TNGraph Class Reference

Directed graph. More...

List of all members.

Classes
class	TEdgeI
	Edge iterator. Only forward iteration (operator++) is supported. More...
class	TNode
class	TNodeI
	Node iterator. Only forward iteration (operator++) is supported. More...
Public Types
typedef TNGraph	TNet
typedef TPt< TNGraph >	PNet
Public Member Functions
	TNGraph ()
	TNGraph (const int &Nodes, const int &Edges)
	Constructor that reserves enough memory for a graph of Nodes nodes and Edges edges.
	TNGraph (const TNGraph &Graph)
	TNGraph (TSIn &SIn)
	Constructor that loads the graph from a (binary) stream SIn.
void	Save (TSOut &SOut) const
	Saves the graph to a (binary) stream SOut.
bool	HasFlag (const TGraphFlag &Flag) const
	Allows for run-time checking the type of the graph (see the TGraphFlag for flags).
TNGraph &	operator= (const TNGraph &Graph)
int	GetNodes () const
	Returns the number of nodes in the graph.
int	AddNode (int NId=-1)
	Adds a node of ID NId to the graph.
int	AddNode (const TNodeI &NodeId)
	Adds a node of ID NodeI.GetId() to the graph.
int	AddNode (const int &NId, const TIntV &InNIdV, const TIntV &OutNIdV)
	Adds a node of ID NId to the graph, creates edges to the node from all nodes in vector InNIdV, creates edges from the node to all nodes in vector OutNIdV.
int	AddNode (const int &NId, const TVecPool< TInt > &Pool, const int &SrcVId, const int &DstVId)
	Adds a node of ID NId to the graph, creates edges to the node from all nodes in vector InNIdV in the vector pool Pool, creates edges from the node to all nodes in vector OutNIdVin the vector pool Pool .
void	DelNode (const int &NId)
	Deletes node of ID NId from the graph.
void	DelNode (const TNode &NodeI)
	Deletes node of ID NodeI.GetId() from the graph.
bool	IsNode (const int &NId) const
	Tests whether ID NId is a node.
TNodeI	BegNI () const
	Returns an iterator referring to the first node in the graph.
TNodeI	EndNI () const
	Returns an iterator referring to the past-the-end node in the graph.
TNodeI	GetNI (const int &NId) const
	Returns an iterator referring to the node of ID NId in the graph.
int	GetMxNId () const
	Returns the maximum id of a any node in the graph.
int	GetEdges () const
	Returns the number of edges in the graph.
int	AddEdge (const int &SrcNId, const int &DstNId)
	Adds an edge from node IDs SrcNId to node DstNId to the graph.
int	AddEdge (const TEdgeI &EdgeI)
	Adds an edge from EdgeI.GetSrcNId() to EdgeI.GetDstNId() to the graph.
void	DelEdge (const int &SrcNId, const int &DstNId, const bool &IsDir=true)
	Deletes an edge from node IDs SrcNId to DstNId from the graph.
bool	IsEdge (const int &SrcNId, const int &DstNId, const bool &IsDir=true) const
	Tests whether an edge from node IDs SrcNId to DstNId exists in the graph.
TEdgeI	BegEI () const
	Returns an iterator referring to the first edge in the graph.
TEdgeI	EndEI () const
	Returns an iterator referring to the past-the-end edge in the graph.
TEdgeI	GetEI (const int &EId) const
	Not supported/implemented!
TEdgeI	GetEI (const int &SrcNId, const int &DstNId) const
	Returns an iterator referring to edge (SrcNId, DstNId) in the graph.
int	GetRndNId (TRnd &Rnd=TInt::Rnd)
	Returns an ID of a random node in the graph.
TNodeI	GetRndNI (TRnd &Rnd=TInt::Rnd)
	Returns an interator referring to a random node in the graph.
void	GetNIdV (TIntV &NIdV) const
	Gets a vector IDs of all nodes in the graph.
bool	Empty () const
	Tests whether the graph is empty (has zero nodes).
void	Clr ()
	Deletes all nodes and edges from the graph.
void	Reserve (const int &Nodes, const int &Edges)
	Reserves memory for a graph of Nodes nodes and Edges edges.
void	ReserveNIdInDeg (const int &NId, const int &InDeg)
	Reserves memory for node ID NId having InDeg in-edges.
void	ReserveNIdOutDeg (const int &NId, const int &OutDeg)
	Reserves memory for node ID NId having OutDeg out-edges.
void	Defrag (const bool &OnlyNodeLinks=false)
	Defragments the graph.
bool	IsOk (const bool &ThrowExcept=true) const
	Checks the graph data structure for internal consistency.
void	Dump (FILE *OutF=stdout) const
	Print the graph in a human readable form to an output stream OutF.
Static Public Member Functions
static PNGraph	New ()
	Static constructor that returns a pointer to the graph. Call: PNGraph Graph = TNGraph::New().
static PNGraph	New (const int &Nodes, const int &Edges)
	Static constructor that returns a pointer to the graph and reserves enough memory for Nodes nodes and Edges edges.
static PNGraph	Load (TSIn &SIn)
	Static constructor that loads the graph from a stream SIn and returns a pointer to it.
static PNGraph	GetSmallGraph ()
	Returns a small graph on 5 nodes and 6 edges.
Friends
class	TPt< TNGraph >
class	TNGraphMtx

---

Detailed Description

Directed graph.

