The triangular distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically. More...

#include <random-variable-stream.h>

Inheritance diagram for ns3::TriangularRandomVariable:

Collaboration diagram for ns3::TriangularRandomVariable:

Public Member Functions
	TriangularRandomVariable ()
	Creates a triangular distribution RNG with the default values for the mean, lower bound, and upper bound.
uint32_t	GetInteger (uint32_t mean, uint32_t min, uint32_t max)
	Returns a random unsigned integer from a triangular distribution with the specified mean, min, and max.
virtual uint32_t	GetInteger (void)
	Returns a random unsigned integer from a triangular distribution with the current mean, min, and max.
double	GetMax (void) const
	Returns the upper bound on values that can be returned by this RNG stream.
double	GetMean (void) const
	Returns the mean value for the triangular distribution returned by this RNG stream.
double	GetMin (void) const
	Returns the lower bound for the triangular distribution returned by this RNG stream.
double	GetValue (double mean, double min, double max)
	Returns a random double from a triangular distribution with the specified mean, min, and max.
virtual double	GetValue (void)
	Returns a random double from a triangular distribution with the current mean, min, and max.
Public Member Functions inherited from ns3::RandomVariableStream
	RandomVariableStream ()
virtual	~RandomVariableStream ()
int64_t	GetStream (void) const
	Returns the stream number for this RNG stream.
bool	IsAntithetic (void) const
	Returns true if antithetic values should be generated.
void	SetAntithetic (bool isAntithetic)
	Specifies whether antithetic values should be generated.
void	SetStream (int64_t stream)
	Specifies the stream number for this RNG stream.
Public Member Functions inherited from ns3::Object
	Object ()
virtual	~Object ()
void	AggregateObject (Ptr< Object > other)
void	Dispose (void)
AggregateIterator	GetAggregateIterator (void) const
virtual TypeId	GetInstanceTypeId (void) const
template<typename T >
Ptr< T >	GetObject (void) const
template<typename T >
Ptr< T >	GetObject (TypeId tid) const
void	Start (void)
Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
	SimpleRefCount ()
	SimpleRefCount (const SimpleRefCount &o)
uint32_t	GetReferenceCount (void) const
SimpleRefCount &	operator= (const SimpleRefCount &o)
void	Ref (void) const
void	Unref (void) const
Public Member Functions inherited from ns3::ObjectBase
virtual	~ObjectBase ()
void	GetAttribute (std::string name, AttributeValue &value) const
bool	GetAttributeFailSafe (std::string name, AttributeValue &attribute) const
void	SetAttribute (std::string name, const AttributeValue &value)
bool	SetAttributeFailSafe (std::string name, const AttributeValue &value)
bool	TraceConnect (std::string name, std::string context, const CallbackBase &cb)
bool	TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
bool	TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
bool	TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)

Static Public Member Functions
static TypeId	GetTypeId (void)
	This method returns the TypeId associated to ns3::TriangularRandomVariable.

Private Attributes
double	m_max
	The upper bound on values that can be returned by this RNG stream.
double	m_mean
	The mean value for the triangular distribution returned by this RNG stream.
double	m_min
	The lower bound on values that can be returned by this RNG stream.
double	m_mode

Additional Inherited Members
Protected Member Functions inherited from ns3::RandomVariableStream
RngStream *	Peek (void) const
	Returns a pointer to the underlying RNG stream.

Detailed Description

The triangular distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically.

This class supports the creation of objects that return random numbers from a fixed triangular distribution. It also supports the generation of single random numbers from various triangular distributions.

This distribution is a triangular distribution. The probability density is in the shape of a triangle.

Here is an example of how to use this class:

double mean = 5.0;
double min = 2.0;
double max = 10.0;
Ptr<TriangularRandomVariable> x = CreateObject<TriangularRandomVariable> ();
x->SetAttribute ("Mean", DoubleValue (mean));
x->SetAttribute ("Min", DoubleValue (min));
x->SetAttribute ("Max", DoubleValue (max));
// The expected value for the mean of the values returned by a
// triangularly distributed random variable is equal to mean.
double value = x->GetValue ();

Definition at line 1788 of file random-variable-stream.h.

Constructor & Destructor Documentation

ns3::TriangularRandomVariable::TriangularRandomVariable ( )

Creates a triangular distribution RNG with the default values for the mean, lower bound, and upper bound.

Definition at line 1090 of file random-variable-stream.cc.

Member Function Documentation

uint32_t ns3::TriangularRandomVariable::GetInteger	(	uint32_t	mean,
		uint32_t	min,
		uint32_t	max
	)

Returns a random unsigned integer from a triangular distribution with the specified mean, min, and max.

Parameters

mean	Mean value for the triangular distribution.
min	Low end of the range.
max	High end of the range.

Returns: A random unsigned integer value.

