ThePEG::MEBase Class Reference

The MEBase class is the base class of all objects representing hard matrix elements in ThePEG. More...

#include <MEBase.h>

Inheritance diagram for ThePEG::MEBase:

List of all members.

Public Types

typedef vector< DiagPtr > DiagramVector

A vector of pointers to DiagramBase objects.

typedef DiagramVector::size_type DiagramIndex

The size_type used in the DiagramVector.

typedef vector< ReweightPtr > ReweightVector

A vector of pointers to ReweightBase objects.

Public Member Functions

Standard constructors and destructors.

MEBase ()

Default constructor.

virtual ~MEBase ()

Destructor.

Virtual functions to be overridden by sub-classes..

virtual unsigned int orderInAlphaS () const =0

Return the order in $\alpha_S$ in which this matrix element is given.

virtual unsigned int orderInAlphaEW () const =0

Return the order in $\alpha_{EM}$ in which this matrix element is given.

virtual double me2 () const =0

Return the matrix element for the kinematical configuation previously provided by the last call to setKinematics(), suitably scaled by sHat() to give a dimension-less number.

virtual Energy2 scale () const =0

Return the scale associated with the phase space point provided by the last call to setKinematics().

virtual double alphaS () const

Return the value of $\alpha_S$ associated with the phase space point provided by the last call to setKinematics().

virtual double alphaEM () const

Return the value of $\alpha_EM$ associated with the phase space point provided by the last call to setKinematics().

void setKinematics (tPPair in, const PVector &out)

Set the typed and momenta of the incoming and outgoing partons to be used in subsequent calls to me() and colourGeometries().

virtual void setKinematics ()

Set the typed and momenta of the incoming and outgoing partons to be used in subsequent calls to me() and colourGeometries() according to the associated XComb object.

virtual void constructVertex (tSubProPtr sub)

construct the spin information for the interaction

virtual int nDim () const

The number of internal degreed of freedom used in the matrix element.

virtual bool generateKinematics (const double *r)=0

Generate internal degrees of freedom given nDim() uniform random numbers in the interval ]0,1[.

virtual CrossSection dSigHatDR () const =0

Return the matrix element squared differential in the variables given by the last call to generateKinematics().

virtual void generateSubCollision (SubProcess &)

Comlete a SubProcess object using the internal degrees of freedom generated in the last generateKinematics() (and possible other degrees of freedom which was intergated over in dSigHatDR().

virtual void clearKinematics ()

Clear the information previously provided by a call to setKinematics(.

virtual void getDiagrams () const =0

Add all possible diagrams with the add() function.

const DiagramVector & diagrams () const

Return all possible diagrams.

virtual Selector< const
ColourLines * > colourGeometries (tcDiagPtr diag) const =0

Return a Selector with possible colour geometries for the selected diagram weighted by their relative probabilities.

virtual const ColourLines & selectColourGeometry (tcDiagPtr diag) const

Select a ColpurLines geometry.

virtual Selector< DiagramIndex > diagrams (const DiagramVector &) const

With the information previously supplied with the setKinematics(.

virtual DiagramIndex diagram (const DiagramVector &) const

Select a diagram.

bool reweighted () const

Return true if this matrix element has associated (p)reWeight objects assigned.

double reWeight () const

With the information previously supplied with the setKinematics(.

double preWeight () const

With the information previously supplied with the setKinematics(.

void addReweighter (tReweightPtr rw)

Add objects to the list of reweighters.

void addPreweighter (tReweightPtr rw)

Add objects to the list of preweighters.

Ptr< Amplitude >::pointer amplitude () const

Return the amplitude associated with this matrix element.

Acces information about the last generated phase space point.