Node IDs can be arbitrary non-negative integers. Nodes and edges have no attributes/data associated with them. There is at most one directed edge from one source node to a destination node. There can be an edge between the same pair of nodes in the opposite direction. Self loops (one per node) are allowed but multiple (parallel) edges are not. The directed graph data structure is implemented using sorted adjacency lists. This means adding a node takes constant time, while adding an edge takes linear time (since adjacency list is kept sorted) in the node degree. Accessing arbitrary node takes constant time and accessing any edge takes logarithmic time in the node degree.

---

Member Typedef Documentation

typedef TPt<TNGraph> TNGraph::PNet

typedef TNGraph TNGraph::TNet

---

Constructor & Destructor Documentation

TNGraph::TNGraph

(

)

[inline]

TNGraph::TNGraph	(	const int &	Nodes,
		const int &	Edges
	)		[inline, explicit]

Constructor that reserves enough memory for a graph of Nodes nodes and Edges edges.

TNGraph::TNGraph

(

const TNGraph &

Graph

)

[inline]

TNGraph::TNGraph

(

TSIn &

SIn

)

[inline]

Constructor that loads the graph from a (binary) stream SIn.

---

Member Function Documentation

int TNGraph::AddEdge	(	const int &	SrcNId,
		const int &	DstNId
	)

Adds an edge from node IDs SrcNId to node DstNId to the graph.

If the edge already exists return -2. If the edge was successfully added return -1. Normally the function should return an ID of the edge added but since edges in TNGraph have no IDs we return -1. Function aborts if SrcNId or DstNId are not nodes in the graph.

int TNGraph::AddEdge

(

const TEdgeI &

EdgeI

)

[inline]

Adds an edge from EdgeI.GetSrcNId() to EdgeI.GetDstNId() to the graph.

int TNGraph::AddNode

(

int

NId = -1

)

Adds a node of ID NId to the graph.

Returns the ID of the node being added. If NId is -1, node ID is automatically assigned. Aborts, if a node with ID NId already exists.

int TNGraph::AddNode

(

const TNodeI &

NodeId

)

[inline]

Adds a node of ID NodeI.GetId() to the graph.

int TNGraph::AddNode	(	const int &	NId,
		const TIntV &	InNIdV,
		const TIntV &	OutNIdV
	)

Adds a node of ID NId to the graph, creates edges to the node from all nodes in vector InNIdV, creates edges from the node to all nodes in vector OutNIdV.

Returns the ID of the node being added. If NId is -1, node ID is automatically assigned. Aborts, if a node with ID NId already exists.

The operation can create inconsistent graphs when the neighboring nodes in vectors InNIdV and OutNIdV do not exist. Use TNGraph::IsOk to check that the resulting graph is consistent after the operation.

int TNGraph::AddNode	(	const int &	NId,
		const TVecPool< TInt > &	Pool,
		const int &	SrcVId,
		const int &	DstVId
	)

Adds a node of ID NId to the graph, creates edges to the node from all nodes in vector InNIdV in the vector pool Pool, creates edges from the node to all nodes in vector OutNIdVin the vector pool Pool .

Returns the ID of the node being added. If NId is -1, node ID is automatically assigned. Aborts, if a node with ID NId already exists.

The operation can create inconsistent graphs when the neighboring nodes stored in the Pool vector are not explicitly added to the graph. Use TNGraph::IsOk to check that the resulting graph is consistent.

TEdgeI TNGraph::BegEI

(

)

const [inline]

Returns an iterator referring to the first edge in the graph.

TNodeI TNGraph::BegNI

(

)

const [inline]

Returns an iterator referring to the first node in the graph.

void TNGraph::Clr

(

)

[inline]

Deletes all nodes and edges from the graph.

void TNGraph::Defrag

(

const bool &

OnlyNodeLinks = false

)

Defragments the graph.

After performing many node and edge insertions and deletions to a graph, the graph data structure will be fragmented in memory. This function compacts down the graph data structure and frees unneeded memory.

void TNGraph::DelEdge	(	const int &	SrcNId,
		const int &	DstNId,
		const bool &	IsDir = true
	)

Deletes an edge from node IDs SrcNId to DstNId from the graph.

If the edge (SrcNId, DstNId) does not exist in the graph function still completes. But the function aborts if SrcNId or DstNId are not nodes in the graph.

void TNGraph::DelNode

(

const int &

NId

)

Deletes node of ID NId from the graph.

If the node of ID NId does not exist the function aborts.

void TNGraph::DelNode

(

const TNode &

NodeI

)

[inline]

Deletes node of ID NodeI.GetId() from the graph.

void TNGraph::Dump

(

FILE *

OutF = stdout

)

const

Print the graph in a human readable form to an output stream OutF.

bool TNGraph::Empty

(

)

const [inline]

Tests whether the graph is empty (has zero nodes).

TEdgeI TNGraph::EndEI

(

)

const [inline]

Returns an iterator referring to the past-the-end edge in the graph.

TNodeI TNGraph::EndNI

(

)

const [inline]

Returns an iterator referring to the past-the-end node in the graph.

int TNGraph::GetEdges

(

)

const

Returns the number of edges in the graph.

TEdgeI TNGraph::GetEI

(

const int &

EId

)

const

Not supported/implemented!

TNGraph::TEdgeI TNGraph::GetEI	(	const int &	SrcNId,
		const int &	DstNId
	)		const

Returns an iterator referring to edge (SrcNId, DstNId) in the graph.

int TNGraph::GetMxNId

(

)

const [inline]

Returns the maximum id of a any node in the graph.

TNodeI TNGraph::GetNI

(

const int &

NId

)

const [inline]

Returns an iterator referring to the node of ID NId in the graph.

void TNGraph::GetNIdV

(

TIntV &

NIdV

)

const

Gets a vector IDs of all nodes in the graph.

int TNGraph::GetNodes

(

)

const [inline]

Returns the number of nodes in the graph.

TNodeI TNGraph::GetRndNI

(

TRnd &

Rnd = TInt::Rnd

)

[inline]

Returns an interator referring to a random node in the graph.

int TNGraph::GetRndNId

(

TRnd &

Rnd = TInt::Rnd

)

[inline]

Returns an ID of a random node in the graph.

PNGraph TNGraph::GetSmallGraph

(

)

[static]

Returns a small graph on 5 nodes and 6 edges.

  * Edges:  0 -> 1, 1 -> 2, 0 -> 2, 1 -> 3, 3 -> 4, 2 -> 3
  * 

bool TNGraph::HasFlag

(

const TGraphFlag &

Flag

)

const

Allows for run-time checking the type of the graph (see the TGraphFlag for flags).

bool TNGraph::IsEdge	(	const int &	SrcNId,
		const int &	DstNId,
		const bool &	IsDir = true
	)		const

Tests whether an edge from node IDs SrcNId to DstNId exists in the graph.

bool TNGraph::IsNode

(

const int &

NId

)

const [inline]

Tests whether ID NId is a node.

bool TNGraph::IsOk

(

const bool &

ThrowExcept = true

)

const

Checks the graph data structure for internal consistency.

For each node in the graph check that its neighbors are also nodes in the graph.

static PNGraph TNGraph::Load

(

TSIn &

SIn

)

[inline, static]

Static constructor that loads the graph from a stream SIn and returns a pointer to it.

static PNGraph TNGraph::New

(

)

[inline, static]

Static constructor that returns a pointer to the graph. Call: PNGraph Graph = TNGraph::New().

static PNGraph TNGraph::New	(	const int &	Nodes,
		const int &	Edges
	)		[inline, static]

Static constructor that returns a pointer to the graph and reserves enough memory for Nodes nodes and Edges edges.

Call: PNGraph Graph = TNGraph::New(Nodes, Edges).

TNGraph& TNGraph::operator=

(

const TNGraph &

Graph

)

[inline]

void TNGraph::Reserve	(	const int &	Nodes,
		const int &	Edges
	)		[inline]

Reserves memory for a graph of Nodes nodes and Edges edges.

void TNGraph::ReserveNIdInDeg	(	const int &	NId,
		const int &	InDeg
	)		[inline]

Reserves memory for node ID NId having InDeg in-edges.

void TNGraph::ReserveNIdOutDeg	(	const int &	NId,
		const int &	OutDeg
	)		[inline]

Reserves memory for node ID NId having OutDeg out-edges.

void TNGraph::Save

(

TSOut &

SOut

)

const [inline]

Saves the graph to a (binary) stream SOut.

---

Friends And Related Function Documentation

friend class TNGraphMtx [friend]

friend class TPt< TNGraph > [friend]

---

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

• snap-core/graph.h
• snap-core/graph.cpp