Class: Zadt::Graph

Inherits:
Object
  • Object
show all
Defined in:
lib/zadt/AbstractDataTypes/Graph/graph.rb

Direct Known Subclasses

DiGraph, FaceGraph

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Graph

init_v allows for initial vertices (not generally used)



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 15

def initialize
  #@vertices is ALL vertices on the graph
  @vertices = []
  #@edges is ALL edges on the graph
  @edges = []
  @value = Hash.new
end

Instance Attribute Details

#edges ⇒ Object (readonly)

Which are connected by



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 9

def edges
  @edges
end

#value ⇒ Object

Contains



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 12

def value
  @value
end

#vertices ⇒ Object (readonly)

Made up of



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 6

def vertices
  @vertices
end

Class Method Details

.help ⇒ Object 



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 27

def self.help
  Graph.show_help_message
end

Instance Method Details

#add_vertex ⇒ Object

Add a vertex



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 32

def add_vertex
  vertex = Vertex.new
  @vertices << vertex
  vertex
end

#break_connection(v1, v2) ⇒ Object 



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 83

def break_connection(v1, v2)
  raise "First vertex does not exist" if !v1
  raise "Second vertex does not exist" if !v2

  if is_connected?(v1, v2)
    # Find edge
    edge = find_connection(v1, v2)
    # Remove edge from edges catalog
    @edges.delete(edge)
    #Remove edge from vertices
    v1.edges.delete(edge)
    v2.edges.delete(edge)
    v1.connections.delete(v2)
    v2.connections.delete(v1)
  else
    raise "Vertices are not connected"
  end
end

#find_connection(v1, v2) ⇒ Object

Find the edge connecting two vertices



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 69

def find_connection(v1, v2)
  raise "not a vertex" unless v1.is_a?(Vertex) && v2.is_a?(Vertex)
  raise "Vertices not connected" if !is_connected?(v1, v2)
  connection = v1.edges.select {|edge| edge.connection.include?(v2)}
  raise "Error finding connection" if connection.length > 1
  connection.first
end

#help ⇒ Object 



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 23

def help
  Graph.help
end

#is_connected?(v1, v2) ⇒ Boolean

Returns whether two vertices are connected

Returns:

  • (Boolean) 


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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 78

def is_connected?(v1, v2)
  raise "not a vertex" unless v1.is_a?(Vertex) && v2.is_a?(Vertex)
  v1.connections.include?(v2)
end

#make_connection(v1, v2) ⇒ Object

Make an edge between two vertices



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 54

def make_connection(v1, v2)
  raise "not a vertex" unless v1.is_a?(Vertex) && v2.is_a?(Vertex)
  raise "already connected" if is_connected?(v1, v2)
  # Make new edge
  edge = Edge.new(v1, v2)
  # Connect the two using the vertex method "connect"
  v1.connect(v2, edge)
  v2.connect(v1, edge)

  # Add to edge catalog
  @edges << edge
  edge
end

#remove_vertex(vertex) ⇒ Object

Remove a vertex



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# File 'lib/zadt/AbstractDataTypes/Graph/graph.rb', line 39

def remove_vertex(vertex)
  # The vertex must exist
  raise "not a vertex" unless vertex.is_a?(Vertex)
  if !vertex
    raise "Vertex does not exist"
  # The vertex must not be connected to anything
  elsif !vertex.connections.empty?
    raise "Vertex has edges.  Break them first."
  # If it exists and isn't connected, delete it
  else
    @vertices.delete(vertex)
  end
end