Energy2 sHat () const

Return the last set invariant mass squared.

double preweight () const

Return the factor with which this matrix element was last pre-weighted.

virtual void setXComb (tStdXCombPtr)

Set the XComb object to be used in the next call to generateKinematics() and dSigHatDR().

const DVector & meInfo () const

Retrieve information obtained in the calculation of the cross section to be used later when selecting diagrams and colour flow.

void meInfo (const DVector &info) const

Save information obtained in the calculation of the cross section to be used later when selecting diagrams and colour flow.

int maxMultCKKW () const

If this matrix element is to be used together with others for CKKW reweighting and veto, this should give the multiplicity of outgoing particles in the highest multiplicity matrix element in the group.

int minMultCKKW () const

If this matrix element is to be used together with others for CKKW reweighting and veto, this should give the multiplicity of outgoing particles in the lowest multiplicity matrix element in the group.

Functions used by the persistent I/O system.

void persistentOutput (PersistentOStream &os) const

Function used to write out object persistently.

void persistentInput (PersistentIStream &is, int version)

Function used to read in object persistently.

Static Public Member Functions

static void Init ()

Standard Init function used to initialize the interfaces.

Protected Member Functions

void add (DiagPtr dp) const

To be used by sub classes in the getDiagrams() method to add included diagrams.

vector< Lorentz5Momentum > & meMomenta ()

Access the momenta set by the last call to generateKinematics().

double jacobian () const

Get the last jacobian obtained when generating the kinematics for the call to dSigHatDR.

void jacobian (double j)

Set the last jacobian obtained when generating the kinematics for the call to dSigHatDR.

Private Member Functions

MEBase & operator= (const MEBase &)

Private and non-existent assignment operator.

Private Attributes

DiagramVector theDiagrams

The diagrams included for this matrix element.

Energy2 theLastSHat

The last set invariant mass squared.

ReweightVector reweights

The reweight objects modifying this matrix element.

ReweightVector preweights

The preweight objects modifying this matrix element.

double lastPreweight

The factor with which this matrix element was last pre-weighted.

Ptr< Amplitude >::pointer theAmplitude

The amplitude associated with this matrix element.

double theLastJacobian

Save the last jacobian obtained when generating the kinematics for the call to dSigHatDR.

int theMaxMultCKKW

If this matrix element is to be used together with others for CKKW reweighting and veto, this should give the multiplicity of outgoing particles in the highest multiplicity matrix element in the group.

int theMinMultCKKW

If this matrix element is to be used together with others for CKKW reweighting and veto, this should give the multiplicity of outgoing particles in the lowest multiplicity matrix element in the group.

Static Private Attributes

static
AbstractClassDescription
< MEBase > initMEBase

Describe an abstract base class with persistent data.

Detailed Description

The MEBase class is the base class of all objects representing hard matrix elements in ThePEG.

There are three methods which must be overridden by a concrete subclass:

includedDiagrams(tcPDPair) should return a vector of DiagramBase objects describing the diagrams used for this matrix element for the given pair of incoming parton types. These DiagramBases are used to identify the incoming and outgoing partons which can be handled by the process generation scheme, and is also used to cnstruct a corresponding SubProcess object.

scale() should return the scale associated with the phase space point set with the last call to setKinematics(...) or generateKinematics(...).

me() should return the the matrix element squared using the the type and momentum of the incoming and outgoing partons, previously set by the setKinematics(...) or generateKinematics(...) member functions, accessible through the methods meMomenta() and mePartonData() inherited from LastXCombInfo, and/or from information stored by sub classes. The returned value should be dimensionless suitable scaled by the total invariant mass squared (accessible through the sHat() member function). Any user of this method must make sure that the setKinematics(...) member function has been appropriately called before.

colourGeometries() should return a Selector with the possible ColourLines objects weighted by their relative probabilities given the information set by the last call to setKinematics(...) or generateKinematics(...).

There are other virtula functions which may be overridden as listed below.

See also:

The interfaces defined for MEBase.

DiagramBase

ColourLines

Definition at line 67 of file MEBase.h.

Member Typedef Documentation

typedef vector<DiagPtr> ThePEG::MEBase::DiagramVector

A vector of pointers to DiagramBase objects.

