Provided by: afnix_2.2.0-2ubuntu1_amd64 
NAME
gfx - standard graph module
STANDARD GRAPH MODULE
The Standard Graph module is an original implementation dedicated to the graph moddeling and
manipulation. At the heart of this module is the concept of edges and vertices.
Graph concepts
The afnix-gfx module provides the support for manipulating graphs. Formally a graph is a collection of
edges and vertices. In a normal graph, an edge connects two vertices. On the other hand, a vertex can
have several edges. When an edge connects several vertices, it is called an hyperedge and the resulting
structure is called an hypergraph.
Edge class
The Edge class is a class used for a graph construction in association with the Vertex class. An edge is
used to connect vertices. Normally, an edge connects two vertices. The number of vertices attached to an
edge is called the cardinality of that edge. When the edge cardinality is one, the edge is called a self-
loop. This mean that the edge connects the vertex to itself. This last point is merely a definition but
present the advantage of defining an hyperedge as a set of vertices.
Vertex class
The Vertex is the other class used for the graph construction. and operates with the edge class. A vertex
is used to reference edges. the number of edges referenced by a vertex is called the degree of that
vertex.
Graph
The Graph class is class that represent either a graph or a hypergraph. By definition, a graph is
collection of edges and vertices. There are numerous property attached to graph. Formally, a graph
consists of a set of edges, a set of vertices and the associated endpoints. However, the implementation
is designed in a way so that each edge and vertex carry its associated objects. This method ensures that
the graph is fully defined by only its two sets.
Graph construction
The graph construction is quite simple and proceed by adding edges and vertices. The base system does not
enforce rules on the graph structure. it is possible to add con connected vertices as well as
unreferenced edges.
Edge construction
An edge is constructed by simply invoking the default constructor. Optionally, a client object can be
attached to the edge.
# create a default edge
const edge (afnix:gfx:Edge)
# create an edge with a client object
const hello (afnix:gfx:Edge "hello")
The edge-p predicate can be used to check for the object type. When an edge is created with client
object, the get-client method can be used to access that object.
Vertex construction
A vertex is constructed a way similar to the Edge> object. The vertex is constructed by simply invoking
the default constructor. Optionally, a client object can be attached to the edge.
# create a default vertex
const vrtx (afnix:gfx:Vertex)
# create an vertex with a client object
const world (afnix:gfx:Vertex "world")
The vertex-p predicate can be used to check for the object type. When a vertex is created with a client
object, the get-client method can be used to access that object.
Graph construction
A graph is constructed by simply adding edges and vertices to it. The graph-p predicate can be use to
assert the graph type. the graph class also supports the concept of client object which can be attached
at construction or with the set-client method.
const graph (afnix:gfx:Graph)
The add method can be used to add edges or vertices to the graph. The important point is that during the
construction process, the graph structure is updated with the proper number of edge and vertices.
# create a graph
const g (afnix:gfx:Graph)
assert true (afnix:gfx:graph-p g)
# create an edge and add vertices
const edge (afnix:gfx:Edge)
edge:add (afnix:gfx:Vertex "hello")
edge:add (afnix:gfx:Vertex "world")
assert 2 (edge:degree)
# add the edge to the graph and check
g:add edge
assert 1 (g:number-of-edges)
assert 2 (g:number-of-vertices)
# check for nodes and edges
assert true (afnix:gfx:edge-p (g:get-edge 0))
assert true (afnix:gfx:vertex-p (g:get-vertex 0))
assert true (afnix:gfx:vertex-p (g:get-vertex 1))
STANDARD GRAPH REFERENCE
Edge
The Edge class is a class used for a graph construction in association with the Vertex class. An edge is
used to connect vertices. Normally, an edge connects two vertices. The number of vertices attached to an
edge is called the cardinality of that edge. A client object can also be attached to the class.
Predicate
edge-p
Inheritance
Object
Constructors
Edge (none)
The Edge constructor create an empty edge.
Edge (Object)
The Edge constructor create an edge with a client object.
Methods
reset -> none (none)
The reset method reset all vertices attached to the edge.
cardinality -> Integer (none)
The cardinality method returns the cardinality of the edge. The cardinality of an edge is the
number of attached vertices.
add -> Vertex (Vertex)
The add method attach a vertex to this edge. The method return the argument vertex.
get -> Vertex (Integer)
The get method returns the attached vertex by index. If the index is out-of range, and exception
is raised.
get-client -> Object (none)
The get-client method returns the edge client object. If the client object is not set, nil is
returned.
set-client -> Object (Object)
The set-client method sets the edge client object. The object is returned by this method.
Vertex
The Vertex class is a class used for a graph construction in association with the Edge class. An vertex
is an edge node. The number of edges referenced by a vertex is called the degree of that vertex. A client
object can also be attached to the object.
Predicate
vertex-p
Inheritance
Object
Constructors
Vertex (none)
The Vertex constructor create an empty vertex.
Vertex (Object)
The Vertex constructor create a vertex with a client object.
Methods
reset -> none (none)
The reset method reset all edges attached to the vertex.
degree -> Integer (none)
The degree method returns the degree of the vertex. The degree of a vertex is the number of
referenced edges.
add -> Edge (Edge)
The add method references an edge with this vertex. The method return the argument edge.
get -> Edge (Integer)
The get method returns the referenced edge by index. If the index is out-of range, and exception
is raised.
get-client -> Object (none)
The get-client method returns the vertex client object. If the client object is not set, nil is
returned.
set-client -> Object (Object)
The set-client method sets the vertex client object. The object is returned by this method.
Graph
The Graph object is a general graph class that manages a set of edges and vertices. The graph operates by
adding edges and vertices to it. The graph object also accepts a client object in a way similar to the
Edge and Vertex classes
Predicate
graph-p
Inheritance
Object
Constructors
Graph (none)
The Graph constructor create an empty graph.
Graph (Object)
The Graph constructor create a graph with a client object.
Methods
reset -> none (none)
The reset method reset the graph
reset-edges -> none (none)
The reset-edges method reset all edges attached to the graph.
reset-vertices -> none (none)
The reset-vertices method reset all vertices attached to the graph.
add -> Object (Vertex|Edge)
The add method adds a vertex or an edge to the graph. When adding an edge, the methods check that
the source and target vertices are also part of the graph.
exists -> Boolean (Vertex|Edge)
The exists method returns true if the vertex or edge argument exists in the graph.
get-edge -> Edge (Integer)
The get-edge method returns an edge by index. If the index is out-of-range, an exception is
raised.
get-vertex -> Vertex (Integer)
The get-vertex method returns a vertex by index. If the index is out-of-range, an exception is
raised.
number-of-vertices -> Integer (none)
The number-of-vertices methods returns the number of vertices in the graph.
number-of-edges -> Integer (none)
The number-of-edges methods returns the number of edges in the graph.
get-client -> Object (none)
The get-client method returns the graph client object. If the client object is not set, nil is
returned.
set-client -> Object (Object)
The set-client method sets the graph client object. The object is returned by this method.
AFNIX 2013-09-23 gfx(3)