ITK
6.0.0
Insight Toolkit
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#include <itkNormalVariateGenerator.h>
Normal random variate generator.
This generation method was initially developed and implemented by Martin Styner, University of North Carolina at Chapel Hill, and his colleagues.
You should run Initialize() function before call GetNormalVariate() function.
The following are original comments.
Revision date 31 May 1996 This is a revised version of the algorithm described in
ACM Transactions on Mathematical Software, Vol 22, No 1 March 1996, pp 119-127.
It is somewhat faster, and uses less memory as the vector of variates is updated in-situ. It has passed all the same statistical tests as described in the TOMS article, plus others. Seems OK so far.
Works well with total pool of 1024 variates, and does not need two vectors of this size, so does less damage to cache. Has been tested for frequency of tail values which should occur once in a million. OK. Other usual tests OK. About 13 % faster than TOMS version. FAST GENERATOR OF PSEUDO-RANDOM UNIT NORMAL VARIATES C.S.Wallace, Monash University, 1994
To use this code, files needing to call the generator should include:
and be linked with the math library (-lm) FastNorm.h contains declaration of the initialization routine 'initnorm()', definition of a macro 'FastGauss' used to generate variates, and three variables used in the macro. Read below for calling conventions.
THIS CODE ASSUMES TWO'S-COMPLEMENT 32-BIT INTEGER ARITHMETIC. IT ALSO ASSUMES THE 'C' COMPILER COMPILES THE LEFT-SHIFT OPERATOR "<<" AS A LOGICAL SHIFT, DISCARDING THE SIGN DIGIT AND SHIFTING IN ZEROS ON THE RIGHT, SO " X << 1" IS EQUIVALENT TO " X+X ". IT ALSO ASSUMES THE RIGHT-SHIFT OPERATOR ">>" IS SIGN-PRESERVING, SO ( -2 >> 1) = -1, ( -1>>1) = -1.
A fast generator of pseudo-random variates from the unit Normal
distribution. It keeps a pool of about 1000 variates, and generates new ones by picking 4 from the pool, rotating the 4-vector with these as its components, and replacing the old variates with the components of the rotated vector.
The program should initialize the generator by calling
initnorm(seed) with seed a int integer seed value. Different seed values will give different sequences of Normals. Then, wherever the program needs a new Normal variate, it should use the macro FastGauss, e.g. in statements like: x = FastGauss; (Sets x to a random Normal value)
Definition at line 98 of file itkNormalVariateGenerator.h.
Public Types | |
using | ConstPointer = SmartPointer< const Self > |
using | Pointer = SmartPointer< Self > |
using | Self = NormalVariateGenerator |
using | Superclass = RandomVariateGeneratorBase |
Public Types inherited from itk::Statistics::RandomVariateGeneratorBase | |
using | ConstPointer = SmartPointer< const Self > |
using | Pointer = SmartPointer< Self > |
using | Self = RandomVariateGeneratorBase |
using | Superclass = Object |
Public Types inherited from itk::Object | |
using | ConstPointer = SmartPointer< const Self > |
using | Pointer = SmartPointer< Self > |
using | Self = Object |
using | Superclass = LightObject |
Public Types inherited from itk::LightObject | |
using | ConstPointer = SmartPointer< const Self > |
using | Pointer = SmartPointer< Self > |
using | Self = LightObject |
Public Member Functions | |
const char * | GetNameOfClass () const override |
double | GetVariate () override |
void | Initialize (int randomSeed) |
const char * | GetNameOfClass () const override |
virtual double | GetVariate ()=0 |
Public Member Functions inherited from itk::Object | |
unsigned long | AddObserver (const EventObject &event, Command *cmd) const |
unsigned long | AddObserver (const EventObject &event, std::function< void(const EventObject &)> function) const |
LightObject::Pointer | CreateAnother () const override |
virtual void | DebugOff () const |
virtual void | DebugOn () const |
Command * | GetCommand (unsigned long tag) |
bool | GetDebug () const |
MetaDataDictionary & | GetMetaDataDictionary () |
const MetaDataDictionary & | GetMetaDataDictionary () const |
virtual ModifiedTimeType | GetMTime () const |
const char * | GetNameOfClass () const override |
virtual const TimeStamp & | GetTimeStamp () const |
bool | HasObserver (const EventObject &event) const |
void | InvokeEvent (const EventObject &) |
void | InvokeEvent (const EventObject &) const |
virtual void | Modified () const |
void | Register () const override |
void | RemoveAllObservers () |
void | RemoveObserver (unsigned long tag) const |
void | SetDebug (bool debugFlag) const |
void | SetReferenceCount (int) override |
void | UnRegister () const noexcept override |
void | SetMetaDataDictionary (const MetaDataDictionary &rhs) |
void | SetMetaDataDictionary (MetaDataDictionary &&rrhs) |
virtual void | SetObjectName (std::string _arg) |
virtual const std::string & | GetObjectName () const |
Public Member Functions inherited from itk::LightObject | |
Pointer | Clone () const |
virtual Pointer | CreateAnother () const |
virtual void | Delete () |
virtual const char * | GetNameOfClass () const |
virtual int | GetReferenceCount () const |
void | Print (std::ostream &os, Indent indent=0) const |
virtual void | Register () const |
virtual void | SetReferenceCount (int) |
virtual void | UnRegister () const noexcept |
Static Public Member Functions | |
static Pointer | New () |
Static Public Member Functions inherited from itk::Object | |