Note that antithetic values are being generated if m_isAntithetic is equal to true. If $u$ is a uniform variable over [0,1] and

$x = \left\{ \begin{array}{rl} min + \sqrt{u * (max - min) * (mode - min)} &\mbox{ if $u <= (mode - min)/(max - min)$} \\ max - \sqrt{ (1 - u) * (max - min) * (max - mode) } &\mbox{ otherwise} \end{array} \right.$

is a value that would be returned normally, where the mode or peak of the triangle is calculated as

$mode = 3.0 * mean - min - max .$

Then, $(1 - u$ ) is the distance that $u$ would be from $1$ . The value returned in the antithetic case, $x'$ , is calculated as

$x' = \left\{ \begin{array}{rl} min + \sqrt{(1 - u) * (max - min) * (mode - min)} &\mbox{ if $(1 - u) <= (mode - min)/(max - min)$} \\ max - \sqrt{ u * (max - min) * (max - mode) } &\mbox{ otherwise} \end{array} \right.$

which now involves the distance $u$ is from the 1.

Definition at line 1139 of file random-variable-stream.cc.

References GetValue().

Here is the call graph for this function:

uint32_t ns3::TriangularRandomVariable::GetInteger ( void )

virtual

Returns a random unsigned integer from a triangular distribution with the current mean, min, and max.

Returns: A random unsigned integer value.

Note that antithetic values are being generated if m_isAntithetic is equal to true. If $u$ is a uniform variable over [0,1] and

$x = \left\{ \begin{array}{rl} min + \sqrt{u * (max - min) * (mode - min)} &\mbox{ if $u <= (mode - min)/(max - min)$} \\ max - \sqrt{ (1 - u) * (max - min) * (max - mode) } &\mbox{ otherwise} \end{array} \right.$

is a value that would be returned normally, where the mode or peak of the triangle is calculated as

$mode = 3.0 * mean - min - max .$

Then, $(1 - u$ ) is the distance that $u$ would be from $1$ . The value returned in the antithetic case, $x'$ , is calculated as

$x' = \left\{ \begin{array}{rl} min + \sqrt{(1 - u) * (max - min) * (mode - min)} &\mbox{ if $(1 - u) <= (mode - min)/(max - min)$} \\ max - \sqrt{ u * (max - min) * (max - mode) } &\mbox{ otherwise} \end{array} \right.$

which now involves the distance $u$ is from the 1.

Implements ns3::RandomVariableStream.

Definition at line 1150 of file random-variable-stream.cc.

References GetValue(), m_max, m_mean, and m_min.

Here is the call graph for this function:

double ns3::TriangularRandomVariable::GetMax ( void ) const

Returns the upper bound on values that can be returned by this RNG stream.

Returns: The upper bound on values that can be returned by this RNG stream.

Definition at line 1109 of file random-variable-stream.cc.

References m_max.

double ns3::TriangularRandomVariable::GetMean ( void ) const

Returns the mean value for the triangular distribution returned by this RNG stream.

Returns: The mean value for the triangular distribution returned by this RNG stream.

Definition at line 1099 of file random-variable-stream.cc.

References m_mean.

double ns3::TriangularRandomVariable::GetMin ( void ) const

Returns the lower bound for the triangular distribution returned by this RNG stream.

Returns: The lower bound for the triangular distribution returned by this RNG stream.

Definition at line 1104 of file random-variable-stream.cc.

References m_min.

TypeId ns3::TriangularRandomVariable::GetTypeId ( void )

static

This method returns the TypeId associated to ns3::TriangularRandomVariable.

This object is accessible through the following paths with Config::Set and Config::Connect:

/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanDirection/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanPitch/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::GaussMarkovMobilityModel/MeanVelocity/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomDirection2dMobilityModel/Pause/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomDirection2dMobilityModel/Speed/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWalk2dMobilityModel/Direction/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWalk2dMobilityModel/Speed/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/Pause/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/X/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/Y/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomBoxPositionAllocator/Z/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomDiscPositionAllocator/Rho/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomDiscPositionAllocator/Theta/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomRectanglePositionAllocator/X/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/PositionAllocator/$ns3::RandomRectanglePositionAllocator/Y/$ns3::TriangularRandomVariable
/NodeList/[i]/$ns3::MobilityModel/$ns3::RandomWaypointMobilityModel/Speed/$ns3::TriangularRandomVariable
/NodeList/[i]/ApplicationList/[i]/$ns3::OnOffApplication/OffTime/$ns3::TriangularRandomVariable
/NodeList/[i]/ApplicationList/[i]/$ns3::OnOffApplication/OnTime/$ns3::TriangularRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::CsmaNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::TriangularRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::PointToPointNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::TriangularRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::SimpleNetDevice/ReceiveErrorModel/$ns3::RateErrorModel/RanVar/$ns3::TriangularRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::WifiNetDevice/Channel/$ns3::YansWifiChannel/PropagationDelayModel/$ns3::RandomPropagationDelayModel/Variable/$ns3::TriangularRandomVariable
/NodeList/[i]/DeviceList/[i]/$ns3::WifiNetDevice/Channel/$ns3::YansWifiChannel/PropagationLossModel/$ns3::RandomPropagationLossModel/Variable/$ns3::TriangularRandomVariable

