

 const Double_t TRandom1::fMantissaBit12
protected

Definition at line 42 of file TRandom1.h.

## ◆ fMantissaBit24

 const Double_t TRandom1::fMantissaBit24
protected

Definition at line 41 of file TRandom1.h.

## ◆ fNskip

 Int_t TRandom1::fNskip
protected

Definition at line 30 of file TRandom1.h.

## ◆ fTheSeeds

 const UInt_t* TRandom1::fTheSeeds
protected

Definition at line 40 of file TRandom1.h.

Libraries for TRandom1:

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