static bool | GetGlobalWarningDisplay () |
static void | GlobalWarningDisplayOff () |
static void | GlobalWarningDisplayOn () |
static Pointer | New () |
static void | SetGlobalWarningDisplay (bool val) |
Static Public Member Functions inherited from itk::LightObject | |
static void | BreakOnError () |
static Pointer | New () |
Protected Member Functions | |
double | FastNorm () |
NormalVariateGenerator () | |
void | PrintSelf (std::ostream &os, Indent indent) const override |
~NormalVariateGenerator () override | |
Protected Member Functions inherited from itk::Statistics::RandomVariateGeneratorBase | |
RandomVariateGeneratorBase () | |
~RandomVariateGeneratorBase () override | |
Protected Member Functions inherited from itk::Object | |
Object () | |
bool | PrintObservers (std::ostream &os, Indent indent) const |
void | PrintSelf (std::ostream &os, Indent indent) const override |
virtual void | SetTimeStamp (const TimeStamp &timeStamp) |
~Object () override | |
Protected Member Functions inherited from itk::LightObject | |
virtual LightObject::Pointer | InternalClone () const |
LightObject () | |
virtual void | PrintHeader (std::ostream &os, Indent indent) const |
virtual void | PrintSelf (std::ostream &os, Indent indent) const |
virtual void | PrintTrailer (std::ostream &os, Indent indent) const |
virtual | ~LightObject () |
Static Private Member Functions | |
static int | SignedShiftXOR (int irs) |
Private Attributes | |
double | m_ActualRSD {} |
double | m_Chic1 {} |
double | m_Chic2 {} |
int | m_Gaussfaze {} |
int * | m_Gausssave {} |
double | m_GScale {} |
int | m_Irs {} |
int | m_Lseed {} |
int | m_Nslew {} |
double | m_Rcons {} |
double | m_Rscale {} |
double | m_Scale {} |
int | m_Vec1 [m_TLEN] {} |
Static Private Attributes | |
static constexpr int | m_ELEN { 7 } |
static constexpr int | m_LEN { 128 } |
static constexpr int | m_LMASK { 4 * (m_LEN - 1) } |
static constexpr int | m_TLEN { 8 * m_LEN } |
Additional Inherited Members | |
Protected Attributes inherited from itk::LightObject | |
std::atomic< int > | m_ReferenceCount {} |
Definition at line 105 of file itkNormalVariateGenerator.h.
Definition at line 104 of file itkNormalVariateGenerator.h.
Standard class type aliases.
Definition at line 102 of file itkNormalVariateGenerator.h.
Definition at line 103 of file itkNormalVariateGenerator.h.
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protected |
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overrideprotected |
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protected |
get a variate
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overridevirtual |
Reimplemented from itk::Statistics::RandomVariateGeneratorBase.
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overridevirtual |
get a variate using FastNorm function
Implements itk::Statistics::RandomVariateGeneratorBase.
void itk::Statistics::NormalVariateGenerator::Initialize | ( | int | randomSeed | ) |
generate random number table
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static |
Method for creation through the object factory.
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overrideprotectedvirtual |
Methods invoked by Print() to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.
Reimplemented from itk::Object.
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inlinestaticprivate |
Definition at line 133 of file itkNormalVariateGenerator.h.
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private |
Definition at line 163 of file itkNormalVariateGenerator.h.
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Definition at line 161 of file itkNormalVariateGenerator.h.
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Definition at line 162 of file itkNormalVariateGenerator.h.
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staticconstexprprivate |
Definition at line 146 of file itkNormalVariateGenerator.h.
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Definition at line 152 of file itkNormalVariateGenerator.h.
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Definition at line 153 of file itkNormalVariateGenerator.h.
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Definition at line 155 of file itkNormalVariateGenerator.h.
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Definition at line 159 of file itkNormalVariateGenerator.h.
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staticconstexprprivate |
Definition at line 148 of file itkNormalVariateGenerator.h.
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staticconstexprprivate |
Definition at line 149 of file itkNormalVariateGenerator.h.
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Definition at line 160 of file itkNormalVariateGenerator.h.
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Definition at line 158 of file itkNormalVariateGenerator.h.
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Definition at line 144 of file itkNormalVariateGenerator.h.
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Definition at line 143 of file itkNormalVariateGenerator.h.
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Definition at line 142 of file itkNormalVariateGenerator.h.
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staticconstexprprivate |
Definition at line 150 of file itkNormalVariateGenerator.h.
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Definition at line 157 of file itkNormalVariateGenerator.h.