Definition at line 72 of file MEBase.h.

typedef DiagramVector::size_type ThePEG::MEBase::DiagramIndex

The size_type used in the DiagramVector.

Definition at line 74 of file MEBase.h.

typedef vector<ReweightPtr> ThePEG::MEBase::ReweightVector

A vector of pointers to ReweightBase objects.

Definition at line 76 of file MEBase.h.

Member Function Documentation

virtual unsigned int ThePEG::MEBase::orderInAlphaEW ( ) const [pure virtual]

Return the order in $\alpha_{EM}$ in which this matrix element is given.

Returns 0.

Implemented in ThePEG::ME2to2QCD, ThePEG::MEee2gZ2qq, and ThePEG::MENCDIS.

virtual double ThePEG::MEBase::alphaS ( ) const [virtual]

Return the value of $\alpha_S$ associated with the phase space point provided by the last call to setKinematics().

This versions returns SM().alphaS(scale()).

virtual double ThePEG::MEBase::alphaEM ( ) const [virtual]

Return the value of $\alpha_EM$ associated with the phase space point provided by the last call to setKinematics().

This versions returns SM().alphaEM(scale()).

virtual void ThePEG::MEBase::setKinematics ( ) [virtual]

Set the typed and momenta of the incoming and outgoing partons to be used in subsequent calls to me() and colourGeometries() according to the associated XComb object.

If the function is overridden in a sub class the new function must call the base class one first.

Reimplemented in ThePEG::ME2to2Base.

virtual int ThePEG::MEBase::nDim ( ) const [virtual]

The number of internal degreed of freedom used in the matrix element.

This default version returns 0;

Reimplemented in ThePEG::ME2to2Base.

virtual bool ThePEG::MEBase::generateKinematics ( const double * r ) [pure virtual]

Generate internal degrees of freedom given nDim() uniform random numbers in the interval ]0,1[.

To help the phase space generator, the 'dSigHatDR' should be a smooth function of these numbers, although this is not strictly necessary. The return value should be true of the generation succeeded. If so the generated momenta should be stored in the meMomenta() vector.

Implemented in ThePEG::ME2to2Base.

virtual void ThePEG::MEBase::generateSubCollision ( SubProcess & ) [virtual]

Comlete a SubProcess object using the internal degrees of freedom generated in the last generateKinematics() (and possible other degrees of freedom which was intergated over in dSigHatDR().

This default version does nothing. Will be made purely virtual in the future.

virtual void ThePEG::MEBase::clearKinematics ( ) [virtual]

Clear the information previously provided by a call to setKinematics(.

..).

virtual const ColourLines& ThePEG::MEBase::selectColourGeometry ( tcDiagPtr diag ) const [virtual]

Select a ColpurLines geometry.

The default version returns a colour geometry selected among the ones returned from colourGeometries(tcDiagPtr).

virtual Selector<DiagramIndex> ThePEG::MEBase::diagrams ( const DiagramVector & ) const [inline, virtual]

With the information previously supplied with the setKinematics(.

..) method, a derived class may optionally override this method to weight the given diagrams with their (although certainly not physical) relative probabilities.

Reimplemented in ThePEG::MEee2gZ2qq, ThePEG::MEGG2GG, ThePEG::MEGG2QQ, ThePEG::MENCDIS, ThePEG::MEQG2QG, ThePEG::MEQQ2GG, ThePEG::MEqq2qq, ThePEG::MEQQ2qq, ThePEG::MEQQ2QQ, and ThePEG::MEQq2Qq.

Definition at line 227 of file MEBase.h.

virtual DiagramIndex ThePEG::MEBase::diagram ( const DiagramVector & ) const [virtual]

Select a diagram.

Default version uses diagrams(const DiagramVector &) to select a diagram according to the weights. This is the only method used that should be outside of MEBase.

double ThePEG::MEBase::reWeight ( ) const

With the information previously supplied with the setKinematics(.

..) methods, return the combined effects of the reweighters.

double ThePEG::MEBase::preWeight ( ) const

With the information previously supplied with the setKinematics(.

..) methods, return the comined effects of the peweighters.

Ptr<Amplitude>::pointer ThePEG::MEBase::amplitude ( ) const [inline]

Return the amplitude associated with this matrix element.

This function is allowed to return the null pointer if the amplitude is not available.

Definition at line 277 of file MEBase.h.

References theAmplitude.

void ThePEG::MEBase::persistentOutput ( PersistentOStream & os ) const

Function used to write out object persistently.

Parameters:

os

the persistent output stream written to.

Reimplemented from ThePEG::Interfaced.

Reimplemented in ThePEG::ME2to2Base, ThePEG::ME2to2QCD, ThePEG::MEee2gZ2qq, and ThePEG::MENCDIS.

void ThePEG::MEBase::persistentInput	(	PersistentIStream &	is,
		int	version
	)

Function used to read in object persistently.

Parameters:

	is	the persistent input stream read from.
	version	the version number of the object when written.

Reimplemented from ThePEG::Interfaced.

Reimplemented in ThePEG::ME2to2Base, ThePEG::ME2to2QCD, ThePEG::MEee2gZ2qq, and ThePEG::MENCDIS.

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

MEBase.h


Public Types
typedef vector< DiagPtr >	DiagramVector
	A vector of pointers to DiagramBase objects.
typedef DiagramVector::size_type	DiagramIndex
	The size_type used in the DiagramVector.
typedef vector< ReweightPtr >	ReweightVector
	A vector of pointers to ReweightBase objects.
Public Member Functions
Standard constructors and destructors.
	MEBase ()
	Default constructor.
virtual	~MEBase ()
	Destructor.
Virtual functions to be overridden by sub-classes..
virtual unsigned int	orderInAlphaS () const =0
	Return the order in $\alpha_S$ in which this matrix element is given.
virtual unsigned int	orderInAlphaEW () const =0
	Return the order in $\alpha_{EM}$ in which this matrix element is given.
virtual double	me2 () const =0
	Return the matrix element for the kinematical configuation previously provided by the last call to setKinematics(), suitably scaled by sHat() to give a dimension-less number.
virtual Energy2	scale () const =0
	Return the scale associated with the phase space point provided by the last call to setKinematics().
virtual double	alphaS () const
	Return the value of $\alpha_S$ associated with the phase space point provided by the last call to setKinematics().
virtual double	alphaEM () const
	Return the value of $\alpha_EM$ associated with the phase space point provided by the last call to setKinematics().
void	setKinematics (tPPair in, const PVector &out)
	Set the typed and momenta of the incoming and outgoing partons to be used in subsequent calls to me() and colourGeometries().
virtual void	setKinematics ()
	Set the typed and momenta of the incoming and outgoing partons to be used in subsequent calls to me() and colourGeometries() according to the associated XComb object.
virtual void	constructVertex (tSubProPtr sub)
	construct the spin information for the interaction
virtual int	nDim () const
	The number of internal degreed of freedom used in the matrix element.
virtual bool	generateKinematics (const double *r)=0
	Generate internal degrees of freedom given nDim() uniform random numbers in the interval ]0,1[.
virtual CrossSection	dSigHatDR () const =0
	Return the matrix element squared differential in the variables given by the last call to generateKinematics().
virtual void	generateSubCollision (SubProcess &)
	Comlete a SubProcess object using the internal degrees of freedom generated in the last generateKinematics() (and possible other degrees of freedom which was intergated over in dSigHatDR().
virtual void	clearKinematics ()
	Clear the information previously provided by a call to setKinematics(.
virtual void	getDiagrams () const =0
	Add all possible diagrams with the add() function.
const DiagramVector &	diagrams () const
	Return all possible diagrams.
virtual Selector< const ColourLines * >	colourGeometries (tcDiagPtr diag) const =0
	Return a Selector with possible colour geometries for the selected diagram weighted by their relative probabilities.
