mty::wick::Vertex Class Reference

Represents a Vertex in feynman diagrams, i.e. a set of Nodes at the same space-time point. More...

#include <graph.h>

Inheritance diagram for mty::wick::Vertex:

Public Member Functions
	Vertex ()
	Default constructor, initializes an empty Vertex.
	Vertex (const std::vector< const mty::QuantumField *> &fields, size_t id, bool t_external=false)
	Constructor with 2 parameters. More...
	Vertex (const Vertex &other)
	Copy constructor. See Vertex::operator=().
bool	isExternal () const
bool	isFree () const
bool	hasFreeNode () const
bool	hasFreeNode (const mty::QuantumField *field) const
	Tells if a Vertex can be contracted with (has free nodes for) a particular mty::QuantumField. More...
bool	containsExplicit (const mty::QuantumField *field) const
bool	isDegenerateWith (const Vertex &other) const
	Tells if the Vertex is degenerate with another. More...
const mty::QuantumField *	getFirstContractibleField () const
	Returns the field associated to the first contractible Node of the Vertex. This function calls an error if the Vertex is fully contracted. More...
std::shared_ptr< Node >	getFirstContractibleNode () const
std::shared_ptr< Node >	getFirstContractibleNode (const mty::QuantumField *field) const
	Returns the first Node contractible with field if there is one. More...
std::vector< std::shared_ptr< Node > >	getContractibleNodes () const
std::vector< std::shared_ptr< Node > >	getContractibleNodes (const mty::QuantumField *field) const
void	setExternal (bool t_external)
	Sets the external property of the Vertex. True means that the Vertex is composed of field insertions.
int	getDegeneracy (const mty::QuantumField *t_field) const
	Computes and returns the degeneracy of the Vertex with respect to a given mty::QuantumField. The degeneracy is the number of free Nodes contractible with field. See isExactlyContractiblewith(). More...
int	getTotalDegeneracyFactor () const
Vertex &	operator= (const Vertex &other)
	Overload of operator= for Vertex. More...
bool	operator== (const Vertex &other) const
	Overload of operator== for Vertex. More...
bool	operator!= (const Vertex &other) const
	Overload of operator!= for Vertex. See Vertex::operator==(). More...

Protected Attributes
bool	external
	Tells if the Vertex is external, i.e. composed of field insertions.
size_t	id

Friends
std::ostream &	operator<< (std::ostream &fout, const Vertex &v)
	Overload of operator<< for Vertex. More...

Detailed Description

Represents a Vertex in feynman diagrams, i.e. a set of Nodes at the same space-time point.

Constructor & Destructor Documentation

Vertex()

mty::wick::Vertex::Vertex ( const std::vector< const mty::QuantumField *> &  fields, size_t  id, bool  t_external = false  )

explicit

Constructor with 2 parameters.

Parameters

fields	std::vector of mty::QuantumField in the Vertex.
t_external	Tells if the vertex is external (field insertion in correlator).

Member Function Documentation

getContractibleNodes()

vector< shared_ptr< Node > > mty::wick::Vertex::getContractibleNodes

(

)

const

Returns

A std::vector filled with all contractible Node objects in the Vertex.

getDegeneracy()

int mty::wick::Vertex::getDegeneracy

(

const mty::QuantumField *

t_field

)

const

Computes and returns the degeneracy of the Vertex with respect to a given mty::QuantumField. The degeneracy is the number of free Nodes contractible with field. See isExactlyContractiblewith().

Parameters

t_field

mty::QuantumField we want to contract.

Returns

The number of free Node contractible with field.

getFirstContractibleField()

const QuantumField * mty::wick::Vertex::getFirstContractibleField

(

)

const

Returns the field associated to the first contractible Node of the Vertex. This function calls an error if the Vertex is fully contracted.

Returns

The mty::QuantumField of the first contractible Node.

getFirstContractibleNode() [1/2]

shared_ptr< Node > mty::wick::Vertex::getFirstContractibleNode

(

)

const

Returns

A shared_ptr to the the first constractible Node if ther is one.

nullptr else.

getFirstContractibleNode() [2/2]

shared_ptr< Node > mty::wick::Vertex::getFirstContractibleNode

(

const mty::QuantumField *

field

)

const

Returns the first Node contractible with field if there is one.

Parameters

field

mty::QuantumField we want to contract.

Returns

A shared_ptr to the the first Node contractible with field if ther is one.

nullptr else.

hasFreeNode() [1/2]

bool mty::wick::Vertex::hasFreeNode

(

)

const

Returns

True if the Vertex has at least one free Node.

False else.

hasFreeNode() [2/2]

bool mty::wick::Vertex::hasFreeNode

(

const mty::QuantumField *

field

)

const

Tells if a Vertex can be contracted with (has free nodes for) a particular mty::QuantumField.

Parameters

field

mty::QuantumField we want to contract.

Returns

True if the Vertex has at least one contractible Node with field (see isExactlyContractiblewith()).

isDegenerateWith()

bool mty::wick::Vertex::isDegenerateWith

(

const Vertex &

other

)

const

Tells if the Vertex is degenerate with another.

Returns

True if the two vertices have the same field content.

False else.

isExternal()

bool mty::wick::Vertex::isExternal

(

)

const

Returns

external (i.e. if the Vertex comes from field insertions).

isFree()

bool mty::wick::Vertex::isFree

(

)

const

Returns

True if the Vertex is free, i.e. has no contraction.

False else.

operator!=()

bool mty::wick::Vertex::operator!=

(

const Vertex &

other

)

const

Overload of operator!= for Vertex. See Vertex::operator==().

Returns

False if the field contents are identical.

True else.

operator=()

Vertex & mty::wick::Vertex::operator=

(

const Vertex &

other

)

Overload of operator= for Vertex.

A little subtlety lies there. Nodes that are already contracted are not really copied, i.e. only the shared_ptr are copied. In that case the two final vertices have a pointer to the same Node in memory. This is because in the contraction algorithm, a contracted Node do not change at all after that. However, free nodes are really copied (the two Vertices have two different Nodes) because in two different graphs, the two Nodes can be contracted with different possible partners, and then will be different.

Parameters

other

Vertex to copy.

Returns

A reference to the modified Vertex.

operator==()

bool mty::wick::Vertex::operator==

(

const Vertex &

other

)

const

Overload of operator== for Vertex.

Tells if the field content is the same and in the same order.

Parameters

other

Vertex to compare.

Returns

True if the field contents are identical.

False else.

Friends And Related Function Documentation

operator<<

std::ostream& operator<< ( std::ostream &  fout, const Vertex &  v  )

friend

Overload of operator<< for Vertex.

Parameters

fout	Output stream.
v	Vertex to display.

Returns

The modified stream.

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

• include/graph.h
• src/graph.cpp