Class: RGL::Edge::DirectedEdge

Inherits:
Object
  • Object
show all
Defined in:
lib/rgl/base.rb

Overview

Simply a directed pair (source -> target). Most library functions try do omit to instantiate edges. They instead use two vertex parameters for representing edges (see each_edge). If a client wants to store edges explicitly DirecteEdge or UnDirectedEdge instances are returned (i.e. Graph#edges).

Direct Known Subclasses

UnDirectedEdge

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(a, b) ⇒ DirectedEdge

Create a new DirectedEdge with source a and target b.



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# File 'lib/rgl/base.rb', line 35

def initialize (a,b)
  @source, @target = a,b
end

Instance Attribute Details

#source ⇒ Object

Returns the value of attribute source.



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# File 'lib/rgl/base.rb', line 27

def source
  @source
end

#target ⇒ Object

Returns the value of attribute target.



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# File 'lib/rgl/base.rb', line 27

def target
  @target
end

Class Method Details

.[](*a) ⇒ Object

Can be used to create an edge from a two element array.



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# File 'lib/rgl/base.rb', line 30

def self.[](*a)
  new(a[0],a[1])
end

Instance Method Details

#<=>(e) ⇒ Object

Sort support is dispatched to the <=> method of Array



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# File 'lib/rgl/base.rb', line 63

def <=> e
  self.to_a <=> e.to_a
end

#[](index) ⇒ Object

Edges can be indexed. edge == edge.source, edge == edge.target for all n>0. Edges can thus be used as a two element array.



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# File 'lib/rgl/base.rb', line 53

def [](index); index.zero? ? source : target; end

#eql?(edge) ⇒ Boolean Also known as: ==

Two directed edges (u,v) and (x,y) are equal iff u == x and v == y. eql? is needed when edges are inserted into a Set. eql? is aliased to ==.

Returns:

  • (Boolean) 


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# File 'lib/rgl/base.rb', line 41

def eql?(edge)
  source == edge.source and target == edge.target
end

#reverse ⇒ Object

Returns (v,u) if self == (u,v).



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# File 'lib/rgl/base.rb', line 47

def reverse
  self.class.new(target, source)
end

#to_a ⇒ Object

Returns the array [source,target].



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# File 'lib/rgl/base.rb', line 60

def to_a; [source,target]; end

#to_s ⇒ Object

DirectedEdge.to_s == “(1-2)”



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# File 'lib/rgl/base.rb', line 56

def to_s
  "(#{source}-#{target})"
end