virtual const ColourLines &	selectColourGeometry (tcDiagPtr diag) const
	Select a ColpurLines geometry.
virtual Selector< DiagramIndex >	diagrams (const DiagramVector &) const
	With the information previously supplied with the setKinematics(.
virtual DiagramIndex	diagram (const DiagramVector &) const
	Select a diagram.
bool	reweighted () const
	Return true if this matrix element has associated (p)reWeight objects assigned.
double	reWeight () const
	With the information previously supplied with the setKinematics(.
double	preWeight () const
	With the information previously supplied with the setKinematics(.
void	addReweighter (tReweightPtr rw)
	Add objects to the list of reweighters.
void	addPreweighter (tReweightPtr rw)
	Add objects to the list of preweighters.
Ptr< Amplitude >::pointer	amplitude () const
	Return the amplitude associated with this matrix element.
Acces information about the last generated phase space point.
Energy2	sHat () const
	Return the last set invariant mass squared.
double	preweight () const
	Return the factor with which this matrix element was last pre-weighted.
virtual void	setXComb (tStdXCombPtr)
	Set the XComb object to be used in the next call to generateKinematics() and dSigHatDR().
const DVector &	meInfo () const
	Retrieve information obtained in the calculation of the cross section to be used later when selecting diagrams and colour flow.
void	meInfo (const DVector &info) const
	Save information obtained in the calculation of the cross section to be used later when selecting diagrams and colour flow.
int	maxMultCKKW () const
	If this matrix element is to be used together with others for CKKW reweighting and veto, this should give the multiplicity of outgoing particles in the highest multiplicity matrix element in the group.
int	minMultCKKW () const
	If this matrix element is to be used together with others for CKKW reweighting and veto, this should give the multiplicity of outgoing particles in the lowest multiplicity matrix element in the group.
Functions used by the persistent I/O system.
void	persistentOutput (PersistentOStream &os) const
	Function used to write out object persistently.
void	persistentInput (PersistentIStream &is, int version)
	Function used to read in object persistently.
Static Public Member Functions
static void	Init ()
	Standard Init function used to initialize the interfaces.
Protected Member Functions
void	add (DiagPtr dp) const
	To be used by sub classes in the getDiagrams() method to add included diagrams.
vector< Lorentz5Momentum > &	meMomenta ()
	Access the momenta set by the last call to generateKinematics().
double	jacobian () const
	Get the last jacobian obtained when generating the kinematics for the call to dSigHatDR.
void	jacobian (double j)
	Set the last jacobian obtained when generating the kinematics for the call to dSigHatDR.
Private Member Functions
MEBase &	operator= (const MEBase &)
	Private and non-existent assignment operator.
Private Attributes
DiagramVector	theDiagrams
	The diagrams included for this matrix element.
Energy2	theLastSHat
	The last set invariant mass squared.
ReweightVector	reweights
	The reweight objects modifying this matrix element.
ReweightVector	preweights
	The preweight objects modifying this matrix element.
double	lastPreweight
	The factor with which this matrix element was last pre-weighted.
Ptr< Amplitude >::pointer	theAmplitude
	The amplitude associated with this matrix element.
double	theLastJacobian
	Save the last jacobian obtained when generating the kinematics for the call to dSigHatDR.
int	theMaxMultCKKW
	If this matrix element is to be used together with others for CKKW reweighting and veto, this should give the multiplicity of outgoing particles in the highest multiplicity matrix element in the group.
int	theMinMultCKKW
	If this matrix element is to be used together with others for CKKW reweighting and veto, this should give the multiplicity of outgoing particles in the lowest multiplicity matrix element in the group.
Static Private Attributes
static AbstractClassDescription < MEBase >	initMEBase
	Describe an abstract base class with persistent data.