Attributes defined for this type:

Mean: The mean value for the triangular distribution returned by this RNG stream.
- Set with class: ns3::DoubleValue
- Underlying type: double -1.79769e+308:1.79769e+308
- Initial value: 0.5
- Flags: construct write read
Min: The lower bound on the values returned by this RNG stream.
- Set with class: ns3::DoubleValue
- Underlying type: double -1.79769e+308:1.79769e+308
- Initial value: 0
- Flags: construct write read
Max: The upper bound on the values returned by this RNG stream.
- Set with class: ns3::DoubleValue
- Underlying type: double -1.79769e+308:1.79769e+308
- Initial value: 1
- Flags: construct write read

Attributes defined in parent class ns3::RandomVariableStream:

Stream: The stream number for this RNG stream. -1 means "allocate a stream automatically". Note that if -1 is set, Get will return -1 so that it is not possible to know which value was automatically allocated.
- Set with class: ns3::IntegerValue
- Underlying type: int64_t -9223372036854775808:9223372036854775807
- Initial value: -1
- Flags: construct write read
Antithetic: Set this RNG stream to generate antithetic values
- Set with class: BooleanValue
- Underlying type: bool
- Initial value: false
- Flags: construct write read

No TraceSources defined for this type.

Reimplemented from ns3::RandomVariableStream.

Definition at line 1070 of file random-variable-stream.cc.

References m_max, m_mean, m_min, and ns3::TypeId::SetParent().

Here is the call graph for this function:

double ns3::TriangularRandomVariable::GetValue	(	double	mean,
		double	min,
		double	max
	)

Returns a random double from a triangular distribution with the specified mean, min, and max.

Parameters

mean	Mean value for the triangular distribution.
min	Low end of the range.
max	High end of the range.

Returns: A floating point random value.

Note that antithetic values are being generated if m_isAntithetic is equal to true. If $u$ is a uniform variable over [0,1] and

$x = \left\{ \begin{array}{rl} min + \sqrt{u * (max - min) * (mode - min)} &\mbox{ if $u <= (mode - min)/(max - min)$} \\ max - \sqrt{ (1 - u) * (max - min) * (max - mode) } &\mbox{ otherwise} \end{array} \right.$

is a value that would be returned normally, where the mode or peak of the triangle is calculated as

$mode = 3.0 * mean - min - max .$

Then, $(1 - u$ ) is the distance that $u$ would be from $1$ . The value returned in the antithetic case, $x'$ , is calculated as

$x' = \left\{ \begin{array}{rl} min + \sqrt{(1 - u) * (max - min) * (mode - min)} &\mbox{ if $(1 - u) <= (mode - min)/(max - min)$} \\ max - \sqrt{ u * (max - min) * (max - mode) } &\mbox{ otherwise} \end{array} \right.$

which now involves the distance $u$ is from the 1.

Definition at line 1115 of file random-variable-stream.cc.

References ns3::RandomVariableStream::IsAntithetic(), ns3::RandomVariableStream::Peek(), and ns3::RngStream::RandU01().

Here is the call graph for this function:

double ns3::TriangularRandomVariable::GetValue ( void )

virtual

Returns a random double from a triangular distribution with the current mean, min, and max.

Returns: A floating point random value.

Note that antithetic values are being generated if m_isAntithetic is equal to true. If $u$ is a uniform variable over [0,1] and

$x = \left\{ \begin{array}{rl} min + \sqrt{u * (max - min) * (mode - min)} &\mbox{ if $u <= (mode - min)/(max - min)$} \\ max - \sqrt{ (1 - u) * (max - min) * (max - mode) } &\mbox{ otherwise} \end{array} \right.$

is a value that would be returned normally, where the mode or peak of the triangle is calculated as

$mode = 3.0 * mean - min - max .$

Then, $(1 - u$ ) is the distance that $u$ would be from $1$ . The value returned in the antithetic case, $x'$ , is calculated as

$x' = \left\{ \begin{array}{rl} min + \sqrt{(1 - u) * (max - min) * (mode - min)} &\mbox{ if $(1 - u) <= (mode - min)/(max - min)$} \\ max - \sqrt{ u * (max - min) * (max - mode) } &\mbox{ otherwise} \end{array} \right.$

which now involves the distance $u$ is from the 1.

Note that we have to re-implement this method here because the method is overloaded above for the three-argument variant and the c++ name resolution rules don't work well with overloads split between parent and child classes.

Implements ns3::RandomVariableStream.

Definition at line 1145 of file random-variable-stream.cc.

References m_max, m_mean, and m_min.

Referenced by GetInteger().

Here is the caller graph for this function: