Class "adjacencyMatrix"

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Description

A class for adjacency matrix representation of simple-graphs

Objects from the Class

Objects can be created by calls of the form new("adjacencyMatrix",X).

Slots

.Data:

Object of class "matrix"; standard 0-1 coding for ordinary directed and undirected edges

Extends

Class "matrix", from data part. Class "structure", by class "matrix". Class "array", by class "matrix". Class "vector", by class "matrix", with explicit coerce.

Methods

initialize

signature(.Object = "adjacencyMatrix"): constructs an adjacency matrix representation of a simple-graph from a 0-1 matrix

show

signature(object = "adjacencyMatrix"): displays an adjacency matrix representation

names

signature(x = "adjacencyMatrix"): gets the character vertex identifiers of an adjacency matrix

names<-

signature(x = "adjacencyMatrix"): sets the character vertex identifiers of an adjacency matrix

card

signature(object = "adjacencyMatrix"): returns the number of vertices and the total number of edges (directed and undirected) in an incidence matrix

isEmpty

signature(object = "adjacencyMatrix"): an adjacency matrix is empty if it has no entries

isPresent

signature(el = "undirectedEdge", ou = "adjacencyMatrix"): tells whether an undirected edge occurs in the graph represented by an adjacency matrix

isPresent

signature(el = "directedEdge", ou = "adjacencyMatrix"): tells whether a directed edge occurs in the graph represented by an adjacency matrix

areTheSame

signature(x = "adjacencyMatrix", y = "adjacencyMatrix"): x and y are the same adjacency matrix if they represent the same simple-graph

[

signature(x = "adjacencyMatrix"): extracts the adjacency matrix of an induced subgraph

[[

signature(x = "adjacencyMatrix"): extracts the character identifier of a vertex

coerce

signature(from = "incidenceList", to = "adjacencyMatrix"): converts an incidence list to an adjacency matrix by keeping ordinary directed and undirected edges and dropping loops and parallel edges

coerce

signature(from = "incidenceMatrix", to = "adjacencyMatrix"): converts an incidence matrix to an adjacency matrix by dropping hyper-edges, loops and parallel edges

coerce

signature(from = "adjacencyList", to = "adjacencyMatrix"): converts an adjacency list to an adjacency matrix by dropping loops and parallel edges

+

signature(e1 = "adjacencyMatrix", e2 = "vertexSet"): adds a vertex set to an adjacency matrix by making the new vertices isolated

-

signature(e1 = "adjacencyMatrix", e2 = "vertexSet"): removes a vertex set from an adjacency matrix by dropping all edges involving the vertex set

+

signature(e1 = "adjacencyMatrix", e2 = "undirectedEdge"): adds an ordinary undirected edge (not a loop) to an adjacency matrix

+

signature(e1 = "adjacencyMatrix", e2 = "directedEdge"): adds an ordinary directed edge to an adjacency matrix

-

signature(e1 = "adjacencyMatrix", e2 = "undirectedEdge"): removes an undirected edge from an adjacency matrix

-

signature(e1 = "adjacencyMatrix", e2 = "directedEdge"): removes a directed edge from an adjacency matrix

*

signature(e1 = "adjacencyMatrix", e2 = "vertexSet"): restricts an adjacency matrix to a vertex set by dropping all edges involving vertices outside the vertex set

Warning

All input non-zero diagonal entries are silently changed to zero by the constructor.

Note

The names<- replacement method works only if the names to be assigned can be used to construct a vertexSet object having the right cardinality, otherwise the names are left unchanged and a warning message is given.

Author(s)

Jens Henrik Badsberg, Claus Dethlefsen, Luca La Rocca

See Also

adjacencyMatrix and simpleGraph-class